FOUS11 KWBC 012025
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
325 PM EST Thu Jan 1 2026

Valid 00Z Fri Jan 02 2026 - 00Z Mon Jan 05 2026

...Great Lakes...
Days 1-3...

Persistent west-northwesterly flow continues across the Great
Lakes over the next few days. This is following in the wake of a
strong arctic front that exited the East Coast to kick off the new
year. This cyclonic flow pattern will be enhanced late tonight
into Friday as another shortwave passes through the flow, leading
to renewed CAA before another weak shortwave swings through on
Saturday and ridging finally develops by the end of the forecast
period.

The primary snowfall hazard will be associated with widespread
heavy lake effect snow (LES) in the favored W/NW snow belts. The
most intense LES will likely begin late tonight through Friday
night as 850mb temperatures plummet to as low as -15C to -20C,
across lakes that, while they have cooled, are mostly ice- free.
This will lead to impressive SBCAPE as high 5000-1000 J/kg to
support a long duration 1-2+"/hr LES event, especially downwind of
Lakes Erie and Ontario due to upstream connections. The heaviest
accumulations D1 and D2 are expected across the Chautauqua Ridge
and along/just barely south of the Tug Hill plateau before
shifting a little south into D1.5-D2. WPC probabilities are high

80%) for 6+ inches in these areas D1, continuing east of Lake

Ontario D2. Locally 2-4 feet of additional snow is possible east
of Lake Ontario before heavy LES wanes during late-D2 into D3.
Downwind of the other Great Lakes, WPC probabilities D1 feature a
low risk (20-40%) for 6+ inches in the eastern U.P., but this
wanes quickly during D2.


...Western U.S. Mountain Ranges...
Days 1-3...

Shortwave with subtropical origins will cross over the central
Great Basin tonight and Central Rockies early Friday over an
expanding Rockies upper-level ridge that will help amplify an
eastern Pacific trough over the next few days. Downstream of this
initial shortwave/impulse, snow levels will remain elevated at
7000-9000 ft throughout much of the Great Basin, Four Corners and central/northern Rockies before settling around 70000ft by the end
of D1. WPC probabilities D1 for 6+ inches of snow reach above 70%
in parts of the Wasatch, Central Rockies, and Tetons/Wyoming Range
of the Northern Rockies.

Then on D2-D3 a more pronounced surge of precipitation spreads
onshore CA once again as a deep trough amplifies offshore,
resulting in impressively amplified southerly flow. This will push
moisture onshore as IVT exceeds 500 kg/m/s (>80% chance). Once
again snow levels will be elevated within the accompanying WAA,
reaching as high as 8000 ft into the Sierra (although much lower
around 6000 ft across the Shasta/Trinity region). The pronounced
moisture will result in heavy snow again above these levels, and
with SLR expected to be low, it will be an impactful snowfall due
to snow load. Precipitation will also reach northward along the
West Coast mountains to the Cascades and inland across the Great
Basin towards the favorable upslope southwest facing terrain. Snow
levels will remain around 6000ft across these regions, with lower
levels (around 4000-5000ft) in the Cascades. WPC probabilities
D2-D3 are high (>70%) for more than 6 inches across the Sierra and
northern CA ranges, as well as the WA Cascades, Sawtooths of ID,
and Tetons of WY. More than two feet of snow is likely (70-90%)
over the next three days in the Sierra.


...Columbia Basin and Gorge...
Day 1...

Increasing southerly mid-level flow over the Pacific Coast will
continue to spread moisture northward tonight, aided by a
weakening shortwave lifting from CA into the northern Great Basin.
As this moisture spreads into the Pacific Northwest, it will
overrun a slowly retreating ridge of high pressure, manifesting
with easterly winds draining into the Columbia Basin/Gorge to
maintain cold surface air. This setup is favorable for light
freezing rain with modest accretions as reflected by WPC
probabilities that reach 20-40% for 0.1 inches of ice after 00Z
this evening. Although amounts are generally light, impacted
travel is likely tonight into Friday morning due to slippery
roadways.


Weiss/Snell



$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 020753
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
253 AM EST Fri Jan 2 2026

Valid 12Z Fri Jan 02 2026 - 12Z Mon Jan 05 2026

...Great Lakes...
Days 1-3...

Ongoing lake effect snow (LES) Will continue in earnest today,
especially across the eastern U.P., and downwind of Lakes Erie and
Ontario. This LES will be driven by persistent CAA across the
lakes, leading to steep lapse rates and inversion depths that climb
towards 800mb, leading to 500-750 J/kg of lake-induced instability.
While the mean low-level flow will be a bit more W than NW, this
will help tap an upstream connection from Superior, across Huron,
and towards Lake Ontario, indicating the heaviest snowfall will
likely be along and south of the Tug Hill Plateau through D1 and
into D2 before winding down in response to brief shortwave ridging.
While periods of heavy snow are also likely in portions of the
northern L.P. and along the Chautauqua ridge, the persistence and
intensity of this snowfall should be less. This is reflected by WPC probabilities for 4+ inches on D1 that area 30-50% in the eastern
U.P. and along the Chautauqua Ridge, but above 90% east of Lake
Ontario, where locally 2+ feet is likely on D1. During D2 the
intensity and coverage of LES wanes, but WPC probabilities for 4+
inches remain above 50% near Oswego, NY.

After a brief respite in response to the aforementioned shortwave
ridging, two separate, but fast moving, shortwaves will crest the
ridge to the west and dive rapidly from Saskatchewan/Alberta across
the Great Lakes. The first of these will race southeast Saturday
aftn/night, and while some enhanced ascent and subtly increased
moisture will result in light synoptic snowfall, additional
accumulations from eastern MN through western NY should be minimal.

A more substantial impulse will then drop southeast in a similar
fashion Sunday night, but this impulse will be accompanied by
greater moisture as it originates from the Pacific and ejects from
the Northern Plains rather than central Canada. This will again be
fast moving, but will have more pronounced synoptic lift in
response to height falls, PVA, LFQ jet diffluence, and more robust
850mb WAA leading to enhanced fgen. At this time, the speed of the
system is expected to limit total snowfall, but briefly heavy snow
rates thanks to idealized ascent into the DGZ could produce a
narrow swath of more than 4 inches as reflected by WPC
probabilities that are as high as 50-70% for 4+ inches from near
Duluth, MN eastward through much of the U.P and the neighboring
portions of WI.


...Western U.S. Mountain Ranges...
Days 1-3...

An active period of weather continues across much of the West as
Pacific moisture repeatedly surges onshore in response to
persistent troughing offshore.

For D1, a brief period of ridging will blossom along the Pacific
Coast, but downstream into the Intermountain West a shortwave with
Pacific origin will lift steadily northeast while de-amplifying.
This will result in a stripe of precipitation arcing from the
Northern to the Central Rockies, and falling as snow above
6000-7000 ft. WPC probabilities D1 reach above 70% for 6+ inches
near the Tetons of WY and the Park Range of CO, with more
widespread elevated probabilities for 4+ inches across much of the
rest of the terrain in this region.

Then beginning late D1 and continuing into D3, much more pronounced
moisture begins to pivot onshore the Pacific Coast. This will be in
response to an impressive trough aligned just offshore, from which
a surface low will track northeast towards WA state by Sunday
morning, with a secondary wave tracking towards northern CA Sunday
aftn. While these surface lows will help enhance local ascent, in
general moisture will be pronounced across much of the West due to
increasing southerly flow downstream of the primary trough axis
pushing IVT well onshore with magnitudes above 500 kg/m/s. As is
typical with strong IVT plumes, they will be driven both by Pacific
jet energy and warm advection, resulting in elevated snow levels
climbing to 7000-9000 ft ahead of the first wave, and while they
will rise again with the secondary wave, they will generally be
much lower, 5000-7000 ft on D3, even lower, around 3500 ft, in the
Cascades and interior Northwest.

Any ascent forced through synoptic features or upslope enhancement
will cause rounds of heavy snowfall above these elevations both
Saturday and Sunday. WPC probabilities steadily increase and expand
through the weekend, with widespread high chances (>70%) for 4+
inches reaching from the Olympics, along the entirety of the
Cascades, the Shasta region, the Sierra, and through much of the Northern/Central Rockies and into the Wasatch, by Monday morning.
While the heaviest snowfall is likely in the Sierra where many
locations above 6000 ft could experience 2-5 feet of snow, much of
the higher terrain of the West could receive 1-2 feet before
coverage wanes just beyond D3. This will likely bring considerable
impacts to the higher elevations due to generally low SLR snow,
with difficult travel likely across the Sierra Passes.


...Central Plains...
Day 1...

A fast moving clipper rounding the western ridge and dropping
southeast over the Central Plains today will be of subtropical
origin. Although this feature will be progressive and of modest
amplitude as it weakens, it will produce sufficient ascent into a
moistening column to produce a narrow corridor of mixed
precipitation in the vicinity of northeast Nebraska. While total
precipitation will be modest, WPC probabilities indicate a 70-90%
chance of at least 0.01" of freezing rain, with locally up to 0.1"
of ice possible leading to hazardous travel.


Weiss



$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 021934
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
234 PM EST Fri Jan 2 2026

Valid 00Z Sat Jan 03 2026 - 00Z Tue Jan 06 2026

...Central Plains...
Day 1...

A fast moving clipper rounding the western ridge and dropping
southeast over the Central Plains today will have sufficient 290K
isentropic ascent and 850mb WAA to foster precipitation over
eastern NE and as far east the lower MO River Valley. Soundings
show a pronounced warm nose between 850-750mb to cause a wintry mix
with surface-850mb temps sub-freezing. WPC probabilities indicate
a 70-90% chance of at least 0.01" of freezing rain, with locally up
to 0.1" of ice possible leading to hazardous travel. The WSSI does
depict Minor Impacts from Ainsworth on south and east to US routes
30 and 81 near Columbus, suggesting hazardous travel is a concern
in these areas through this evening. There is the potential for
some travel impacts all the way to the MO River, including the
Omaha metro area this evening.


...Lake Effect Snow...
Days 1-2...

Ongoing lake effect snow (LES) will continue this afternoon,
especially across the eastern U.P., and downwind of Lakes Erie and
Ontario. This LES will be driven by persistent CAA across the
lakes, leading to steep lapse rates and inversion depths that climb
towards 800mb, leading to 500-750 J/kg of lake-induced
instability. While the mean low-level flow will be a bit more W
than NW, this will help tap an upstream connection from Superior,
across Huron, and towards Lake Ontario, indicating the heaviest
snowfall will likely be along and south of the Tug Hill Plateau
through D1 and into D2 before winding down in response to brief
shortwave ridging. While periods of heavy snow are also likely in
portions of the northern L.P. and along the Chautauqua ridge, the
persistence and intensity of this snowfall should be less. This is
reflected by WPC probabilities showing moderate-to-high chances
(50-70%) for 4+ inches through Saturday over the eastern U.P. and
along the Chautauqua Ridge. The heaviest snowfall will be downwind
of Lake Ontario through Saturday with additional snowfall totals of
12-20" around Oswego, NY.

After a brief respite in response to the aforementioned shortwave
ridging, two separate, but fast moving, shortwaves will crest the
ridge to the west and dive rapidly from Saskatchewan/Alberta across
the Great Lakes. The first of these will race southeast Saturday
aftn/night, and while some enhanced ascent and subtly increased
moisture will result in light synoptic snowfall, additional
accumulations from eastern MN through western NY should be minimal.


...Upper Midwest...
Days 2-3...

One of the 500mb disturbances responsible for heavy mountain snow
in the West will round the ridge axis over the southern Plains and
head for the Upper Midwest on Sunday. The Upper Midwest lies
beneath a coupling 250mb jet streak structure that coincides with
500mb PVA and 700mb Q-vector convergence Sunday afternoon that then
moves over the Great Lakes Sunday night. In addition to the synoptic-
scale ascent aloft, strengthening 850-700mb WAA and FGEN will give
rise to a band of heavy snow from northern MN and northern WI
Sunday afternoon to the Upper Great Lakes Sunday night. There is
likely to be a >0C warm nose in southern ND, central MN, and
southern WI that leads to an icy wintry mix. As the 500mb vort max
moves east Sunday night, it will run into a stronger confluent zone
over Ontario that shears out the disturbance and leads to
lessening snowfall rates. By Monday morning, periods of snow will
envelope Upstate NY and reach as far inland as the northern
Appalachians, but snow will generally be on the lighter side with
the upper-level forcing weakening.

WPC probabilities show low-to-moderate chances (30-50)% for 24-hour
snowfall totals >4" over the heart of MI's Upper Peninsula.
Localized totals >6" are likely, especially given the favorable
meteorological drivers that are at play. Many deterministic
members do show a swath of >6" of snow, but given the wide cast of
potential QPF totals and the different placement of the band, it is
leading to greater dispersion in ensemble mean guidance. At this
time, residents from northern MN and northern WI to the MI U.P. and
tip of MI's Mitten should prepare for at least Minor Impacts.
WPC's WSSI-P does show low-to-moderate chances (30-50%) for Minor
Impacts in the Lower MI U.P. and northeast WI. The WSSI-P also
shows low chances (10-30%) for Minor Impacts (hazardous travel
conditions) over western WI and central MN due to ice
accumulations.


...Western U.S. Mountain Ranges...
Days 1-3...

An active weather pattern continues across much of the West as
repeated rounds of Pacific moisture surge onshore and advance
eastward across the Rockies.

An anchored troughing pattern along the west coast of North
America is forecast to continue for several more days. This
anomalous longwave trough, paired with a strong ridge over Mexico,
is supporting steadfast SWrly flow out of the Pacific that is
supplying copious amounts of moisture over the western-third of the
CONUS. As snow over the central Rockies dissipates this afternoon,
an upper-level ridge axis over the Great Basin will slide east
thanks to the approach of a large upper-low west of CA. An
expansive IVT, with moisture originating out of the subtropics,
will surpass 500 kg/m/s and extend almost the full length of the
U.S. West Coast tonight. This moisture plume will be heaviest along
the track of a frontal system (low 980s low west of OR) that slams
into the West Coast tonight and early Saturday morning. While this
system has a good deal of moisture at its disposal, their is a
significant lack of a continental polar (cP) air-mass ahead of the
storm. Still, the combination of upslope enhancement and persistent
500mb PVA when paired with the onslaught of Pacific moisture will
foster mountain snow throughout much of the West this week.

Snow levels throughout CA will initially be in the 7000-9000ft
range ahead of this first system (higher snow levels farther
south), but as subsequent upper- level disturbances approach as
they round the base of the longwave trough positioned off the West
Coast, 500-700mb height falls and CAA should result in snow levels
coming down to the 5000-7000ft late Saturday and to close out the
weekend. Snow levels will be a little lower in the Pacific
Northwest and northern Rockies, but most snowfall will still reside
in the more remote reaches of these mountains ranges with some
welcomed snow to ski resorts in these regions. That said, the
bigger impacts will be in the Sierra Nevada where low SLR's and
steadily lowering snow levels should prompt heavy snow for many of
the mountain range's passes.

Snowfall totals above 6,000ft in the Sierra Nevada, over the next
three days, are likely to range between 2-5 feet with localized
amounts in the higher peaks of the southern Sierra Nevada topping 6
feet. The WSSI is lit up with Major to even Extreme Impacts due to
Snow Amount, with the I-80 portion beginning near Truckee on west
to around mile marker 158, likely to see significant travel
impacts beginning Saturday night and continuing into Sunday.
Farther north, WPC probabilities show high chances (>70%) for
snowfall totals >4" in the Cascades, Olympics, and on south to the Siskiyou/Shasta mountains of northern CA. Farther east, snowfall on
the order of 8-12" are likely in the Lewis Range, Blue, and
Sawtooth Mountains above 6000ft, the Tetons, Absaroka, and Bear
River above 7000ft, and the Wind River and Uinta/Wasatch above
8,000ft. The Sawtooth, Tetons, Wind River, and Bear River Ranges
all sport high chances (>70%) for snowfall totals >12" with some
localized totals topping 24" expected.


Mullinax/Weiss



$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 030716
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
216 AM EST Sat Jan 3 2026

Valid 12Z Sat Jan 03 2026 - 12Z Tue Jan 06 2026


...Upper Midwest/Great Lakes...
Days 1-3...

Impressive lake effect snow (LES) will continue today, especially
across the U.P. of MI and downwind of Lakes Erie and Ontario. This
LES has already been impressive, with 24-36 hour snowfall of 1-3
feet or more in some areas east of Lake Ontario, and today's LES
will likely be heavy once again. Continued CAA, reinforced at least
slightly by a weak shortwave moving overhead, will maintain steep
lapse rates and lake-induced instability to support snowfall rates
of 1-2"/hr as reflected by HREF 1"/hr snowfall probabilities
above 40%. A more NNW wind shift behind this shortwave will cause
bands to drop a little south of the recent heavy snowfall, and
WPC probabilities for an additional 4+ inches peak above 70%
southeast of Lake Ontario, with lower potential (10-50% chance)
across the eastern U.P. of MI and near the southtowns of Buffalo,
NY to the Chautauqua Ridge.

Thereafter, brief shortwave ridging envelops the region before a
more significant shortwave crests the western ridge and races
eastward towards the Great Lakes. This impulse will be of Pacific
origin, and accompanying elevated moisture (PWs above 0.5" and the
90th climatological percentile) will track in tandem with this
feature. Forcing for ascent driven by height falls/PVA,
intensifying left-exit jet level diffluence, and strengthening WAA
will provide the impetus for heavy snowfall, with 1"/hr snowfall
rates likely within any banded structures. The system will remain
progressive, and the guidance has trended a little SW over the past
few runs, but accompanying NBM probabilities have been relatively
steady. This indicates increasing confidence for a narrow swath of
heavy snowfall, for which WPC probabilities indicate a moderate
risk (50-70%) for 4+ inches across the U.P. of MI D2 into D3, with
several inches likely as well from near Duluth, MN through the
northern L.P. of MI.

Additionally, on the southern edge of this precipitation swath,
some mixed freezing rain/sleet is likely as the warm nose edges
northward in response to the pronounced WAA. This could result in a
corridor of impactful icing from far eastern ND through
central/southern MN and into southern WI. Although WPC
probabilities for 0.1" of ice are less than 10%, some icy roadways
and hazardous travel are possible Sunday evening.


...Western U.S. Mountain Ranges...
Days 1-3...

A persistent mid-level trough positioned west of the Pacific Coast
will periodically shed impulses northeast and onshore, with each
subsequent impulse spreading energy across most of the
Intermountain West.

This persistent trough will manifest with 850-500mb heights that
will remain at or below the 10th climatological percentile into
Monday before finally relaxing. As spokes of vorticity swing out
from this trough and push onshore (the first likely this aftn with
a secondary impulse lifting northeast on Sunday night), the
subtropical origin will expand anomalous moisture onshore thanks to
surges of elevated IVT. As is typical with this setup, the
corresponding WAA will help drive snow levels upward, but a series
of cold front accompanying the aforementioned impulses will temper
the overall warming, leading to a general slow drop in snow levels
through the period. By Tuesday, as the core of the trough finally
pivots towards CA, snow levels could be quite low in the Cascades
and Pacific Northwest, only 1500-2500 ft, and just 3000-5000 ft
elsewhere after being as high as 6000-8000 ft to start the forecast
period. This suggests that each wave of precipitation through the
forecast period will result in more expansive and impactful snow at
lower elevations.

During D1, the heaviest snowfall is expected in the Sierra and
northern CA terrain where WPC probabilities for 12+ inches reach
70-90+ percent, and 1-3 feet is likely above 6000 ft. WPC
probabilities for 6+ inches D1 of more than 50% cover a large
portion of the Intermountain West terrain as well, with locally 1
foot possible in parts of the Wind Rivers, Sawtooth/Salmon River
ranges, and Cascades. During D2, waves of precipitation continue,
and support another day of heavy snow, focused across the Sierra
and Shasta/Trinity area, with lighter accumulations elsewhere, but
still covering much of the terrain from the Wasatch/Uintas and
points north and west. Multiple feet of snow is again expected in
the Sierra (WPC probabilities for 12+ inches above 90%) with more
than 1 foot possible in the higher terrain of the northern
UT/western WY, and into ID. Finally on D3, precipitation intensity
wanes, but additional significant snowfall accumulations are likely
in much of the area as this prolonged event begins to wane.

With extremely heavy snow likely in the Sierra and northern CA
mountains, totaling 4-6+ feet in some areas, and snow levels
falling below pass levels, travel will become extremely challenging
into early next week, and extreme impacts are possible due to the
combination of heavy snow and low SLR.


Weiss

$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 032058
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
358 PM EST Sat Jan 3 2026

Valid 00Z Sun Jan 04 2026 - 00Z Wed Jan 07 2026


...Northern Plains/Upper Midwest/Great Lakes/Interior Northeast...
Days 1-3...

Single band lake effect snow from Lake Ontario is forecast to sag
south as it eases in intensity into the evening the latest clipper
(this one perhaps the weakest this week) works its way east from
Michigan.

The next clipper of Pacific origin and crosses the northern Plains
early Sunday with widespread wintry precip breaking out around
midday near the MN/Dakotas border. Elevated moisture (PWs above
0.5" and the 90th climatological percentile), ascent driven by
height falls/PVA, intensifying left-exit jet level diffluence, and strengthening WAA will accompany this feature. Rates quickly become
heavy over northern MN Sunday afternoon with a wintry mix on the
southern edge of the precip, but mostly snow, heavy at times with

1"/hr rates (per the 12Z HREF) within banded structures. The

system will remain progressive, with a preference for QPF from the
wetter global models vs the CAMs which have a narrower precip
shield as often has on synoptically forced winter storms. The risk
for 6" through Sunday night has risen over northern MI with Day 1.5
PWPF now around 35% around both sides of the Straits of Mackinac.
Day 1.5 probs for >4" are over 30% from the Bayfield Peninsula of
WI across the U.P. and Upper L.P. along with far northern WI and
northern Door Co.

The strong warm nose could result in a corridor of impactful icing
over central MN (including the Twin Cities metro) and
western/central WI. WPC ice probabilities for >0.1" remain less
than 10%, but some icy roadways and hazardous travel are possible
Sunday afternoon and evening.

This wave tracks into New York Monday before weakening as it
continues to push into a ridge. Day 2 PWPF for >4" is limited to
around 30% for the Tug Hill Plateau where some lake enhancement can
be expected on westerly low level flow.

The next wave is southern stream, coming from CA and crossing
Nebraska/Iowa Monday night. The northern precip shield should bring
mainly light to moderate wintry mix over central MN and northern
WI into Tuesday. While 12Z guidance generally agrees on a narrow
swath of mainly freezing rain, there is still meridional
differences of central vs northern WI. Even the 12Z EC-AIFS shifted
north with its QPF axis (northern WI) from the 06Z run (which
favored north-central WI). So stay tuned on Tuesday icing threats
for the Upper Midwest.



...Western U.S. Mountain Ranges...
Days 1-3...

A persistent longwave trough positioned off the Pacific Coast will
continued to shed impulses onshore at least through Monday night,
with each subsequent impulse spreading energy across most of the
Intermountain West.

The southern stream trough off CA with the northern stream end
shifting over the Northwest will maintain 850-500mb heights at or
below the 10th climatological percentile into Monday before finally
relaxing as the southern stream low likely closes off west of CA.
Pacific moisture flows inland on WAA ahead of the main trough axis,
but lowering height falls will allow lower snow levels to continue
shifting across the West.

Sierra Nevada...Days 1/2...

The current trough pushing into OR/northern CA this afternoon
shifts south across CA through Sunday with the heaviest precip on
the Sierra Nevada. Snow levels drop to around 6000ft tonight on
along the length of the Sierra Nevada and even drop to around
6500ft in the SoCal ranges Sunday.

The next wave is the northern stream that shifts into the OR/WA
coast Sunday and works its way down through central CA into Monday
night before focusing offshore. Snow levels on the Sierra Nevada
are lower with the next wave, generally around 5000ft, but drop to
around 4500ft Monday evening though snow rates will be less than
from the current wave.

Day 1 PWPF for >24" is 50-80% above 7000ft across the length of the
Sierra Nevada. Then for Day 2 the PWPF for additional >12" over
the length of the Sierra Nevada is 50-80% above about 6500ft.

With prolonged heavy snow for the Sierra and northern CA
mountains, totaling 4-6+ feet in some areas, and snow levels
below pass levels, travel will remain extremely challenging through
Monday. Localized extreme impacts are possible due to the
combination of heavy snow and low SLR.

Cascades...Days 1-3...
Repeating waves into the Pacific Northwest through Sunday evening
maintain moderate to heavy snow rates on the WA/OR Cascades with
snow levels remaining around 4000/5000ft tonight. As the northern
stream shortwave trough pushes through later Sunday, the snow
levels drop to 3000/4000ft before rates ease Sunday night. Day 1
PWPF for >8" is 50-80% in the higher Cascades with 40-70% for >6"
on Day 2.
There's a lull for the Cascades then through Monday night before
the next northern stream trough approaches Washington with snow
levels starting on the WA Cascades around 1200ft Tuesday morning,
rising to around 2500ft by Tuesday evening. Day 3 probs for >6" are
50-90% throughout the WA Cascades and Olympics above about 2500ft.


Northern to Central Rockies...
Days 1-3...

The current lull over the northern Rockies ends by this evening as
moisture streaming from CA flows across ID and western MT/WY
through tonight before drifting south to UT/southern WY Sunday
night. Snow levels begin around 6000ft at onset and drop to around
5000ft Sunday (3000-4000ft for northern ID/MT). Day 1 snow probs
for >8" are 50-80% in the central ID and western WY ranges as well
as around Glacier NP and west through northern ID. The focus shifts
south a bit for Day 2 where probs for >8" are 50-80% for the
Wasatch Front and Uinta as well as the Wind River again in WY while
central ID values are around 50%.

Day 3 probabilities are lower across the Rockies as rates decrease
under weakening flow. Probs for >6" are 50-80% in the Tetons and
40-60% in the Park Range of CO, the Wind Rivers, central ID up
through the Bitterroots.


Jackson


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 040819
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
319 AM EST Sun Jan 4 2026

Valid 12Z Sun Jan 04 2026 - 12Z Wed Jan 07 2026


...Northern Plains/Upper Midwest/Great Lakes/Interior Northeast...
Days 1-3...

Some modest lake effect snow (LES) will continue through Sunday
aftn, but primarily within a single band south/southeast of Lake
Ontario with upstream connection to Lakes Huron and Superior.
Additional snowfall across this region should be light as reflected
by WPC probabilities for an additional 2+" of just 10-30%,
although brief 1"/hr rates are possible (10-30% chance).

Thereafter, the mid-level pattern flattens a bit as shortwave
ridging expands from the west, leading to pinched and more
progressive flow across the region. Within this flow, two back-to-
back shortwaves will traverse the region bringing rounds of wintry
weather.

The first of these will emerge from the High Plains Sunday morning
and push due east across the Great Lakes in a de-amplifying manner
as it becomes absorbed into the pinched westerlies. Despite the
weakening amplitude, height falls, PVA, and the left-exit region of
a strengthening jet streak will produce deep layer ascent, and
the intensification of this jet streak will likely result in
enhanced omega despite the weakening amplitude of the shortwave. At
the same time, increasing and impressive 925-850mb WAA will spread
northeast ahead of this impulse, aligning with the best left-exit
dynamics and the associated response to produce impressive fgen but
with limited temporal duration. Since this feature will be of
Pacific origin, the accompanying moisture will be impressive as
reflected by NAEFS PWs that are above the 97th percentile, aligned
with the strongest ascent. This suggests that as precipitation
expands from MN through the U.P., and into the northern L.P., a
narrow band of heavy snow will develop which has a 60-80% chance
of producing 1"/hr snowfall rates. The duration of these will,
again, be limited to the progressive nature of the wave, but WPC
probabilities for 4+ inches are above 50% from the Arrowhead of MN
eastward through the northern L.P. of MI, with locally 6-8"
possible (30% chance) in portions of the eastern U.P.

Additionally, south of this axis of heavy snow, a corridor of
modest mixed precipitation, including freezing rain, is likely as
the WAA surges a warm nose to around +3C at 850-800mb. The
refreezing layer is quite deep, so this may manifest more as sleet
than freezing rain, but hazardous travel is Sunday evening from MN
through central WI where WPC probabilities for 0.01" of ice are
50-70%.

This lead wave will continue to track into New England before
exiting to the Atlantic Monday night, but additional snowfall is
expected to be light, generally 1-3", although locally higher in
the Tug Hill Plateau through lake enhancement, as ascent weakens.

The next shortwave follows quickly in the wake of the first, and
emerges from CA Sunday evening before racing to reach the Corn Belt
by Tuesday morning. This impulse will track along the southern
subtropical jet, which is progged to intensify over the Central
Plains, reaching towards 140 kts. The favorable overlap of the LFQ
and height falls downstream of the shortwave will likely lead to
surface low pressure development Monday night near Iowa, with this
low then tracking steadily northeast into Ontario by Tuesday
evening. While there is still some spatial spread in the placement
of this low according to the different ensemble clusters, the
increasing ascent will lead to another round of wintry
precipitation from Minnesota through the Great Lakes (where a mix
of freezing rain and snow is likely), with additional mixed
precipitation spreading into New England by the end of the forecast
period. Total ascent with this secondary wave should be less
intense than the lead wave, and the thermal evolution is quite
complex due to potential secondary low development in the Gulf of
Maine, but at this time WPC probabilities for 2+ inches of snow are
just 10-30% in the higher elevations of Upstate NY and northern New
England.

For the freezing rain, WPC probabilities indicate a high risk

70% chance) of at least 0.01" of ice from central MN near the

Twin Cities through much of WI and MI, and into central and
northern New England. The greatest risk for at least 0.1" of ice is
likely in parts of northern WI, northern MI, and the higher
elevations of the Catskills, Adirondacks, and southern Greens.


...Western U.S. Mountain Ranges...
Days 1-2...

The active west continues into early next week as an anomalous
trough persists just off the Pacific coast through Tuesday morning
before amplifying into a closed low which then undercuts towards
Baja by the end of the forecast period.

Downstream of this trough, nearly continuous S/SW flow will shed
spokes of vorticity onshore, with the accompanying height falls/PVA
leading to rounds of precipitation across much of the western
CONUS. At the same time, a subtropical jet will amplify and waver
from CA through the Central Plains, providing additionally enhanced
ascent. The combination of persistent SW mid-level flow with the
wavering jet stream will surge periods of elevated IVT onshore,
resulting in PW plumes that occasionally exceed the 90th
climatological percentile. While there may be periods of enhanced
ascent locally across different regions, in general the next 48
hours appear to be synoptically forced with broad large-scale
ascent, locally enhanced through PVA where the vorticity lobes
stream overhead, and through upslope enhancement. The strongest
upslope flow continues to be appear focused over the Sierra where
snowfall will be prolific, but heavy snow is likely through Monday
night across much of the region.

With broad SW flow encompassing the region, the accompanying WAA
will surge snow levels to as high as 6000-8000 ft in the Great
Basin and Rockies D1 (but generally 3000-5000 ft elsewhere), before
steadily falling through D2 as a cold front pushes eastward and the
trough axis finally swings farther east to the coast. By 12Z
Tuesday, snow levels are expected to be generally 1500-2500 ft in
the north, to 5000-6000 ft in the south. 2-day WPC probabilities
(12Z Sunday through 12Z Tuesday) feature a high risk (>70% chance)
for 12+ inches in the Sierra, northern CA ranges, Uintas, Tetons,
Wind Rivers, and portions of the Salmon River/Sawtooth/Bitterroots,
with lesser snowfall expected at the other regional terrain. In
the Sierra, 2-4 feet is possible in the higher elevations.


...Cascades...
Day 3..

Mid-level flow across the Northern Pacific will become pinched and
zonal Tuesday, while a weak impulses approaches the coast and may
move onshore overnight into Wednesday morning. This zonal mid-level
flow will be topped by a strengthening Pacific jet streak which
will drop gradually southward such that the overlap of PVA/height
falls will match the greatest LFQ diffluence to provide ample
ascent. This will be aided by upslope enhancement into the terrain
thanks to the westerly flow, producing brief but impressive deep
layer lift into IVT that has a >80% chance of exceeding 250 kg/m/s.
While westerly IVT does not usually result in as impressive of
precipitation as that with a S or SW component, a fully saturated
column with steepening lapse rates will result leading to a period
of heavy snow in the Olympics and Cascades of OR and WA. Snow
levels will be generally 2000-3000 ft during this time, so pass
level impacts leading to hazardous travel are expected. WPC
probabilities for more than 8 inches of snow reach 70+%, with more
than 1 foot possible at the passes (Snoqualmie and Stevens
included).



Weiss


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 041921
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
221 PM EST Sun Jan 4 2026

Valid 00Z Mon Jan 05 2026 - 00Z Thu Jan 08 2026


...Upper Midwest/Great Lakes/Interior Northeast...
Days 1-3...

Over the next few days, two back-to-back progressive shortwave
troughs will bring a combination of snow and ice to the Upper
Midwest, Great Lakes, and interior Northeast.

The first disturbance is making its way over the Upper Midwest and
this afternoon and will be positioned over the Great Lakes tonight.
500mb height falls, sufficient PVA, and the left-exit region of a
strengthening jet streak will produce deep layer ascent. At the
same time, increasing and impressive 925-700mb WAA will spread
northeast ahead of the shortwave trough, creating a narrow FGEN
band over northern WI and the MI U.P. this evening. Moisture
associated with this feature comes from the highly active Pacific
jet stream pattern, reflected by NAEFS PWs that are above the 97th
percentile. With these synoptic and mesoscale ingredients at play,
a narrow band of heavy snow will develop which, according to latest
12Z HREF guidance, show high chances (>70%) of producing at least
1"/hr snowfall rates from far northern WI to the southern periphery
of MI's U.P. and the Tip of MI's Mitten this evening. Duration
will be limited given the upper-level disturbance's progressive
nature, but WPC probabilities for 4+ inches are above 50% from the
central MI U.P. to the tip of MI's Mitten, with locally 6-8"
possible (30-50% chance) in portions of the eastern U.P..

Farther south, an icy wintry mix is likely as WAA produces a warm
nose to around +3C at 850-750mb. The refreezing layer is quite deep
below 850mb, so some sleet may help to cut into the freezing rain accumulations. Nevertheless, hazardous travel is expected this
evening from northern MN through central WI and central MI where
WPC probabilities for 0.01" of ice are 50-70%.

This first shortwave trough will race into the Northeast before
exiting to the Atlantic Monday night, but snowfall is expected to
be light. Snowfall totals over northern NY and as far east as the
Green Mountains are likely to receive 1-3" of snowfall, although
locally higher in the Tug Hill Plateau due to lake enhancement is
possible.

As snow concludes across the Northeast Monday afternoon, the next
Pacific shortwave reaches the Corn Belt Monday night. This
disturbance will have sufficient synoptic-scale forcing thanks to
a strengthening subtropical jet streak that strengthens to the tune
of 140 kts. Left-exit region dynamics and height falls downstream
of the shortwave will spawn low pressure over eastern NE Monday
evening, with the low then tracking east across the Midwest
Tuesday morning and over southern Ontario by Tuesday evening. There
remains some uncertainty on the placement of the heaviest QPF, but
increasing ascent will foster another round of wintry
precipitation from Minnesota through the Great Lakes Monday night
into Tuesday. As the low reaches southern Ontario Tuesday evening,
additional mixed precipitation spreads across New England Tuesday
night and into Wednesday. Northern New England has the better odds
for light-to- moderate snowfall on Wednesday as a coastal low may
support a deformation zone of snowfall that produces 1-4" of
snowfall.

While the first system had a fair amount of snowfall over the Upper
Great Lakes, the second system from the Midwest and Great Lakes to
the interior Northeast will largely be an ice producer. WPC
probabilities indicate a high risk (>70% chance) of at least 0.01"
of ice from central MN near the Twin Cities through the heart of
the Great Lakes and into the higher terrain of the interior
Northeast. The greatest risk for at least 0.1" of ice is likely in
parts of central MN, northern WI, and the higher elevations of the
Catskills, Adirondacks, and southern Greens.


...Western U.S. Mountain Ranges...
Days 1-2...

The active west continues into the first half of the week as an
anomalous trough persists just off the Pacific coast through
Tuesday morning before amplifying into a closed low that heads
towards Baja by Wednesday. This should conclude the snow in the
Sierra Nevada by Tuesday, but lingering snow in the Northern
Rockies will continue into Wednesday.

Downstream of this trough, nearly continuous S/SW flow will shed
spokes of vorticity onshore, with the accompanying height falls/PVA
leading to rounds of precipitation across much of the western
CONUS. At the same time, a subtropical jet will amplify and waver
from CA through the Central Plains, providing additional
synoptically-induced ascent. The combination of persistent SW mid-
level flow will foster elevated IVT today and into Monday,
resulting in PW plumes that occasionally exceed the 90th
climatological percentile. While periods of enhanced ascent
will differ across different regions, the next 36-48 hours appear
to be synoptically forced with broad large-scale ascent and
through upslope enhancement. The strongest upslope flow continues
to be appear focused over the Sierra Nevada through tonight where
snowfall will be prolific at times, but heavy snow is likely to
wind down late Monday as the upper low pinches off from the polar
jet and dives south of CA Monday night.

With broad SW flow engulfing the region, ongoing WAA will surge
snow levels to as high as 6000-8000 ft in the Great Basin and
Rockies D1 (but generally 3000-5000 ft elsewhere), before steadily
falling through D2 as a cold front pushes eastward and the trough
axis finally swings farther east to the coast. By 12Z Tuesday, snow
levels are expected to be generally 1500-2500 ft in the north, to
5000-6000 ft in the south. 2-day WPC probabilities (00Z Monday
through 00Z Wednesday) feature a high risk (>70% chance) for 12+
inches in the Sierra, northern CA ranges, Uintas, Tetons, Wind
Rivers, and portions of the Salmon River/Sawtooth/Bitterroots, with
lesser snowfall expected at the other regional terrain. In the
Sierra, an additional 1-2 feet is expected in the higher
elevations.


...Cascades & Olympics...
Days 2-3...

A powerful storm system traversing southern AK and an unusually
strong subtropical ridge north of Hawaii will create a strong
thermal gradient that that directs a strong >140kt 250mb jet
streak at the Pacific NW. The Olympics and Cascades will reside
beneath the left-exit region of this jet streak at the same time as
500mb height falls unfold on Tuesday. Between falling heights and
upslope enhancement driven by a westerly IVT topping 300 kg/m/s,
snow levels will fall to as low as 2,000ft Tuesday night in the WA
Cascades and Olympics and 3,000ft in the OR Cascades. By Wednesday,
a secondary disturbance ejecting out of the Gulf of AK trough will
bring another round of mountain snow to the Cascades on Wednesday.
WPC probabilities show high chances (>70%) for snowfall >12" above
3,000ft in the Cascades and Olympics with 2-4 feet of snow likely
in the northern WA Cascades above 4,000ft. Expect impacts at pass-
level in WA as the WSSI currently shows Moderate Impacts (hazardous
driving conditions and potential closures) for Snoqualmie and
Stevens Passes where as much as 1-2 feet of snowfall is forecast.
Note that the WSSI-P shows low-to-moderate chances (20-40%) for
locally Major Impacts, which imply increased odds for closures and
delays at these passes.


Weiss/Mullinax





$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 050758
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
258 AM EST Mon Jan 5 2026

Valid 12Z Mon Jan 05 2026 - 12Z Thu Jan 08 2026


...Upper Midwest/Great Lakes/Northeast...
Days 1-3...

Shortwave currently over Wisconsin will track rapidly eastward
while continuing to de-amplify this morning, likely moving off the
Maine coast by Tuesday morning. The weakening trend of this impulse
driven by the absorption into more pinched westerlies will
gradually weaken ascent such that ongoing heavy snow near the Great
Lakes will transition to primarily light snow from Upstate NY
through central/northern New England. Light accumulations of 1-3"
are expected in this region, with locally as much as 4" possible in
the Tug Hill Plateau due to lake enhancement and southern Greens
thanks to upslope flow. In general, however, the most substantial
impacts from this shortwave will end before the new D1 period
begins.

Almost as quickly as this first shortwave exits New England, a
second impulse following quickly in its wake will begin to
organize over the Upper Midwest Tuesday morning. This next impulse
stems from a weak vorticity lobe which ejected from the Pacific
trough late Sunday, crested the western ridge, and begins to deepen
as it moves towards the Great Lakes Tuesday. Unlike the lead
shortwave which weakens with time, this feature is expected to
gradually strengthen and gain amplitude as it moves eastward into
Wednesday. Additionally, this shortwave will be joined by an
impressive jet streak to its south (reaching 160 kts from the
Central Plains to the Ohio Valley) and accompanied by Pacific
moisture (PWs above the 90th climatological percentile according to
NAEFS). The resulting surface low which will develop will
additionally enhance ascent, and a swath of moderate to heavy
precipitation is likely from the western Great Lakes through New
England.

Thermally, the environment is marginal for wintry precipitation due
to antecedent ridging aloft and strengthening WAA, so p-type from
WI, across the Great Lakes, and into at least central New England
will likely be a mix of rain, snow, sleet, and freezing rain. The
mixed precip will result in some impacts, but WSSI-P indicates only
minor impacts expected due to the progressive nature and mixed
p-type in this region. Still, WPC probabilities for ice accreting
to at least 0.1" reach 30-50% from near the Twin Cities through
central WI and into lower MI. Locally 0.2" of ice is possible, but
snow amounts are expected to be very light as the guidance has
trended a bit warmer tonight.

During D3, secondary low pressure development in the Gulf of Maine
could make snowfall and impacts a bit more impressive over New
England. While there remains considerable uncertainty into the
timing of this secondary low development, a surge of cold air
wrapping behind (and a developing in-situ CAD) should keep p-type
primarily snow in northern New England and mixed
snow/sleet/freezing rain in the higher elevations of Upstate NY and central/southern New England. This is reflected by an increase in
WPC snowfall probabilities, which, while still modest, are as high
as 10-30% D2 into D3 in the higher terrain of NH and ME. Icing to
the south of the snow may locally reach above 0.1" (30-50% chance
in the Adirondacks, Greens, and Monadnocks).


...California...
Day 1...

Amplifying trough off the Pacific Coast will deepen into a closed
low today, with this closed center drifting southeast towards Baja
California by Wednesday morning. Downstream of this evolution,
continued SW mid-level flow and aligned Pacific jet energy will
pump moisture northeast, reflected by high probabilities (>80%
chance) for IVT exceeding 250 kg/m/s surging into CA. Although this
IVT will be pushed onshore via WAA, snow levels will generally
remain around 5000 ft as the WAA is offset by slowly sinking
heights downstream of the trough axis. At the surface, of wave of
low pressure will drop along the CA coast, and while there is
considerable spread in the longitudinal placement of this feature,
sufficient additional ascent into the moistening column will
result in periods of heavy snow above 5000 ft in the Sierra and
northern CA ranges D1, and WPC probabilities are high (>90%) for at
least 6 inches more of snow, with more than 12 inches possible in
the higher terrain, especially around Mt. Shasta.


...Olympics, Cascades, and Northern/Central Rockies...
Days 2-3...

Mid-level flow becomes increasingly zonal across the Pacific,
directing energy and moisture into the Pacific Northwest beginning
on Tuesday. Aloft, a jet streak will intensify directly atop the
zonal mid-level flow, providing additional funneling of moisture
onshore before the jet starts to slowly sink southward on
Wednesday. This is reflected by a brief period of elevated IVT

90% chance exceeding 250 kg/m/s but less than 25% chance of 500

kg/m/s) Tuesday into OR/WA. As forcing for ascent increases D2 and
D3 through gradual height falls, left-exit diffluence, and
impressive upslope into the Olympics, Cascades, and Northern
Rockies, heavy snowfall will result in these areas, with snow
levels Tuesday 2000-3000 ft, falling to as low as 1000 ft late
Wednesday (higher but still just around 2500 ft in the Central
Rockies).

This cooling column, increasing ascent, and impressive moisture
indicates that heavy snowfall will become increasingly widespread
above these snow levels, especially in the upwind regions of the
Olympics, Cascades, and Northern Rockies. Forecast soundings
suggest steepening lapse rates up to as high as 750mb, which
indicates accumulating snow could occur even lower than these snow
levels, and the NBM 10th% fall to as low as 500 ft in the Pacific
Northwest, so lowland snow is possible late in the forecast period.
However, the most significant accumulations, which are likely to
be impressive, will be above 2000 ft, but will encompass most of
the Cascade and Northern Rockies Passes leading to challenging
travel later this week. WPC probabilities D2 for more than 6 inches
of snow are high (>70%) in the Olympics, Cascades of WA and OR,
the Northern Rockies, and as far south as the NW WY ranges (Tetons,
Wind Rivers), with 1-2 feet likely in the higher elevations of
these ranges. During D3, precip wanes a bit across the
Intermountain West, but persists in heavy fashion across the
Olympics and Cascades where WPC probabilities for 12+ inches remain
above 50%. As noted above, the falling snow levels will result in
dangerous travel across all of the important Cascades Passes this
week.



Weiss


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 051907
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
207 PM EST Mon Jan 5 2026

Valid 00Z Tue Jan 06 2026 - 00Z Fri Jan 09 2026


...Upper Midwest/Great Lakes/Northeast...
Days 1-3...

A progressive shortwave trough over southern Ontario is producing
weak PVA over the Northeast, along with minor 850-700mb WAA ahead
of the trough. Sufficient 850-300mb moisture is present to support
periods of light-to-moderate snow over the Northeast this afternoon
and evening, but snow should taper off not long after midnight.
Minor snowfall accumulations of 1-4" are expected with some slick
conditions on untreated surfaces possible.

As the trough in the Northeast exits east into the North Atlantic
tonight, another disturbance with Pacific origins follows on its
heels as it develops a wave of low pressure in the Midwest. Located
beneath the divergent left-exit region of a 150kt 250mb jet streak,
the storm will gradually strengthen at the same time as 850-700mb
WAA ahead of the low also increases. While this disturbance is
similar to the one over the Northeast in that it is progressive,
there will be a stronger warm nose aloft that makes ice the primary
concern over the Midwest and Great Lakes this time around. An icy
wintry mix is beginning over parts of the eastern Dakotas and
central MN this afternoon, but as WAA increases, so will the rates
of sleet and freezing rain. Look for icy conditions to unfold
across WI and over MI's U.P. (Upper Peninsula) tonight, then over
MI's L.P. (Lower Peninsula) by Tuesday morning. The wintry mix may
linger over the Great Lakes and Midwest through midday Tuesday, but
should taper off by Tuesday evening, meaning there could still be
lingering icy conditions for the Tuesday afternoon rush hour. WPC
probabilities show at least moderate chances (>50%) for ice
accumulations over one-tenth of an inch of ice from southern MN to
northern MI. The WSSI shows a large swath of at least Minor
Impacts (slick travel conditions possible, use caution) from
southern MN on east through northern WI and into central MI. There
is an area denoting Moderate Impacts (hazardous travel conditions,
closures possible) in the heart of WI where localized ice
accumulations could approach one-quarter inch.

As the storm tracks over southern MI Tuesday afternoon, the same synoptically-forced mechanisms aloft will support periods of snow
over the Adirondacks and northern New England. Farther south, a
wintry mix of sleet and freezing rain will envelope central NY,
northern NJ, and northeast PA starting as early as Tuesday
afternoon, then advance east into the heart of New England with the
Green Berkshires, and Worcester Hills Tuesday night. Throwing a
wrench into the forecast is the expected development of a coastal
low along a coastal front off southern New England. This transition
from the primary low over southern Ontario to the new coastal low
off the MA Capes will be pivotal in how long central New England
stays a wintry mix and when/if they transition to snow. Northern
Maine and the White Mountains have the greater chances of seeing
snow as their primary precip type for this event Tuesday night and
into Wednesday morning. Through the daytime hours Wednesday, an icy
wintry mix is likely to linger over coastal ME but all
precipitation tapers off by Wednesday evening.

WPC probabilities show high chances (>70%) for ice accumulations

0.01" over the Catskills, Adirondacks, and much of interior New

England. The Adirondacks, Berkshires, Green, and Worcester Hills
have moderate chances (40-60%) for ice accumulations over one-tenth
of an inch. In terms of snowfall, the tallest peaks of the
Adirondacks, northern Greens, Whites, and northern ME show moderate
chances (40-60%) for snowfall over 2" through Wednesday evening,
but should the coastal low strengthen faster, localized snowfall
totals of 4-6" could transpire in northern ME. WSSI shows these
winter hazards generally look to cause Minor Impacts, indicating
the potential for some areas of hazardous travel due to snow and
ice Tuesday night and through Wednesday.


...Olympics, Cascades, and Northern/Central Rockies...
Days 2-3...

A powerful storm system over southern AK will work in tandem with
an unusually strong subtropical ridge north of HI to create a
robust 160kt 250mb jet streak in the northeast Pacific. This
enhanced polar jet will direct a potent IVT that ranges between
250-500 kg/m/s at the Pacific NW, while at the same time, being
co-located beneath the divergent left-exit region of the
aforementioned 250mb jet streak. While moisture content is not
overly anomalous, the westerly IVT supporting enhanced upslope
flow, falling mid-upper level heights, and supportive jet streak
dynamics will support rounds of heavy mountain snow over the
Cascades and Olympics. Snow levels will fall to as low as 2,000ft,
although the heavier and more impactful snow will be observed above
3,000ft. The heaviest snowfall arrives Tuesday afternoon, and
following a brief break in the heavier snowfall rates early
Wednesday morning, another disturbance arrives later in the day
with more snow in the Cascades and Olympics. This time, with a
colder air-mass aloft, snow levels dip to as low as 1,000ft
Wednesday afternoon and continuing into Thursday.

With snow continuously falling in these ranges through Thursday,
WPC's 72-hour snowfall probabilities are quite impressive with high
chances (>70%) for snowfall totals >24" above 3,000ft in the
Cascades and Olympics, including passes such as Snoqualmie and
Stevens. Current WSSI shows Moderate Impacts at these passes
(hazardous travel, potential closures) but given the higher end
snowfall potential, the WSSI-P does depict a scenario (20-30%
potential) for Major Impacts that would imply more dangerous travel
conditions. Regardless, multiple days of heavy snowfall is
expected, so passes will likely contend with prolonged delays and
potential closures.

The Pacific moisture spills east into the Northern Rockies as well
through the first half of the week. There is already lingering
Pacific moisture leftover from the heavy rainfall and mountain snow
in CA that is supporting periods of snow today and into tonight in
the Sawtooth, Bitterroots, Tetons, Wind River, and as far south as
the more remote reaches of the CO Rockies. As Pacific moisture
arrives Tuesday afternoon thanks to 250 kg/m/s IVT extending as far
east as eastern WA, periods of heavy snow ensue above 4,000ft in
the northern Bitterroots, above 5,000ft in the Lewis Range, Blue,
and Sawtooth Mountains, and above 7,000ft in the Absaroka, Tetons,
and Bear River Ranges. WPC probabilities over the next 72-hours
show high chances (>70%) for over 12" of snow in these ranges with
moderate chances (>50%) for snowfall eclipsing 24" in the more
remote elevations of the Bitterroots, Sawtooth, Tetons, and Wind
River ranges. The peaks of the Tetons sport the best odds of seeing
localized snowfall totals over 3 feet.

By Wednesday evening, attention turns to the central Rockies where
they will be placed ahead of two approaching shortwave troughs; one
diving south and east from the Pacific NW and another approaching
from northwest Mexico. As the former disturbance deepens Wednesday
night and into Thursday, periods of mountain snow are likely to
envelope the Wasatch, Uinta, all of the CO Rockies, and even as far
south as the Mogollon Rim and the Rockies of NM. Guidance shows a
fair amount of uncertainty in the handling of these two features,
so confidence in totals remains low. That said, the pattern support accumulating mountains snow (generally above 7,000ft) Wednesday
night and into Tuesday. Residents along the Front Range of the
CO/WY/NM Rockies will want to monitor the forecast closely as this
could result cause impacts to travel and commerce late week.


Mullinax





$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 060751
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
251 AM EST Tue Jan 6 2026

Valid 12Z Tue Jan 06 2026 - 12Z Fri Jan 09 2026


...Great Lakes & Northeast...
Days 1-2...

Amplifying shortwave will move steadily eastward from the Great
Lakes tonight, passing off the New England coast Wednesday morning.
While the flow in which this impulse will be embedded is generally
zonal, some modest amplification is progged by the consensus, with
the subsequent height falls overlapping modest LFQ diffluence from
a jet streak to the south to enhance deep layer lift, especially in
the Northeast. This will likely result in two waves of surface low
pressure: one moving from MI into Ontario, with secondary
development occurring off the coast of Maine. The speed at which
this second low develops, as well as its latitude, will have a
strong influence on how much cold air can lock in across New
England within the in-situ wedge. While the trends in the guidance
continue to be a slightly farther south and stronger offshore low,
which will enable more cold air to lock in, mixed precip is still
likely to be the dominant p-type outside of the higher terrain and
across northern New England. This system should remain progressive
as well, limiting total impacts and amounts.

For areas that receive mostly snow (the Adirondacks and northern
New England) WPC probabilities for 4+ inches of accumulations are
modest at 10-30%, but locally reach as high as 50% in NH and ME. South
of there, a mix including freezing rain is likely, which could
produce more than 0.1" of ice (30-50% chance) highest in the
Greens, Berkshires, and Worcester Hills.


...Olympics, Cascades, and Northern/Central Rockies...
Days 1-3...

A powerful storm system over southern AK will work in tandem with
an unusually strong subtropical ridge north of HI to create a
robust 160kt 250mb jet streak in the northeast Pacific. This
will transport potent IVT eastward within pinched but generally
zonal flow, reflected by GEFS probabilities that exceed 80% for 250
kg/m/s, but are less than 25% for 500 kg/m/s. This increasing
moisture, while not exceptional, will be wrung out efficiently by
PVA within shortwaves traversing the flow, the LFQ of a slowly
sinking but strengthening Pacific jet streak, and persistent, at
times continuous, upslope flow, especially in the Olympics and
Cascades. Snow levels will fall to as low as 2,000ft, although the
heavier and more impactful snow will be observed above 3,000ft.
The heaviest snowfall arrives D1, and following a brief break in
the heavier snowfall rates early Wednesday morning, another
disturbance arrives later in the day with more snow in the Cascades
and Olympics. This time, with a colder air-mass aloft, snow levels
dip to as low as 1,000ft Wednesday afternoon and continuing into
Thursday. Although snow levels remain generally at or above 1,000
ft, steepening lapse rates aloft with continued ascent could result
in locally lower snowfall, reflected by the NBM 10th percentile
snow level falling to around 600 ft. While this should still
prevent significant accumulations in the lowlands, some of the
foothills west of the Cascades could see light snowfall on D2 as
well.

With snow nearly continuously falling in these ranges through
Thursday, WPC's 72-hour snowfall probabilities are quite impressive
with high chances (>70%) for snowfall totals >24" above 3,000ft in
the Cascades and Olympics, including passes such as Snoqualmie and
Stevens. At the higher elevations, 4-6 feet of snow is possible.
This snowfall, despite elevated SLRs as the column cools, will
result in dangerous travel across most Cascade Passes, with the
WSSI-P indicating a moderate threat (50-70%) of major impacts
through the Cascades. Motorists should prepare for dangerous travel
and potential pass closures this week.

Farther east into the Northern Rockies and then pivoting down to
the Central Rockies, spokes of energy within the generally zonal
flow will provide sufficient ascent to wring out moisture that
spills across the Cascades. Although snowfall farther east should
be somewhat less impressive than points west, WPC probabilities for
12+ inches during the next 3 days are high (>90%) in the higher
terrain from the Blue Mountains of OR through most of the Northern
Rockies, and down through the Tetons, Wind Rivers, and parts of the
Wasatch. Locally, 2-4 feet is possible in the highest peaks of
these ranges, and pass-level travel will also be significantly
impacted this week.


...Four Corners States...
Day 3...

Shortwave digging southeast from the Pacific Northwest will amplify
rapidly as it approaches the Central Rockies, potentially closing
off over the CO/NM High Plains Thursday night. There continues to
be a lot of spread in the mid-level evolution leading to lower than
typical confidence by D3, however, the cluster analysis (from 00Z/5
which is the most recent available) suggests there is potential for
continued deepening due to more pronounced upstream ridging leading
to a deeper trough (supported by more than 60% of the members,
although many of these are from the CMCE which may be somewhat
under-dispersive at this time). However, the trends in the
incoming 00z suite suggest the trough continues to be deeper, which
may result in a more substantial winter weather event.

As the guidance has trended steadily slower and faster with this
feature, suggesting more impressive deep layer ascent, the
resulting downstream jet streak has also intensified and arced
more impressively poleward. As this jet arcs northward, the
overlap of LFQ diffluence with height falls will likely lead to lee
side cyclogenesis Thursday evening, within a column that, while
will feature generally normal to below normal PWs, will saturate in
response to increasing low- level easterly flow around the
strengthening surface low. With steep lapse rates aloft helping to
cool the column, and flow becoming increasingly favorable to
upslope into the terrain, at least light snow is becoming likely
for much of the terrain and into the High Plains of CO/NM,
including the I-25 metro which has experienced a relative dearth of
snowfall so far this season. While adjustments in the forecast are
likely, current WPC snow probabilities indicate a high risk (>70%
chance) for 4+ inches of snow across much of the CO Rockies,
including the Front Range, and portions of the Wasatch, and down to
the White Mountains of AZ. The lower elevations of I-25 and into
the High Plains have a 10-30% chance of 4+ inches, although locally
higher amounts are possible across the Palmer Divide and Raton
Mesa.


Weiss


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 062040
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
340 PM EST Tue Jan 6 2026

Valid 00Z Wed Jan 07 2026 - 00Z Sat Jan 10 2026


...Northeast...
Day 1...

An amplifying shortwave along with a trailing shortwave over the
Upper Midwest this evening will move steadily eastward into/through
the Northeast overnight and early tomorrow morning. As a modest
jet streak moves off the Mid-Atlantic coast this evening, broad
lift on the poleward side of the jet will help promote an expanding
area of precipitation across the region atop a marginal to cold
environment. At the surface, the dueling mid-level shortwaves will
help take a lead surface low over western NY (BUF to ART)
overnight and a newly developing surface low near southeast Mass by
12Z Wed that will lift toward Nova Scotia through the afternoon.
Given the marginal temperatures at precip onset over at least some
of the interior and WAA aloft, a mix of freezing rain and some
sleet to the south and mostly snow to the north (along the Canadian
border) is likely as the decaying lead low allows a northerly
fetch to continue to bring in some colder air to northern
locations. The system will exit the region by tomorrow evening
given the progressive flow.

For areas that receive mostly snow (the higher elevations of the
Adirondacks and northern New England), WPC probabilities for at
least 4 inches of snow are modest at 10-40% with most areas likely
seeing 2-3 inches of snow. Along and south of I-90, a mix of mostly
freezing rain but some sleet is likely. WPC probabilities of at
least 0.10" icing are highest (>50%) in MA along/north of I-90 and
along Route 2, as well as into the southern Green Mountains in VT
and into southern NH. Localized amounts near 0.25" are possible.


...Olympics, Cascades, Great Basin, and Northern/Central Rockies...
Days 1-3...

The strong jet across the North Pacific will dip into the Pac NW
and weaken, but still bring a modest influx of moisture to the
region via several embedded shortwaves. Lead system enters tonight
via a 120kt jet streak with snow to the Cascades and northern
Rockies that will sink southward as the jet digs and dips through
the Great Basin. Snow levels initially around 3000-4000ft will
lower overnight to below 2000ft (WA and eastward) and 3000ft (OR to
ID) by tomorrow morning, with another surge in moisture thereafter
as the second shortwave moves in from the Pacific. Snow levels
will continue to lower to as low as 750-1000ft by early Thursday as precipitation lightens and is increasingly favored in the terrain.
However, this will bring impactful snow to the passes and at least
some light snow to some higher lowland areas around 1000ft.
Precipitation should end in the PacNW by Friday afternoon. WPC
probabilities are >50% for at least 8 inches of snow above
1000-2000ft through the WA/OR Cascades and for at least 18 inches
of snow above 2000-3000ft. Total snow for the highest peaks may
eclipse 3-4ft.

From the northern Rockies southward to the Wasatch and WY ranges,
moisture associated with the Pacific intrusion will still be modest
but sufficient enough to capitalize on upslope enhancement into
the terrain, especially over Idaho and northwestern MT D1 then
through western WY and eventually the Wasatch as the moisture and
trough sink southward and eastward. WPC probabilities for at least
12 inches of snow are >50% above 4000-5000ft (north), 7000ft (WY),
and 7000-8000ft (Wasatch).


...Four Corners States...
Days 2-3...

A vigorous shortwave digging southeast from the Pacific Northwest
will amplify rapidly as it approaches the Four Corners states
(potentially closing off over the high plains of southeast CO and
northeast NM or vicinity) Thursday into Friday, before ejecting
eastward into the central Plains Friday night into Saturday. As
this occurs, a strengthening 120kt+ 250mb jet overspreading the
southern and central Plains will begin to arc poleward, placing the
left exit region in the vicinity of the central and southern
Rockies. The overlap of left exit region diffluence with mid-level
height falls will likely lead to lee side cyclogenesis Thursday
evening, within a column that, while will feature generally normal
to below normal PWs, will saturate in response to increasing low-
level easterly flow around the strengthening surface low. With
steep lapse rates aloft helping to cool the column, and flow
becoming increasingly favorable to upslope into the terrain,
confidence is increasing for a more significant snow event for much
of the central and southern Rockies into the High Plains of CO/NM,
including the I-25 corridor (particularly from Denver to Colorado
Springs) which has experienced a relative dearth of snowfall so far
this season.

While adjustments in the forecast are likely (and the latest
trends suggest those adjustments are likely to be upward), current
WPC snow probabilities now indicate a high risk (>70% chance) for
storm total accumulations of 8+ inches of snow across much of the
CO Rockies (including the Front Range), portions of the Wasatch,
and southward into the higher elevations of northeast AZ and
northwest NM. The lower elevations of I-25 and into the High Plains
now have a 30-60% chance of 4+ inches, although locally higher
amounts, potentially in excess of 8 inches, are also possible
across western portions of the Palmer Divide and Raton Mesa.


Fracasso/Miller/Weiss


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 070816
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
316 AM EST Wed Jan 7 2026

Valid 12Z Wed Jan 07 2026 - 12Z Sat Jan 10 2026


...Northeast...
Day 1...

Amplified but progressive shortwave will track over New England 12Z
Wed - 00Z Thu, exiting quickly to the southeast of Cape Cod
tonight. The two distinct vorticity lobes embedded within this
shortwave will drive the two surface lows (one moving across far
southern Canada while a secondary low develops off the New England
coast), with a wedge in-between the two features supporting cold
air and overrunning precipitation. The primary mechanism for
precipitation development will be the PVA/height falls and
increasing isentropic ascent, especially as the secondary low
development occurs, before the flow shifts to produce NW winds and
CAA. There is still some uncertainty into exactly how strong and at
what speed this transition to CAA will occur, but the models
continue to support slightly more cold air, keeping snow the
primary p-type for northern New York and northern New England, with
a mix including freezing rain as far south as CT/RI, but even here precipitation may end as light snow as the column cools.

Overall ascent is transient and moisture is just slightly
elevated, so total accumulations are expected to be modest. This is
reflected by WPC probabilities for an additional 2+ inches after
12Z Wednesday that are 30-50% in the highest terrain of
northern/central ME, and reach above 50% for 0.01" of ice, focused
across the Worcester Hills and Monadnock Region of NH.


...Pacific Northwest, Great Basin, Northern/Central Rockies...
Days 1-3...

Deep trough over the Pacific will shift its axis inland by Friday,
with longwave ridging expanding across the Pacific Coast on
Saturday. As this ridge blossoms, precipitation will finally wane
across the area, but until then an extended period of active
weather with significant snowfall will continue.

The strong jet currently in place will dig slowly southward in
tandem with an embedded mid-level impulse tracking towards the
Great Basin. This impulse will be generally within zonal flow,
although as the trough kinks to become more amplified, mid-level
divergence will also increase. Despite a weakening of the onshore
mid-level flow, the upper jet will maintain its intensity of around
100 kts, at least early D1, before weakening, providing sufficient
IVT to fuel heavy precipitation from the Pacific Northwest into the
northern Great Basin and northern Rockies. Ascent will be aided
both by upslope flow and a fast moving surface cold front. Although
forcing looks generally transient, WPC probabilities D1 into D2 are
high (>70%) for more than 4 inches of snow from the Cascades
through the Northern Rockies and into the Tetons, Wind Rivers, and
Uintas, as well as the Ruby Mountains of NV. During D2, forcing
along the front pushes into UT/AZ where additional snowfall
exceeding 4" is likely (>70%) in the Wasatch and Mogollon Rim.

Behind this cold front, snow levels will crash, potentially falling
to below 1000 ft across the Pacific Northwest, while a second surge
of moisture occurs. This second moisture plume is driven by the
upstream jet streak from the primary trough axis, with the
impressive LFQ diffluence overlapping a secondary vorticity lobe
for ascent. As this rides into the Cascades, additional forcing for
lift created by upslope flow will wring out moisture as additional
heavy snowfall in the Olympics and Cascades, with moisture spilling
into the Northern Rockies as well. Notably, with this second
impulse, lapse rates are exceptionally steep beneath the core of
the mid-level trough, so any heavier rates will likely pull snow
down to around 600ft (NBM 10th% snow level), suggesting even some
light accumulations are possible in the foothills surrounding
Seattle and Portland (although the true lowlands will likely miss
out on any snow this time around). Still, the greatest impacts will
again be across the Cascades and the Passes where WPC probabilities
D2 into D3 are high (>70%) for an additional 4+ inches, with 2-day
total snowfall of 2-3 feet likely in the higher terrain, with even
1-2 feet possible at the passes.


...Four Corners into the High Plains...
Days 2-3...

Elongated vorticity lobe will spin southeast from the Pacific
Northwest and amplify into deep longwave trough as it approaches
the Four Corners Thursday night. The intensity of this trough
remains uncertain as it amplifies towards the region around 12Z
Friday, but in general the trends have been for a deeper amplitude
while remaining positively tilted. At the same time, the resultant
jet streak downstream of this trough axis will deepen and pivot
northeast, reaching as high as 140 kts across the Southern Plains,
leaving favorable LFQ diffluence into the High Plains and Four
Corners. Where this jet streak overlaps with the most robust height
falls, lee cyclogenesis will likely result, likely in the northeast
plains of New Mexico as reflected by most ensemble members.

This low will move slowly Friday morning before elongating into
faster flow to the northeast by the end of the forecast period.
Before this occurs, a cold front will dig southward through the
High Plains, with the resulting wind field becoming more E/NE and
upsloping into the terrain of CO and NM. This will provide
additional ascent to the region, which will already be influenced
by favorable synoptic lift, suggesting a period of moderate to
heavy precipitation Thursday night through Friday aftn. Most of
this will fall as snow, especially as the cold front sags south and
cools the column through favorable CAA. However, there is still
uncertainty into how much snow will fall, especially from the
Palmer Divide northward where a significant 850mb moisture gradient
is expected. The ECMWF and its ensemble members are much drier
farther north than the other camps, but locations across southern
CO and northern NM have higher confidence in impactful snowfall,
including along the I-25 urban corridor. While the Palmer Divide
will likely experience significant snowfall due to the higher
elevations and more pronounced upslope, areas north of there,
including Denver, may experience lesser snow. However, in an area
that has seen very little snow so far this winter, this could
still be an impactful event for much of the region, with heavy snow
pulling northeast into OK/KS by the end of the period beneath the
upper jet streak.

Although confidence is modest for this time range, current WPC
probabilities are high D2 for at least 6 inches of snow across the
CO Rockies and into the White Mountains of AZ. Late D2 into D3 as
the surface low consolidates and upslope flow improves, WPC
probabilities indicate a greater risk, (50-70% chance), for at
least 6 inches of snow in the Front Range, Palmer Divide, Raton
Mesa, Sangre de Cristos, and into the high plains of southeast CO.


Weiss


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 071950
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
250 PM EST Wed Jan 7 2026

Valid 00Z Thu Jan 08 2026 - 00Z Sun Jan 11 2026


...Pacific Northwest, Great Basin, Northern/Central Rockies...
Days 1-2...

An offshore, well-defined, mid-level shortwave, in tandem with a
~100 kt upper level jet, will dig inland into the Pacific Northwest
this evening. As the northern stream portion of this amplifying
trough advances steadily eastward across the Intermountain West
into the Rockies, a southern stream wave is forecast to dig south
through the Great Basin into the Southwest tomorrow.

Heavy snow currently developing along the Cascades will continue
to spread south through this evening and persist along the range
into tomorrow. Pockets of moderate to heavy snow are also expected
to develop further east from the Blue Mountains into the northern
Rockies tonight. Rates should generally start to wane across the
entire region by late tomorrow as a building upstream ridge begins
to move inland. Areas of light to moderate snow will likely
continue into early Friday before drying out completely across most
areas by late in the day.

The heaviest amounts are expected to fall along the northern
Cascades, where snow levels are forecast to start the period below
2000 ft before dropping below 1000 ft tomorrow. WPC probabilities
indicate that accumulations greater than 8 inches are likely for
many parts of the Washington and northern Oregon Cascades above
2000 ft, including the major passes in northern Washington.

Further south, the digging southern wave will bring crashing snow
levels along with brief but potentially intense snow showers across
the Great Basin tonight. WPC PWPF indicates some of the northern
and central Nevada mountains may see amounts over 8 inches.


...Four Corners into the High Plains...
Days 1-2...

A lead negatively-tilted shortwave will lift out of the southern
Four Corners tonight into Thursday, briefly interacting somewhat
with the wave digging southward from the Pacific Northwest. This
interaction will allow snow to first blossom across the high
valleys and mountains of the central and southern Rockies. As the
lead wave exits, the elongated vorticity lobe spinning southeast
from the Pacific Northwest will amplify into a deep longwave trough
as it approaches the Four Corners Thursday night. The resultant
jet streak downstream of this trough axis will deepen and pivot
northeast, reaching as high as 140 kts across the Southern Plains,
leaving favorable LFQ diffluence into the High Plains and Four
Corners. Where this jet streak overlaps with the most robust height
falls, lee cyclogenesis will likely result, likely in the
northeast plains of New Mexico as reflected by the latest guidance.

This low will move slowly Friday morning before elongating into
faster flow to the northeast by the end of the forecast period.
Before this occurs, a cold front will dig southward through the
High Plains, with the resulting wind field becoming more E/NE and
upsloping into the terrain of CO and NM. This will provide
additional ascent to the region, which will already be influenced
by favorable synoptic lift, suggesting a period of moderate to
heavy precipitation Thursday night through Friday afternoon. Most
of this will fall as snow, especially as the cold front sags south
and cools the column through favorable CAA. However, there is still
uncertainty into how much snow will fall, especially north of the
Palmer Divide, where a significant low-level moisture gradient is
expected to set up. The ECMWF and its ensemble members have been
much drier and farther north than the other camps in previous
cycles, but the latest guidance trends seem to be coming around on
that idea. Farther south, locations across southern CO and northern
NM have higher confidence in impactful snowfall, including the
higher elevations of the Palmer Divide and along the I-25 urban
corridor. In a normal winter, this event would be fairly run-of-
the-mill, but given how warm and dry it's been so far, this could
still end up being an impactful event for much of the region.

Moderate snow then quickly pulls northeast into KS/OK/TX by Friday
morning beneath the upper jet streak before ending by Friday
evening.

The latest WPC probabilities are high on Day 1 for at least 6
inches of snow across the UT/CO Rockies and into the high
elevations of the southern Rockies, including the White Mountains
of AZ. Late Day 1 into Day 2 as the surface low consolidates and
upslope flow ramps up, WPC probabilities show a moderate to high
risk (50-80% chance), for at least 6 inches of snow in the Front
Range, Palmer Divide, Raton Mesa, and Sangre de Cristos. Low to
moderate probabilities for >4 inches then extend into the High
Plains of southeast CO, southwest KS, far western OK, and far
northwest portions of the TX Panhandle.


...Upper Midwest into the Great Lakes...
Day 3...

The deep positively tilted wave responsible for the snow across
the Four Corners (particularly southeast CO and northeast NM) will
eject northeastward into the central Plains late Friday into
Saturday. Meanwhile, another potent wave dropping southward out of
Canada is expected to rapidly close off over the northern Plains
and Upper Midwest. These two features are progged to phase together
later Saturday into Saturday night, forming a large, closed, mid-
level low over the region. This mid-level evolution, combined with
impressive jet dynamics from a powerful 250mb 150kt+ jet streak,
will support the rapid development and deepening of a surface
cyclone across the eastern Great Lakes. As the low develops, a
stream of rich Gulf moisture (with anomalies in excess of 250% of
normal) will be drawn northward and wrapped into the low pressure
system, likely forming a TROWAL and deformation axis across the
Upper Midwest and Great Lakes. The resulting isentropic ascent and strengthening frontogenesis underneath this axis could support a
band (or bands) of heavy snowfall, with the potential for
significant accumulations. This is especially the case late Day 3
on Saturday and especially heading into the Day 4 period on Sunday.

The latest WPC probabilities show low to medium chances (20-50%)
for 24-hr snowfall >4" across eastern Wisconsin into northern
Michigan on Day 3, increasing to medium to high (50-80%) just
beyond the forecast period on Day 4. In fact, Day 4 probabilities
increase to over 50% for snowfall >6" across northern Michigan,
highlighting the potential for a more significant event. Given
these already notable probabilities, trends and future model
cycles will need to be monitored closely as we get closer.


Pereira/Miller/Weiss


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 080813
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
313 AM EST Thu Jan 8 2026

Valid 12Z Thu Jan 08 2026 - 12Z Sun Jan 11 2026


...Pacific Northwest, Great Basin, Northern Rockies...
Days 1-1.5...

A shortwave trough over northern CA this morning will strengthen as
it tracks south and east into the southwestern U.S.. Farther north,
a second shortwave trough over British Columbia will also dig
farther south across the northern Rockies and northeast High
Plains. Residual 700-300mb Pacific moisture will stream across the
Pacific NW and into the both the Northern Rockies and Great Basin
to continue to produce additional mountain snow through Thursday.
Snow levels in the northern Cascades and Olympics will be as low as
1,000ft today, but the heavier snowfall will remain confined to
elevations above 2,000ft. Farther east, the northern Rockies'
heaviest snowfall will be above 5,000ft and above 6,000ft in the
Great Basin. WPC probabilities show high chances (>70%) for
snowfall totals >6" for elevations above 3,000ft in the Cascades
and Olympics. Similar high chance probabilities are present in
parts of the Lewis, Bitterroots, Blue, and Teton Ranges for
additional snowfall >4". Snow will linger longest over the Cascades
and northern Bitterroots through Thursday night, but as the long
awaited upper level ridge builds in on Friday, snow levels will
rise and snow will taper off across all mountains ranges into the
start of the weekend.


...Four Corners into the High Plains...
Days 1-2...

A pair of shortwave troughs will be responsible for rounds of
moderate-to-heavy snowfall over the Central and Southern Rockies,
with some snowfall into the central High Plains also expected. This
morning, a strengthening storm system over western KS and eastern
CO brought along a plume of subtropical moisture that is streaming
over the Four Corner states. Snow levels will dip to as low as
5,000ft in central CO and central UT with light snow falling in the
SLC and Denver metro areas. As this disturbance races into the
Midwest this afternoon, a second and more vigorous upper level
shortwave over the Great Basin heads east for the Four Corners
region, bringing with it not only additional Pacific moisture but
height falls, better PVA, and jet streak dynamics aloft. Guidance
shows a healthy area of 700mb Q-vector convergence shifting from
the Mogollon Rim and Wasatch this morning to the central and
southern Rockies by this afternoon, where periods of snow will
envelope most mountain ranges. Snow levels along the Mogollon Rim
will be as low as 6,000ft, while central and southern UT sees snow
levels still hovering as low as 5,000ft. The Gila Mountains and
southwest CO will also see an uptick in snowfall this afternoon
before tapering off early Friday morning.

Farther east, as the enhanced Q-vector convergence heads for the
Front Range of the Rockies and the High Plains this evening, a
closed 700mb low will develop over northern NM that gives rise to a
surface low forming in lee of the Sangre De Cristo mountains. Low-
level easterly winds over the central High Plains fosters upslope
flow into southern CO and northern NM beginning Thursday night and
peaking Friday morning as the 700mb low tracks just south of Raton
Pass. There remains some disagreement on the placement of the best
700mb FGEN as the 700mb low emerges into northeast NM and tracks
towards the OK/TX Panhandles. Where the best FGEN forcing sets up
and the strength of the 700mb low will be vital in where the
heaviest snowfall occurs and how far east away from the Raton Mesa
and Front Range the band of heavy snow can advance. Beneath the
700mb FGEN, >1"/hr snowfall rates are expected. As the 700mb low
moves northeast Friday afternoon, it will weaken and open up into a
progressive 500mb shortwave, resulting in frontolysis over western
KS that reduces precipitation rates and weakens dynamic cooling
aloft.

At this time, WPC probabilities are highlighting the usual
suspects (Palmer Divide, Front Range, Raton Mesa) as having
moderate-to-high chances (>70%) for snowfall totals >4". I-25 at
Raton Pass sports moderate-to-high chances (50-70%) for snowfall
totals >6". Localized snowfall totals >8" along the peaks of the
Sangre De Cristo and Raton Mesa are possible. Farther east, WPC
probabilities show moderate chances (40-60%) for snowfall totals

4" in southeast CO , southwest KS, the far western OK Panhandle,

and the northwest tip of the TX Panhandle. The WSSI shows
widespread Minor Impacts (winter driving conditions; use caution
when driving) for much of the central High Plains with localized
Moderate Impacts possible.


...Upper Midwest & Great Lakes...
Days 1-3...

An active stretch of potent storm systems will bring a wide range
of winter precip types to the Midwest and Great Lakes the
remainder of the week. The first storm system will track from KS on
north and east into IA this evening, then over northern MI by
Friday morning. Dynamic cooling beneath a coupling jet-streaks
structure is a plausible scenario from as far south and west as
eastern NE to as far north as the MI U.P.. Given the rapid
progression of the QPF shield, accumulating snow over 1" will be
tough for areas south and west of northern WI. However, over
northern WI and the MI U.P., the timing of the changeover to snow
coincides with the middle of the night, allowing for a better
chance for snowfall accumulations. Marquette's area in particular
will have better chances for accumulating snow as onshore, lake-
enhanced snowfall ensues. Snow tapers off Friday morning as the
storm races north into Ontario. WPC probabilities shows moderate
chances (>50%) for snowfall totals >4" in MI's Huron Mountains with
similar >50% probabilities for >2" extending southward into
northern WI. There is also the potential for light ice
accumulations from northern IA and southern MN to northern WI and
the western MI U.P. with WPC probabilities showing moderate chances
(40-60%) for ice accumulations over one-hundreth of an inch. Ice
accumulation could occur near the evening rush hour in southern MN
and central WI.

By Saturday night, the shortwave trough responsible for the heavy
snow in the the southern and central Rockies/High Plains heads east
towards the MS Valley at the same time as a closed 500mb low over
in Canada plunges south into the Upper Midwest. Guidance has come
into better consensus on the northern stream feature effectively
shearing the southern disturbance and becoming the more dominant
feature. As the 500mb low will direct PVA at the Great Lakes, a
strengthening wave of low pressure and 850-700mb WAA will produce a
larger shield of snow developing initially over southern WI and
northern IL. As moisture wraps northward around the deepening
850mb low over northern MI, a TROWAL will pivot over northern WI
and the MI U.P., prompting the development of heavy snow in these
areas Saturday afternoon and persisting into Saturday night. The
low will occlude over Lake Huron early Sunday morning as the
deformation zone of heavy snow pivots over the tip of MI's Mitten.
Once occluded, the upper low will weaken and move east as more
progressive flow over the Canadian Prairies kicks the storm east
into Ontario Sunday afternoon.

WPC probabilities show moderate-to-high chances (50-0%) for
snowfall totals >4" from the Green Bay area in eastern WI on north
and east through the eastern MI U.P. and the northern tier of MI's
L.P. (Lower Peninsula). The tip of MI's L.P. are favored to contend
with the heaviest snowfall given their longer duration beneath the
TROWAL and some lingering lake-enhanced snowfall in wake of the
storm early Sunday. WPC probabilities depict low-to-moderate
chances (30-50%) for snowfall totals >8" here with localized totals
approaching a foot a possibility.


...Interior Northeast...
Day 3...

The storm responsible for heavy snow over the northern Great Lakes
on Saturday will also generate a hazardous wintry mix from
northern PA on northward into the northern Appalachians. The
Northeast will lay ahead of a strong >750kg/m/s IVT that will
direct copious amounts of moisture northward on Saturday. At the
same time, a cold front will provide just enough cold/dry air at
the surface with Canadian high pressure to the north creating a
weak CAD signature over the Northeast. This healthy 850-700mb WAA
will support a classic overrunning setup of >0C air aloft causing a
mixture of sleet/freezing rain to unfold beginning Saturday
afternoon and continuing into Saturday night. Precipitation may
start out as snow in far northern New England, where wet-bulb
temperatures down the surface may initially support snow. Still,
the concern is for mountains such as the Catskills, Berkshires,
Greens, Adirondacks, and Whites where surface temperatures have
better odds of staying sub-freezing Saturday night and into Sunday
morning.

While minor ice accumulations over one-hundreth of an inch are
likely (>70% probabilities) in the Adirondack and Green Mountains,
these ranges also could witness ice accumulations over one-tenth of
an inch, resulting in greater odds for hazardous travels
conditions Saturday evening that linger into Sunday morning. In
terms of snow, the latest forecast generally calls for minor
accumulations (2-4" of snow) over northern Maine, but localized
totals over 6" are possible. WPC's WSSI-P shows >50% chances for
Minor Impacts over the Adirondacks, the Green and White Mountains,
and through much of northern Maine late Saturday into early Sunday.


Mullinax





$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 082020
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
320 PM EST Thu Jan 8 2026

Valid 00Z Fri Jan 09 2026 - 00Z Mon Jan 12 2026


...Upper Midwest & Upper Great Lakes...
Day 1...

A storm system will track from KS this afternoon on north and east
into IA by this evening, then over northern MI by Friday morning
producing a narrow, but potentially heavy stripe of snowfall just
to it's northwest. Dynamic cooling beneath a coupling jet-streaks
structure is a plausible scenario from as far south and west as
eastern NE to as far north as the MI U.P.. Given the rapid
progression of the QPF shield, accumulating snow over 1-2" will be
tough for areas south and west of northern WI. However, over
northern WI and the MI U.P., the timing of the changeover to snow
and the 700 mb low track coincides with the middle of the night,
allowing for a better chance for snowfall accumulations. Snowfall
rates of 1-2"/hr over northern WI and the MI U.P. are also becoming
more likely per the 12z HREF, which will support greater
confidence in heavy snowfall accumulations over 4". Snowfall rates
and associated reduced visibilities are the expected hazards, along
with the potential for slippery overnight travel. Marquette's area
and the Huron Mts in particular will have better chances for heavy
accumulating snow as onshore, lake- enhanced snowfall ensues. Snow
tapers off Friday morning as the storm races north into Ontario.
WPC probabilities shows moderate chances (40-80%) for snowfall
totals >6" in MI's Huron Mountains into northern WI. There is also
the potential for light ice accumulations from northern IA and
southern MN to northern WI and the western MI U.P. during the onset
of the event with WPC probabilities showing moderate chances
(30-50%) for ice accumulations over one-hundreth of an inch. Ice
accumulation could occur near the evening rush hour in southern MN
and central WI.

...Central/Southern Rockies & Adjacent High Plains...
Day 1...

Following an initial shortwave ejecting into the Plains this
afternoon, a second and more vigorous upper level shortwave over
the Great Basin heads east for the Four Corners region tonight.
This system will bring with it not only additional Pacific moisture
but height falls, better PVA, and jet streak dynamics aloft.

As enhanced Q-vector convergence heads for the Front Range of the
Rockies and the High Plains this evening, a closed 700mb low will
develop over northern NM that gives rise to a surface low forming
in lee of the Sangre De Cristo mountains. Snow levels will quickly
fall below 5000ft by Friday morning. Meanwhile, low-level easterly
winds over the central High Plains fosters upslope flow into
southern CO and northern NM peaking Friday morning as the 700mb low
tracks just south of Raton Pass. There remains some latitudinal
disagreement on the placement of the best 700mb FGEN as the 700mb
low emerges into northeast NM and tracks towards the OK/TX
Panhandles. Where the best FGEN forcing sets up and the strength of
the 700mb low will be vital in where the heaviest snowfall occurs
and how far east away from the Raton Mesa and Front Range the band
of heavy snow can advance. Beneath the 700mb FGEN, >1"/hr snowfall
rates are expected. The 12z HREF and WPC Snowband Probability
Tracker depicts this well with 1"/hr snowfall rates possible
anywhere between southwest KS to the northern TX Panhandle. As the
700mb low moves northeast Friday afternoon, it will weaken and open
up into a progressive 500mb shortwave, resulting in frontolysis
over the High Plains that reduces precipitation rates and weakens
dynamic cooling aloft.

At this time, WPC probabilities are highlighting the usual
suspects (Palmer Divide, Front Range, Raton Mesa) as having
moderate-to- high chances (>70%) for snowfall totals >4". I-25 at
Raton Pass sports moderate-to-high chances (50-70%) for snowfall
totals >6". Localized snowfall totals >8" along the peaks of the
Sangre De Cristo and Raton Mesa are possible. Farther east, WPC
probabilities show high chances (60-90%) for snowfall totals >4" in
southeast CO, northeast NM, the far western OK Panhandle, and the
northwest tip of the TX Panhandle. The WSSI shows widespread Minor
Impacts (winter driving conditions; use caution when driving) for
much of the central High Plains with localized Moderate Impacts
possible over northeast NM.


...Great Lakes into the Northeast...
Days 2-3...

By Saturday night, the shortwave trough responsible for the heavy
snow in the the southern and central Rockies/High Plains tracks
eastward into the MS Valley. As this occurs, a deep, closed, 500mb
low in southern Canada plunges into the Upper Midwest and Great
Lakes. The latest guidance continues its recent trends of keeping
the much stronger northern stream disturbance separated just enough
to shear apart the southern shortwave instead of phasing together
with it. Given the overall system becoming more progressive due to
reduced phasing and less interaction between the better northern
stream dynamics and enhanced southern stream moisture, snow amounts
across eastern WI and northern MI have come down quite a bit with
this package. The latest WPC probabilities still show moderate to
high chances (50-75%) for snowfall amounts >4" across portions of
northern Michigan, but odds for >6" are now only 30-50%. The one
exception to that is across a small portion of the U.P. of Michigan
where some additional lake enhancement will give higher odds
(50-70%) of >6".

The same storm responsible for the snow over the northern Great
Lakes Saturday night into Sunday will also produce a hazardous
wintry mix across the northern Appalachians into northern New
England. The Northeast will lay ahead of a strong >750kg/m/s IVT
that will direct copious amounts of moisture northward Saturday
into Saturday night. At the same time, a cold front will provide
just enough cold/dry air at the surface with Canadian high pressure
to the north creating a weak CAD signature over the Northeast.
This healthy 850-700mb WAA will support a classic overrunning setup
of >0C air aloft causing a mixture of sleet/freezing rain to
unfold beginning Saturday afternoon and continuing into Saturday
night/early Sunday morning. Precipitation is looking more likely to
start out as snow farther north in northern New England Saturday
night, with the potential to stay all snow for a longer period of
time. This is due to secondary coastal development just south of
Long Island and Cape Cod, which may help to keep sub-freezing
surface temperatures entrenched. How long this colder air stays
locked in will go a long way in determining snow amounts there, and
if snow will eventually change to a wintry mix. Still, the greater
concern for frozen precipitation, whether it be freezing rain or
snow, is for many of the interior mountain ranges such as the
Catskills, Berkshires, Greens, Adirondacks, and Whites where
surface temperatures have better odds of staying sub-freezing
Saturday night and into Sunday morning. Once the secondary surface
low pressure takes over Sunday afternoon, most places across the
Northeast will end as snow as a strong cold frontal passage ushers
in a much colder air mass in its wake. Some of this snow will have
the potential to be moderate to heavy across parts of Maine,
pending additional coastal development.

The latest WPC probabilities indicate moderate chances (40-70%)
for minor ice accumulations over one-hundreth of an inch across the
Berkshires, Greens, Adirondacks, and Whites, with low chances
(10-30%) for ice greater than a tenth of an inch. In terms of snow,
WPC probabilities for >4" are moderate (40-70%) from the northern
Adirondacks, Greens, and Whites into northern Maine, with low
chances (10-30%) for 6 inches or more through Sunday evening.


Snell/Miller/Mullinax


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 090819
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
319 AM EST Fri Jan 9 2026

Valid 12Z Fri Jan 09 2026 - 12Z Mon Jan 12 2026


...Upper Midwest & Upper Great Lakes...
Day 1...

A swath of heavy/wet snow is ongoing along the western flank of a
storm system racing northeast through the Great Lakes. Snow bands
co-located beneath a classic 250mb jet coupling setup is
maximizing divergence atop the atmosphere at the same time
850-700mb FGEN support intense vertical velocities into a well
saturated DGZ. Boundary layer temperatures are marginally cold,
relaying heavily on the robust vertical velocities aloft and heavy
snowfall rates to keep the depth of the atmospheric column below
freezing. WPC's HREF Snowband Probability Tracker show the
potential for 1"/hr snowfall rates early this morning over
northern WI and the central MI U.P. that includes the Huron
Mountains. The latest forecast calls for 1-3" of snow over north-
central WI and into the heart of MI's U.P.. The Huron Mountains
have the best chances to see 4-6" of snowfall with localized totals
over 6" possible. WPC's WSSI shows largely Minor Impacts in these
areas, although localized Moderate Impacts (hazardous travel
conditions) are forecast around Marquette this morning. Snow tapers
off by midday as the storm races into southeast Canada.


...Central/Southern Rockies & Adjacent High Plains...
Day 1...

A vigorous upper level trough over the Four Corners region will
close off into a 500mb low this morning. This system will escort a
plume of Pacific moisture into the Rockies and central High
Plains. Subsequent PVA aloft and favorable jet streak dynamics will
work in tandem with easterly upsloping low-level winds to produce
heavy snow from the Palmer Divide and Sangre De Cristo to the Raton
Mesa and High Plains.

A closed 700mb low will develop over northern NM that gives rise
to a surface low forming in lee of the Sangre De Cristo mountains.
Snow levels will quickly fall below 5000ft by Friday morning, then
as the FGEN banding ensues over southwest KS, the OK Panhandle, and
the northern most counties of the TX Panhandle, snow levels will
fall to as low as 2,000ft during the day. Low-level easterly winds
over the central High Plains favors upslope flow into southern CO
and northern NM peaking early this morning as the 700mb low tracks
just south of Raton Pass. Where the best FGEN forcing sets up and
the strength of the 700mb low will be vital in where the heaviest
snowfall occurs and how far east away from the Raton Mesa and Front
Range the band of heavy snow can advance. Beneath the 700mb FGEN,

1"/hr snowfall rates are expected. The latest HREF and WPC

Snowband Probability Tracker depicts this well with 1"/hr snowfall
rates possible anywhere between the Sangre De Cristo and Raton Mesa
to the TX/OK Panhandles and southwest KS. As the 700mb low moves
northeast Friday afternoon, it will weaken and open up into a
progressive 500mb shortwave, resulting in frontolysis over the High
Plains that diminishes precipitation rates and weakens dynamic
cooling aloft.

Recent 12-24 hour trends have been snowier in the High Plains as
far east as southwest KS thanks to the 700mb low remaining in tact
longer as it tracks east. The latest snowfall forecast calls for
anywhere from 6-12" of snow from the Front Range as far north as
Pikes Peak on south along the Sangre De Cristo and into Raton Mesa.
Given the recent trends for heavier snowfall protruding as far east
as southwest KS, snowfall totals of 4-8" (localized totals >8")
are likely in southeast CO, southwest KS, the OK Panhandle, and the
far northwest reaches of the TX Panhandle. The WSSI is showing a
larger swath of Moderate Impacts in these aforementioned areas
with localized Major Impacts highlighted along the Raton Mesa and
very close to I-25's Raton Pass.


...Great Lakes into the Northeast...
Days 2-3...

The shortwave trough responsible for the heavy snow in the the
southern and central Rockies/High Plains tracks eastward into the
MS Valley Saturday night. Farther north, a closed 500mb low in
southern Canada plunges into the Upper Midwest and Great Lakes. As
low pressure deepens over Lake Huron Saturday night, a deformation
zone of snow will envelope the northern Great Lakes. The focus for
heavy snow will be beneath the developing TROWAL that looks to
setup over the U.P. of Michigan. Over the past 24 hours, guidance
has trended more progressive with the storm system and its
associated TROWAL, which has continued the trend of gradually
decreasing snowfall totals. Latest WPC probabilities still show
moderate to high chances (50-75%) for snowfall amounts >4" in the
Porcupine and Huron Mountains of Michigan's U.P., as well as the
norther tier of Michigan's L.P.. Most odds for >6" of snowfall
remain in the 30-50% range, but the Huron Mountains and the tip of
Michigan's Mitten would be most favored for localized snowfall
totals over 8" given additional lake-enhanced snowfall there.

The same storm responsible for the snow over the northern Great
Lakes Saturday night into Sunday will also produce a hazardous
wintry mix across the interior Northeast and heavy snow in northern
New England. A strong >750kg/m/s IVT will direct copious amounts
of moisture northward Saturday into Saturday night. At the same
time, a cold front will inject just enough cold/dry air at the
surface with Canadian high pressure to the north creating a weak
CAD signature over the Northeast. This healthy 850-700mb WAA will
support a classic overrunning setup of >0C air aloft causing a
mixture of sleet/freezing rain to unfold beginning Saturday
afternoon and continuing into Saturday night/early Sunday morning.
Guidance has trended weaker with the primary low over southeast
Canada Saturday night, and with a developing secondary coastal low
near southern New England, the expectation is for sub-freezing
surface temperatures to persist longer. One potential issue for
snow in northern New England is the potential for a 700-300mb dry
slot that could sap moisture in the DGZ aloft over northern NY and
northern VT/NH.

Still, whether it is ice or snow, many of the interior mountain
ranges such as the Catskills, Berkshires, Greens, Adirondacks, and
Whites are favored to see the heaviest wintry precipitation Saturday
night and into Sunday. As the coastal low takes over on Sunday,
lake-effect snow showers are likely to continue down wind of Lakes
Erie and Ontario while northern Maine would be more likely to see
periods of heavy snow. WPC probabilities indicate moderate chances
(40-70%) for minor ice accumulations over one- hundreth of an inch
across the Berkshires, Greens, Adirondacks, and Whites, with low
chances (10-30%) for ice greater than a tenth of an inch in the
Adirondacks. Regarding snowfall, WPC probabilities for >4" are
moderate (40-70%) over the White Mountains and northern Maine.
Northern Maine has the best chances for witnessing locally heavy
snowfall with low chance probabilities (10-30%) for snowfall totals

8". With lake enhanced snowfall possible in wake of a cold

frontal passage on Sunday, the Tug Hill and Chautauqua Ridge are
sporting moderate-to-high chances (50-80%) for localized snowfall
totals >4" through Sunday night.


Mullinax



$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 091959
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
259 PM EST Fri Jan 9 2026

Valid 00Z Sat Jan 10 2026 - 00Z Tue Jan 13 2026


...Central/Southern Plains...
Day 1...

Closed low exiting the CO Plains this afternoon will continue to
weaken as it moves eastward. Snow will diminish in coverage after
00Z but some light accumulation is possible through Kansas and into
Missouri.


...Great Lakes...
Days 1-3...

Shortwave exiting the Plains will combine with a stronger forming
closed mid-level low plunging southeastward out of south central
Canada tomorrow morning, favoring surface low development over
Lower Michigan. A deformation zone of snow will envelope the
northern Great Lakes with a focus for at least some brief heavy
snow beneath the developing TROWAL that sets up over the U.P. of
Michigan. The surface low is forecast to pull into Ontario Sunday
morning, gradually ending the synoptic snow for Michigan with a
short lake-enhanced/effect period of snow. On its heels will be
another Canadian shortwave Sunday evening through Monday morning
with only light snow of around an inch. WPC probabilities for at
least 4 inches of snow with the lead system this weekend are around
50% in the Porcupine and Huron Mountains in the U.P. and
northwestern Lower Michigan. Three-day totals could eclipse 8
inches in favored areas (30-50% chance).

Fracasso


...Northeast & Central Appalachians...
Days 1-3...

The same storm responsible for the snow over the northern Great
Lakes Saturday night into Sunday will also produce a hazardous
wintry mix across the interior Northeast and heavy snow in northern
New England. A strong >750kg/m/s IVT will direct copious amounts
of moisture northward Saturday into Saturday night along the
Northeast coastline. At the same time, a cold front will inject
just enough cold/dry air at the surface with Canadian high pressure
to the north creating a weak CAD signature over the Northeast.
This healthy 850-700mb WAA will support a classic overrunning setup
of >0C air aloft causing a mixture of sleet/freezing rain to
unfold beginning Saturday afternoon and continuing into Saturday
night/early Sunday morning. Guidance has trended weaker with the
primary low over southeast Canada Saturday night, and with a
developing secondary coastal low near southern New England, the
expectation is for sub- freezing surface temperatures to persist
longer. One potential issue for heavier snow in northern New
England is the potential for a 700-300mb dry slot that could sap
moisture in the DGZ aloft over northern NY and northern VT/NH.
Thus, the main hazard outside of far northern New England or Maine,
is expected to be associated with freezing rain.

Still, whether it is ice or snow, many of the interior mountain
ranges such as the Catskills, Berkshires, Greens, Adirondacks, and
Whites are favored to see the heaviest wintry precipitation
Saturday night and into Sunday. As the coastal low takes over on
Sunday, lake-effect snow showers are likely to continue down wind
of Lakes Erie and Ontario while northern Maine would be more likely
to see extended periods of moderate snowfall through Sunday night.
WPC probabilities indicate moderate chances (60-80%) for minor ice accumulations over a tenth of an inch across the Berkshires,
Greens, Adirondacks, and Whites and have increased with this
forecast iteration. Low chances (10-20%) for ice greater than a
quarter of an inch in the Adirondacks and southern
Greens/Berkshires. Regarding snowfall, WPC probabilities for >4"
are moderate- (70-90%) over the northern Green/White Mountains and
northern Maine. Northern Maine has the best chances for witnessing
locally heavy snowfall with low chance probabilities (10-30%) for
snowfall totals >8". With lake enhanced snowfall possible in wake
of a cold frontal passage on Sunday, the Tug Hill and Chautauqua
Ridge are sporting moderate-to- high chances (50-80%) for localized
snowfall totals >4" through Sunday night.

Additionally, as strong height falls cross the Ohio Valley
Saturday night before impacting the central Appalachians and Mid-
Atlantic on Sunday, snow squalls and upslope-enhanced snowfall is
likely. A coating to an inch of snow is possible within isolated to
scattered snow squalls as they swing from the Ohio Valley into the Mid-Atlantic, with more snow likely in the central Appalachians.
WPC probabilities for >4" are 20-50% across the Alleghenies of
western MD and WV.


Snell


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 100814
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
314 AM EST Sat Jan 10 2026

Valid 12Z Sat Jan 10 2026 - 12Z Tue Jan 13 2026


...Great Lakes...
Days 1-3...

An upper-level low over northern MN this morning will project
healthy PVA over the Great Lakes, as well as strong 700mb Q-vector
convergence over northern MI and MI's Upper Peninsula (U.P.). A
plume of 700-300mb moisture wrapping around the northern flank of
the 700mb low will coincide within a TROWAL that focuses a band of moderate-to-heavy snow over the northern Great Lakes. The storm
system will progress east into southern Ontario by Sunday morning
and snow will begin to taper off by late Sunday morning. Most
guidance shows anywhere from 4-8" of snowfall as far west as the
Porcupine Mountains of MI's western U.P. to the Hurons in the heart
of the U.P. and much of the eastern U.P.. Farther south, the
northern-most locations of Michigan's Mitten are forecast to
receive 4-8" of snowfall as well, with localized totals topping 10"
possible where lake-enhanced snow bands stick around longest. Snow
fall totals of 1-4" are also anticipated along the coast of WI and
the western most counties of MI. The WSSI shows Minor Impacts
across all these regions, suggesting residents are likely to
contend with hazardous travel conditions Saturday night and into
Sunday morning.

In wake of this storm system, two more Canadian clipper systems
will race towards the Great Lakes. The first brings light snowfall
to northern MN Sunday afternoon and then into the northern Great
Lakes Sunday night. It is moisture starved and progressive, so
totals will generally range between a coating-3". As that upper-
level shortwave trough heads for the Northeast on Monday, another
clipper over the Canadian Prairies will track into the Upper
Midwest Monday night. This system has a little more moisture to
work with, but boundary layer temperatures are milder and may
result in more of a snow/rain mix on Tuesday. Both wintry setups
will be closely monitored, but snowfall totals are likely to
produce minor snowfall totals rather than highly impactful amounts
at this time.


...Northeast, Ohio Valley, & Central Appalachians...
Days 1-3...

On the eastern flank of the approaching Great Lakes storm system, a
strong IVT topping 750 kg/m/s and an advancing 925-700mb WAA will
provide rich moisture and strong low-level forcing to produce
periods of snow and a wintry mix over the interior Northeast.
Freezing rain will be most common today in northern PA, the
Poconos, Catskills, Adirondacks, Berkshires, and Green Mountains.
Latest WPC probabilities show moderate chancres (40-60%) for ice
accumulations over one-tenth of an inch in the Adirondacks, Greens,
and Berkshires, whereas the rest of the listed areas are generally
expected to witness ice accumulations less than one-tenth. Farther
north, snow will be the more common precipitation type from the
northern Adirondacks and White Mountains through northern Maine.
This is due to their locations farther north of the storm track of
the primary low in Ontario, and their placement north of a
secondary coastal low in the Gulf of Maine. The coastal low will
deepen southwest of Nova Scotia on Sunday and support a
deformation zone of heavy snow over northern Maine through Sunday
night. Snow should finally taper off by Monday morning, although
some blowing snow may still be ongoing across Maine. WPC
probabilities show high chances (>70%) for snowfall totals >6" in
northern Maine with low chances (10-30%) for some localized areas
near Caribou that could receive as much as a foot of snow.

This storm system over the Great Lakes will also be responsible for
other winter related hazards over the Ohio Valley and central
Appalachians. Ahead of an approaching 500mb vort max, a sharp low-
level cold front and healthy PVA aloft will support the development
of snow squalls Saturday afternoon as far west as Iowa that race
east towards northern IL and IN Saturday evening. Snow squalls will
race east through the OH Valley Saturday night and reach the Upper
OH Valley and central Appalachians by early Sunday morning. Light
accumulations of a coating to 1" are possible, but the concern is
rapid reductions in visibilities due to a combination of heavy snow
rates and gusty winds. Surface temperatures will also plummet below
freezing and could support quickly accumulating snowfall on roads.
Motorists should ensure they have a way to receive alerts for snow
squall warnings should they be issued.

Meanwhile, as the aforementioned cold front and snow squalls reach
the central Appalachians Sunday morning, upslope NWrly flow will
foster heavy mountains snow in the Potomac and Laurel Highlands
Sunday and into Sunday night. WPC probabilities show moderate-to-
high chances for snowfall totals >2", but there is a lower chance
scenario (10-30%) where the peaks of the Appalachians in eastern WV
and western MD receive as much as 4-6" of snow. Lastly, westerly
flow off Lakes Erie and Ontario will trigger lake effect snow bands
over the Chautauqua Ridge and over the Tug Hill Plateau Sunday and
into Sunday night. WPC probabilities depict moderate-to-high
chances for snowfall >4" through Sunday night. There will be
another chance for additional light snow over the Adirondacks and
Whites on Monday, but aside from the Tug Hill, snowfall will
generally be between a coating to 2" through early Tuesday morning.


Mullinax



$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 101934
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
234 PM EST Sat Jan 10 2026

Valid 00Z Sun Jan 11 2026 - 00Z Wed Jan 14 2026


...Great Lakes...
Days 1-2...

An upper-level low over northern WI this evening will project
healthy PVA over the Great Lakes, as well as strong 700mb Q-vector
convergence over northern MI and MI's Upper Peninsula (U.P.). A
plume of 700-300mb moisture wrapping around the northern flank of
the 700mb low will coincide within a TROWAL that focuses a band of moderate-to-heavy snow over the northern Great Lakes. The storm
system will progress east into southern Ontario by Sunday morning
and snow will begin to taper off by late Sunday morning, but with lake-effect/enhanced snow continuing early Sunday as a brief surge
of northerly flow affects the region. Most guidance shows anywhere
from 4-8" of snowfall as far west as the Porcupine Mountains of
MI's western U.P. to the Hurons in the heart of the U.P. and much
of the eastern U.P.. Farther south, the northern-most locations of
Michigan's Mitten are forecast to receive 4-8" of snowfall as well,
with localized totals topping 10" possible where lake-enhanced
snow bands stick around longest. Snow fall totals of 1-4" are also
anticipated along the coast of WI and the western most counties of
MI. The WSSI shows Minor Impacts across all these regions,
suggesting residents are likely to contend with hazardous travel
conditions tonight and into Sunday morning.

Lastly, westerly flow off Lakes Erie and Ontario will trigger lake
effect snow bands over the Chautauqua Ridge and over the Tug Hill
Plateau Sunday and into Sunday night. WPC probabilities depict
moderate-to- high chances for snowfall >4" through Sunday night.
There will be another chance for additional light snow over the
Adirondacks and Whites on Monday, but aside from the Tug Hill where
up to 6" is possible, snowfall will generally be between a coating
to 2" through early Tuesday morning.


...Northeast...
Days 1-2...

On the eastern flank of the approaching Great Lakes storm system, a
strong IVT topping 750 kg/m/s and an advancing 925-700mb WAA will
provide rich moisture and strong low-level forcing to produce
periods of snow and a wintry mix over the interior Northeast and
New England. Freezing rain will be most common through tonight in
the Poconos, Catskills, Adirondacks, Berkshires, and Green
Mountains. Latest WPC probabilities show moderate chancres (40-60%)
for ice accumulations over one-tenth of an inch in the
Adirondacks, Greens, and Berkshires, whereas the rest of the listed
areas are generally expected to witness ice accumulations less
than one-tenth. Farther north, snow will be the more common
precipitation type from the northern Adirondacks and White
Mountains through northern Maine. This is due to their locations
farther north of the storm track of the primary low in Ontario, and
their placement north of a secondary coastal low in the Gulf of
Maine. The coastal low will deepen southwest of Nova Scotia on
Sunday and support a deformation zone of heavy snow over northern
Maine through Sunday night. Snow should finally taper off by Monday
morning, although some blowing snow may still be ongoing across
Maine. WPC probabilities show high chances (60-80%) for snowfall
totals >6" in northern Maine with low chances (10-30%) for some
localized areas near Caribou that could receive as much as a foot
of snow. Still, given the climatology of snowfall across these
northern locations, only Minor Impacts are being depicted from the
WSSI.


...Ohio Valley & Central Appalachians...
Days 1-2...

This storm system over the Great Lakes will also be responsible for
other winter related hazards over the Ohio Valley and central
Appalachians. Ahead of an approaching 500mb vort max, a sharp low-
level cold front and healthy PVA aloft will support the development
of snow squalls beginning this afternoon as far west as Iowa that
race east towards northern IL and IN this evening. Snow squalls
will race east through the OH Valley tonight and reach the Upper
OH Valley and central Appalachians by early Sunday morning per the
12z CAMs and forecast snow squall parameters. Light accumulations
of a coating to 1" are possible, but the concern is rapid
reductions in visibilities due to a combination of heavy snow rates
and gusty winds. Surface temperatures will also plummet below
freezing and could support quickly accumulating snowfall and a
flash freeze on roads. Some snow squalls may also reach past the
terrain of the central Appalachians and into the Mid-
Atlantic/Interior Northeast Sunday afternoon. Motorists should
ensure they have a way to receive alerts for snow squall warnings
should they be issued and understand the risks of driving during a
snow squall.

Meanwhile, as the aforementioned cold front and snow squalls reach
the central Appalachians Sunday morning, upslope NWrly flow will
foster heavy mountains snow in the Potomac and Laurel Highlands
Sunday and into Sunday night. WPC probabilities show moderate-to-
high chances (40-70%) for snowfall totals >4". Lastly, westerly
flow off Lakes Erie and Ontario will trigger lake effect snow bands
over the Chautauqua Ridge and over the Tug Hill Plateau Sunday and
into Sunday night. WPC probabilities depict moderate-to- high
chances for snowfall >4" through Sunday night. There will be
another chance for additional light snow over the Adirondacks and
Whites on Monday, but aside from the Tug Hill, snowfall will
generally be between a coating to 2" through early Tuesday morning.


Snell/Mullinax



$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 110812
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
312 AM EST Sun Jan 11 2026

Valid 12Z Sun Jan 11 2026 - 12Z Wed Jan 14 2026


...Ohio Valley, Central Appalachians, & Mid-Atlantic...
Day 1...

Snow squalls are continuing to race east across the Upper OH Valley
this morning that will soon track into the central Appalachians and
northern Mid-Atlantic this afternoon. Snowfall totals will
most likely only resulting in a dusting, although some localized
totals up to 1" are possible. Farther north, snow squalls are also
possible across Upstate NY where the base of a 500mb low and
falling heights will tap into some Great Lakes moisture to trigger
rounds of snow squalls. Despite the minor amounts, rapid
accumulations on all surfaces can occur as temperatures in wake of
the cold frontal passage rapidly fall. Plus, bursts of snow and
gusty winds would lead to dramatic changes from clear visibility to
near whiteout conditions. Residents in these areas should be sure
to monitor any squalls and be on the lookout for any snow squall
warnings as they traverse these regions today. Snow squalls should
taper off by Sunday evening northeast PA and the Lower Hudson
Valley.

The heaviest snowfall will occur in the central Appalachians where
NWrly upslope flow generates enhanced snowfall rates in the Laurel
and Potomac Highlands. High pressure over the MS Valley will
quickly build in Sunday evening and snow should taper off by early
Monday morning. WPC probabilities show moderate-to-high chances
(50-80%) for snowfall totals >4" in the >2,000ft peaks of eastern
WV, while western MD and the Laurel Highlands are most likely to
receive anywhere from 1-4" of snowfall. The WSSI shows Minor Impact
potential, suggesting hazardous travel conditions are likely in
affected areas.


...Great Lakes...
Days 1 & 3...

Cyclonic flow on the western flank of the departing storm system
over southeast Canada will keep some residual lake-enhanced snow
showers over the Michigan U.P. and Michigan's L.P.. As snow tapers
off over Michigan Sunday afternoon, the heaviest snow will unfold
along the Chautauqua Ridge of PA/NY and down wind of Lake Ontario.
Lake effect snow bands will weaken as the pressure gradient. WPC
probabilities show moderate chances (40-60%) for snowfall totals

4" along the Chautauqua Ridge, while snowfall lingers longest over

the Tug Hill thanks their more favorable position east of a fast
moving 500mb vorticity maximum. WPC 48-hour probabilities (through
Monday night) depict the Tug Hill Plateau with high chances (>70%)
for snowfall totals >8" with some locations likely receiving over a
foot of snow.

Following a brief lull in snow on Monday, focus turns to Tuesday as
an amplifying shortwave trough in south-central Canada dives south
towards the Upper Midwest late Tuesday and into Wednesday. A
deepening clipper over Lake Superior will accompany an Arctic front
that races south over the Michigan U.P. Tuesday night. Strong low-
level CAA looks to reinvigorate the lake effect snow machine over
northern WI, the Michigan U.P., and the tip of Michigan's Mitt.
Latest WPC probabilities show low-to-moderate chances (30-50%) for
snowfall totals over 4" in the Porcupine and Huron Mountains of the
Michigan U.P., with a broader footprint of moderate chance
probabilities (40-70%) for snowfall >2" from northern WI on east
to the the eastern Michigan U.P.. The western Michigan U.P. does
feature the best chances for locally heavier totals, depicted by
low-chance probabilities (10-30%) in the Porcupine and Huron
mountains, as well as the Keweenaw Peninsula. The WSSI-P does show low-to-moderate chances (20-50%) for Minor Impacts over these
aforementioned areas Tuesday night and into Wednesday morning.


...Northern New England...
Day 1...

As the primary storm system over southeast Canada weakens and the
coastal low forms over the Gulf of Maine, periods of snow will
continue over northern Maine and the Whites through Sunday. Rates
will lessen this afternoon and evening, but lingering cyclonic flow
on the backside of the coastal storm (located north of Nova Scotia
by Sunday night) will keep snow in the forecast Sunday night. Snow
tapers off by Monday morning, leaving a swath of 6-12" of snowfall
over northern Maine. Farther south, additional ice accumulations
under a tenth of an inch are anticipated over Downeast Maine and
just north of the Maine coast. The WSSI depicts Minor Impacts over
northern Maine, highlighting the likelihood of hazardous travel
conditions. A pair of progressive shortwave troughs will bring some
additional light snow over the Adirondacks, Greens, Whites, and
northern Maine Monday and Tuesday but latest guidance shows
generally a coating-2" for these mountain ranges and northern Maine
through Tuesday night with some localized amounts approaching 4"
possible in the peaks of the Adirondacks.


Mullinax






$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 111942
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
242 PM EST Sun Jan 11 2026

Valid 00Z Mon Jan 12 2026 - 00Z Thu Jan 15 2026


...Central Appalachians...
Day 1...

Snow squalls are expected to wane by this evening over the Mid-
Atlantic as the associated cold front exits into the eastern
Atlantic Ocean and lapse rates weaken following sunset. Upslope
northwesterly flow into the terrain of the central Appalachians may
continue to produce moderate snowfall until early Monday morning
when this flow eventually weakens and dries out due to a more
westerly component to the winds. A few inches of additional
snowfall are likely across the Allegheny Mts of WV, western MD, and
southwest PA.


...Great Lakes & Northern New England...
Days 1-3...

Deep upper trough and attached closed low starts the period over
New England with an associated rapidly deepening surface low
quickly exiting towards Newfoundland. Lingering light to moderate
snowfall is possible tonight along with increasing winds across far
northern ME due to this area of low pressure. Latest WSSI depicts
Minor Impacts through tonight due to this continuing snowfall.

Meanwhile, cold northwesterly flow will weaken on Monday over the
Great Lakes and northern New England as an embedded shortwave
crosses the region with additional light snow downwind of Lake
Ontario and into the favorable upslope terrain of the Adirondacks,
northern Greens and Whites. Then by Tuesday a much stronger
shortwave and area of low pressure is expected to pass over or just
to the north of the Great Lakes. Initial WAA snow is possible over
the Upper Great Lakes Tuesday morning along with a glaze of
freezing rain, but snow and ice amounts are expected to remain
light. As this system exits to the east on Wednesday and upper
troughing deepens over the Great Lakes as well as increasing
northerly CAA, lake effect snow is forecast to pick up once again
along the shores of Lake Superior in the U.P. of MI.

For the entire period snowfall totals are expected to remain
mostly light outside of the Tug Hill Plateau and favorable
snowbelts in the U.P. of MI. WPC probabilities for over 8" of snow
through 00Z Thursday are 50-70% in the Tug Hill and 20-50% in the
MI U.P. from the Porcupine to Huron Mts.


Snell


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 120808
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
308 AM EST Mon Jan 12 2026

Valid 12Z Mon Jan 12 2026 - 12Z Thu Jan 15 2026


...Great Lakes...
Days 1-3...

Ongoing westerly flow over Lake Ontario will keep additional heavy
snowfall of 6-12" in the forecast today over the Tug Hill Plateau,
while minor amounts generally between 1-4" occurs around the
Buffalo area and the Adirondacks. By tonight, a Canadian clipper
system will race east over southern Ontario with just enough low-
level WAA and a plume of 700-300mb moisture aloft to support a
brief overrunning setup over the MN Arrowhead, northern WI, and the
western MI U.P.. Ice accumulations are likely to be less than a
tenth of an inch, but WPC probabilities show moderate chances

50%) for ice accumulations over on-ehundreth of an inch. Slick

spots on untreated surfaces are possible Monday night and into
Tuesday morning in affected areas.

As the clipper continues to advance east into southeast Canada, a
robust 500mb vorticity max diving south will accompany a strong
cold front that induces strong CAA over Lake Superior Tuesday
night. Snow will increase in intensity over the Michigan U.P. as
surface-850mb delta Ts dramatically increase and low-level lapse
rates sharpen. The upper-level trough continues to dive south
through the Great Lakes on Wednesday and the same CAA regime will
race south over Lake Michigan. Guidance is coming into better
agreement on the formation of a potent single-band LES setup
producing a swath of heavy snow over northwest IN that could
oscillate at times to as far west as the WI/IL lake shores and as
far east as southwest MI. Meanwhile, much of Michigan's Mitten will
contend with multi-band lake effect streamers as a surface trough
pivots over the Great Lakes Wednesday and into Wednesday night.
This same trough axis, along with the CAA over the Great Lakes,
will trigger lake-enhanced snowfall over northern OH, northwest PA,
and western NY by early Thursday morning. Snowfall will become
more synoptically-enhanced by early Thursday morning as a 700mb low
tracks over Lake Erie and would support heavy snowfall into the
day on Thursday as well.

24-hour WPC probabilities through 12Z Wednesday show
moderate chances (40-60%) for snowfall totals >6" along the
Keweenaw Peninsula and both the Huron and Porcupine Mountains of
the MI U.P.. 24-hour probabilities through 12Z Thursday depict
northwest IN as having moderate chances (40-60%) for snowfall
totals >6". Note that should 1-2"/hr rates materialize, localized
amounts approaching a foot of snow are possible. Lastly, through
12z Thursday, the first 6-12 hours of the impending winter storm
show low chances (10-30%) for snowfall totals >4", but with the
storm likely to produce additional heavy snow along the Chautauqua
Ridge and into western NY, expect heavier snowfall totals to
envelop these areas through Thursday. The WSSI-P currently shows moderate-to-high chances (50-70%) for at least Minor Impacts over
northwest IN, northeast OH, and western NY through Thursday
morning.

...Upper Ohio Valley, Central Appalachians, & Northeast...
Days 3-3.5...

A robust 500mb shortwave trough over the Upper Midwest will race
southeast toward the Ohio Valley Wednesday night. There remains a
fair amount of uncertainty and model spread that is making this
forecast tough in the Ohio Valley and as far east as the I-95
corridor, but the higher confidence areas are the spine of the
Appalachians. As the 500mb shortwave deepens into a closed upper
low Wednesday night, an accompanying strong cold front will
collide with the central Appalachians with strong 925-700mb layer
CAA. The combination of brisk NWrly flow and excellent PVA aloft
ahead of the upper low will produce heavy snowfall rates from the
Laurel Highlands of southern PA on south to the Blue Ridge and
Smokey Mountains. Snow is likely to continue beyond the scope of
this short-term discussion as cyclonic flow around the western
flank of the storm system sustains favorable upslope flow into the
central Appalachians. The WSSI-P is showing >50% chances for a
at least Minor Impacts over the Smokeys of TN/NC, and both the
windward slopes and peaks of the central Appalachians. Residents
and travelers should plan for a disruptive snow event in central
Appalachians Wednesday evening and into Thursday.

From the Ohio Valley on north through western PA and into the
Northeast the forecast is more murky. Guidance across the board
shows different evolutions and tracks of the aforementioned 500mb
low. The CMC shows a lack of deepening/phasing of 500mb vort
maxima that keeps the synoptic-scale forcing limited. The ECMWF/EC-
AIFS/UKMET camps show a closed low by tracking across the lower
Great Lakes and into the Northeast. To illustrate the ongoing
changes, the 00Z ECMWF from 24 hours ago had a closed low south of
Louisville, KY by 12Z Thursday, while the latest 00Z ECMWF has the
closed low near Cleveland, OH at the same time Thursday. Lastly,
the GFS/GEFS is farther south over the OH Valley that then heads
for the Mid-Atlantic coast as a weakening closed low. All these
evolutions lead to different snowfall footprints, particularly
along the I-95 corridor and northern Mid-Atlantic. No matter the
track of the upper-low, the meteorology involved supports periods
of snow north of the emerging 700mb low. The EPS/GEFS both show the
left-exit region of a strengthening jet streak off the southeast
coast being placed over the Northeast, which also pairs favorably
with 700mb Q-vector convergence on both GFS and ECMWF solutions
over the eastern Great Lakes and interior Northeast. Through 12Z
Thursday, WPC probabilities show northern OH (including the
Cleveland metro) on north and east along the Chautauqua Ridge and
the Adirondacks showing low-to-moderate chances (30-50%) for >4" of
snowfall.

Residents and travelers across the Northeast will want to monitor
the forecast closely in the coming days as this complex forecast is
likely to change in the coming days. The lowest confidence in terms
of snowfall amounts and impacts are along the I-95 corridor as
potential scenarios range from a significant winter storm for areas
along I-95 in southern New England to minor snow accumulations at
most depending upon the strength and track of the approaching
upper-low. Not only are amounts unclear, but boundary layer
temperatures at the onset Wednesday night and early Thursday
morning would support rain as the initial precipitation type before
changing over to snow. For now, the spine of the Appalachians are
favored to see accumulating snowfall late Wednesday into Thursday.


Mullinax





$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 121909
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
209 PM EST Mon Jan 12 2026

Valid 00Z Tue Jan 13 2026 - 00Z Fri Jan 16 2026


...Great Lakes...
Days 1-3...

Slowly amplifying flow across the east will result in periods of
light synoptic snow, and more impressive lake effect snow (LES)
through the period.

Tonight, a surface trough will track rapidly eastward across the
eastern Great Lakes and into New England while weakening. Although
this feature is progressive and of modest intensity, the enhanced south-westerly flow in its wake will help spawn LES, especially
downwind of Lakes Erie and Ontario through Tuesday morning. Slowly
rising heights within shortwave ridging Tuesday morning will bring
a quick end to this LES, but at least briefly heavy snow rates of
1"/hr (10-20% chance) will produce significant accumulations,
especially in the Tug Hill Plateau where WPC probabilities are
moderate (50-70%) for at least 4" of snow.

Thereafter, a series of fast-moving shortwave troughs will track
southeast downstream of an amplifying ridge across the western
CONUS. This will lead to a gradually deepening trough in the east,
with increasing cold advection within impressive cyclonic flow. The
first of these shortwaves will track across MI and into northern
New England late D1 into D2, pushing a surface low along the
US/Canada border through Wednesday. Some modest WAA will spread
light synoptically forced snow from WI into MI, but with only
modest accumulations.

More impressively, this low will drag an arctic cold front
southward behind it, aided by a secondary impulse which will track
towards the Gulf Coast helping to deepen the longwave trough with a
closed low over the Great Lakes. While there has been a lot of
uncertainty and latitudinal changes with this evolution the past
few model runs, impressive CAA behind this front will result in
impressive LES, especially in the north-wind lake effect belts
across the U.P., northern L.P., and south of Lake Michigan, with
additional LES likely into northeast Ohio and the Chautauqua Ridge
during D3. WPC probabilities for more than 4" of snow D2 reach
50-70% for parts of the U.P., and then expand to southeast of Lakes
Erie and Ontario D3, with the most significant snowfall likely in a
single band southeast of Lake Michigan (with possible Lake Superior
connection) across northern IN where 8+ inches of snow is possible
(30-50% chance).


...Central Appalachians through the Northeast...
Day 3...

Amplification of the mid-level pattern through Thursday will result
in an anomalous trough digging across the eastern CONUS, reflected
by NAEFS 500-700mb heights falling below the 0.5 percentile across
portions of the Mid-South and Southeast before 00Z Friday. While
this trough is impressive, there has been considerable variability
over the past several model cycles both in terms of the intensity
and placement of the core of this trough, most notably with the
position of the closed low likely to develop Thursday morning.

This closed low will manifest from a deepening shortwave tracking
almost due south out of Manitoba, while secondary energy rotates
towards the Gulf Coast. Together, these will amplify the trough as
noted above, with the lead shortwave closing off and forcing a
slightly negative tilt by the end of the forecast period. At the
same time, a powerful jet streak will arc increasingly poleward
over the Atlantic (downstream of this trough axis) to provide
intense left-exit diffluence overlapping the impressive mid-level
height falls and divergence. While this should support a deepening
surface low pressure, guidance has systematically backed off on the
intensity and southern latitude of this low, with any secondary low
development occurring too far east to bring heavy
snowfall/precipitation to the east coast despite the lead low
moving across northern New England.

The cluster analysis (00z/11 cycle) indicates that the GEFS is
likely underdispersive into D4 as 77% of its members make up one
cluster, which is also the most amplified and slowest due to
extremely different ridging intensity over northern Ontario. While
this solution can't be ruled out entirely, the trend in the GFS
heights combined with the more broad solution envelope of the other
ensembles indicates the more likely scenario is for a low pressure
moving through New England Thursday, with modest warm air aloft
(TROWAL) pivoting behind this low coincident with weak deformation
atop an inverted trough supporting heavier snow generally from
Lake Erie through northern New England. This robust ascent may
overlap effectively with a deepening DGZ as well, with the cold
column supporting fluffy SLR that can accumulate rapidly. While
confidence remains lower than usual at this time range, current WPC probabilities are moderate to high (50-90%) for at least 4" of
snow in the vicinity of Lake Ontario and northeast into the St.
Lawrence Valley and parts of the Adirondacks.

Farther southwest, there is higher confidence in brief but
impressive upslope snow behind the arctic front on Thursday.
Forecast soundings indicate a deepening PBL with theta-e lapse
rates around 0C/km, coincident with impressive ascent into the DGZ
and then lifting into the terrain, especially from the Laurel
Highlands south into the Southern Appalachians. Initially some of
this precipitation may be rain, but will quickly dynamically cool
(and thermally cool behind the front) leading to periods of heavy
snowfall beginning early Thursday and persisting through much of
D3. WPC probabilities have dropped a bit as QPF trends have been
more to the north, but still indicate a 30-50% chance for at least
4" of snow across the higher terrain of WV, with high probabilities

70% or more) for 2+ inches along most of the Appalachians from SW

NC through the Laurel Highlands of PA.


Weiss


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 130808
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
308 AM EST Tue Jan 13 2026

Valid 12Z Tue Jan 13 2026 - 12Z Fri Jan 16 2026


...Great Lakes...
Days 1-3...

After a day of light snow across the Upper Great Lakes today thanks
to a Canadian clipper racing east across southern Ontario, a more
potent 500mb shortwave trough with an accompanying arctic cold
front will reinvigorate the lake-effect snow machine starting
tonight. Robust CAA in wake of the arctic front will result
numerous multi-banded streamers, especially over the northern half
of the U.P., northern and western L.P., and south of Lake
Michigan. Additional LES bands are likely over northeast Ohio, the
Chautauqua Ridge, and as far north as the Tug Hill late Wednesday
and through Thursday. The heaviest totals will be found over
northwest IN and far southwest MI where there is high confidence in
a potent single-band of LES that is likely to generate 1-2"/hr
snowfall rates. WPC probabilities show moderate-to-high chances
(50-70%) for snowfall totals >6" in northwest IN with lower chances
(10-30%) for amounts exceeding 8". Given the intense mesoscale
forcing at play, seeing some localized amounts approaching 12"
cannot be ruled out. WPC's WSSI does depict Moderate Impact
potential in the hardest hit areas of northwest IN which could
result in delays and/or closures along I-94 and I-80.

Elsewhere, WPC probabilities show high chances (>70%) for over 4"
of snow across much of the U.P., while western MI (including
Traverse City) show moderate chances (>50%) for over 4 of snowfall.
For Wednesday and through Thursday, moderate-to-high chances
(50-70%) for snowfall >4" are depicted over northeast OH, the
Chautauqua Ridge, and the Tug Hull Plateau. Some areas along the
Chautauqua Ridge and Tug Hill could top 8" and localized amounts
approaching 12" are possible.


...Central Appalachians through the Northeast...
Days 2-3...

Over the past 12-24 hours, guidance has continued to trend farther
north with the track of the 500mb low traversing southern Ontario
Thursday AM that then heads into Upstate NY Thursday evening. The
mean 250-500mb mean trough axis is also becoming increasingly more
positive, which is resulting in less deepening of the developing
over Upstate NY by Thursday morning. With these trends, the best
divergence and moisture aloft will reside to the north of the 500mb
low over western and far northern NY. Guidance still disagrees as
to the duration and intensity of the snowfall, but the setup still
favors the development of a TROWAL over the region. Snow will
envelop the Adirondacks and North Country that could reach as far
south as the Finger Lakes. Snow is expected across much of northern
New England Thursday morning, but it is worth noting there is
evidence of a 700-300mb dry slot quickly advancing in from the
southwest that could try to end snowfall sooner over the
Adirondacks, Hudson and Champlain Valleys, and into the Green and
White Mountains. The one area that could still see wrap around
snow is western NY and the Chautauqua Ridge where the pivoting
TROWAL and lake enhanced snow bands are likely to linger through
the remainder of Thursday. Snow is also expected to the north of
the 500mb vort max over northern Maine before tapering off Friday
morning.

WPC 24-hour probabilities show the NY's shores along Lake Ontario
and NY's North Country as having moderate chances (40-60%) for
snowfall totals >6" through Thursday night with the Tug Hill
Plateau sporting low chances (10-30%) for localized snowfall totals
approaching a foot. The peaks of the Green and White Mountains are
also likely to see over 6" of snow while northern Maine shows low-
to-moderate chances (30-50%) for snowfall totals >4".

Farther south, guidance has also gradually trended less snowy in
the central and southern Appalachians. Persistent upslope low
amidst cyclonic flow that taps into Great Lakes moisture is likely
to produce anywhere from 1-4" of snow from the Laurel Highlands on
south through the Potomac Highlands and into the Blue Ridge and
Smokey Mountains of TN/NC. The >3,000ft mountain ranges in eastern
WV and the peaks of the Smokeys shows moderate chances (40-60%) for
localized snowfall totals >4" through Thursday afternoon. Snowfall
will taper off by Thursday evening as high pressure over the South
builds in over the region Thursday night.


...Upper Midwest & Northern Plains...
Day 3...

On Thursday, another Canadian clipper system ushers in another
round of snow over northern MN, northern WI, and the western U.P..
A plume of moisture associated with a ribbon of 850-700mb FGEN will
produce some minor snowfall accumulations Thursday afternoon. As
the snow via WAA moves into the U.P. Thursday night, another arctic
front will race south through the Northern Plains. The strong CAA
and steepening lapse rates may trigger snow squalls over the
Dakotas and as far west as eastern MT. WPC probabilities
favor northern MN and northwest WI for low-to-moderate chances
(30-50%) for snowfall totals >4", although a coating to 1" due to
passing snow squalls in the Northern Plains are also possible,
along with strong wind gusts that could result in whiteout
conditions locally Thursday night and early Friday morning.


Mullinax




$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 132020
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
320 PM EST Tue Jan 13 2026

Valid 00Z Wed Jan 14 2026 - 00Z Sat Jan 17 2026


...Northern Plains through the Northeast, and the Appalachians...
Days 1-3...

A trough across the eastern CONUS will amplify impressively and
periodically re-load through the period as repeated shortwaves
intensify and drop southeast from Canada. The core of this trough
will deepen most impressively to reach the Gulf Coast Thursday aftn
(NAEFS 500mb heights below the 1st percentile within the CFSR
climatology), but remain below the 10th percentile with secondary
amplification occurring on Friday.

Within this trough, and really the driving factor behind amplifying
this trough, will be repeating shortwaves digging out of Canada and
racing southeast through the flow. The first of these will move
from Minnesota to the Ohio Valley D1, with a secondary piece
approaching the Gulf Coast, with both of these impulses rotating
eastward during D2, producing the most intense troughing on
Thursday. Within this progressive flow, even as these lead impulses
rotate away on Friday, the next vorticity lobe will follow
immediately in its wake, moving from the Northern Plains to the
Mid-Mississippi Valley on D3.

This pattern will produce multiple days of lake effect snow (LES)
downwind of the Great Lakes, especially in the more northerly belts
as winds become NNW beneath strong CAA. 3-day WPC probabilities for
LES are high (>70%) for more than 8 inches in the higher elevations
of the U.P. including the Huron and Porcupine Mountains, as well as
along the E/SE shore of Lake Michigan into northern Indiana, and
across the Tug Hill Plateau, with lower but still significant
probabilities (30-50%) for 8+ inches along the Chautauqua Ridge.
The heaviest LES is likely in a single band off Lake Michigan into
SW MI/NW IN late Wednesday through late Thursday.

Across the Central Appalachians and Northeast, the lead shortwave
will not only work together with an Atlantic-offshore jet streak to
create low pressure development across the Northeast, but also drag
an arctic front from the Ohio Valley through the Mid-Atlantic on
Thursday. This will create a short period of heavy upslope snow
from the higher elevations of NC through the Laurel Highlands of PA
where WPC probabilities are moderate (50-70%) for at least 4
inches, generally above 3000 ft, with locally 6-8 inches possible.
Farther north into Upstate NY and northern New England, a weak
TROWAL may pivot westward north of the surface low and combine with
an inverted surface trough to enhance snowfall D2. Trends in the
guidance continue to shift the heaviest snowfall north into Canada,
but a narrow corridor of heavy snow is likely, reflected by WPC
probabilities for 6+ inches that are 50-70% from eastern Lake
Ontario (where some lake enhancement is likely) through the St.
Lawrence Valley and the Adirondacks.

Finally, on D3 with the next shortwave digging out of Saskatchewan
into the Upper Midwest, height falls and modest warm/moist
advection will create a swath of generally light snow, followed by
strong winds behind yet another arctic front. WPC probabilities
indicate only a 10-30% chance for at least 4 inches of snow for
parts of SD/MN/WI, but WSSI-P suggests an increasing threat for
blowing snow impacts just behind this wave, so travelers should be
prepared for hazardous driving Friday despite the modest snowfall
amounts forecast.


Weiss


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 140751
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
251 AM EST Wed Jan 14 2026

Valid 12Z Wed Jan 14 2026 - 12Z Sat Jan 17 2026


...Northern Plains through the Northeast, and the Appalachians...
Days 1-3...

A longwave trough across the eastern CONUS will amplify and
periodically re-load through the upcoming weekend as repeated
shortwaves intensify and drop southeast from Canada. The core of
this trough will deepen most impressively over the Gulf Coast
Thursday aftn (ECMWF 500mb heights as low as the 0.5 climatological percentile). Within this progressive flow, even as these lead
impulses rotate away on Friday, the next shortwave trough will
follow immediately in its wake, moving from the Northern Plains to
the Mid-Mississippi Valley Friday night. Similar to the Southeast
on Thursday afternoon, 500mb heights over the Missouri River Valley
are likely to be as low as the 0.5 climatological percentile.

The headlining weather hazard, aside from some of the coldest
temperatures and wind chills of the season-to-date, will be the
multiple days of lake effect snow (LES) downwind of the Great
Lakes, especially in the more northerly belts as winds become NNW
beneath strong CAA. WPC probabilities for LES are high (>70%) for
more than 8 inches in the higher elevations of the U.P. including
the Huron and Porcupine Mountains, as well as along the E/SE shore
of Lake Michigan into northern Indiana. Lake-enhanced snowfall
will also unfold along the Chautauqua Ridge and Tug Hill through
Thursday. There are likely to be some localized totals over 12
inches along the Chautauqua Ridge, along the shores of Lake
Ontario, and on the Tug Hill. The heaviest LES is likely in a
single band off Lake Michigan into SW MI/NW IN late Wednesday
through late Thursday. CAMs guidance is showing steep lapse rates
and exceptional vertical velocities that coincide within a fully
saturated DGZ-- a clear sign of a robust LES band. WPC
probabilities show moderate chances (40-60%) for snowfall totals

12 inches where localized amounts approaching 20" cannot be ruled

out given the potential for prolific >2"/hr snowfall rates beneath
a band that will oscillate between southwest MI and northwest IN
for a 12-24 hour stretch.

Across the Central Appalachians and Northeast, the lead shortwave
will not only work together with an Atlantic-offshore jet streak to
create low pressure development across the Northeast, but also drag
an arctic front from the Ohio Valley through the Mid-Atlantic on
Thursday. This will create a short period of heavy upslope snow
from the higher elevations of NC through the Laurel Highlands of PA
where WPC probabilities are moderate (50-70%) for at least 4
inches, generally above 3000 ft, with locally 6-8 inches possible.
The tallest peaks of the Smokey Mountains could see localized
totals approach 12 inches. Farther north into Upstate NY and
northern New England, model guidance has trended snowier over the
past 12-24 hours of model cycles as the slightly longer duration
of moderate-to-heavy snowfall just north and west of the 850mb low
appears to be coming to fruition. The deformation zone will
maintain a saturated profile long enough, within an atmosphere that
supports rising SLRs, to produce heavy snowfall beginning as early
as Wednesday afternoon and continuing into Thursday. WPC
probabilities show moderate-to-high chances (50-70%) for snowfall
totals >8 inches from northwest PA through much of western NY and
into NY's North Country and St. Lawrence Valley.

Finally, on D3 with the next shortwave digging out of Saskatchewan
into the Upper Midwest, height falls and modest warm/moist
advection will create a swath of generally light snow, followed by
strong winds behind yet another arctic front. WPC probabilities
indicate only a 10-30% chance for at least 4 inches of snow for
parts of SD/MN/WI, but WSSI-P suggests an increasing threat for
blowing snow impacts just behind this wave, so travelers should be
prepared for hazardous driving Friday despite the modest snowfall
amounts forecast. Farther east, the shortwave trough will once
again kick-up LES bands across the U.P. and western shores of
Michigan. WPC probabilities show high chances (>70%) for snowfall
totals >4 inches in the U.P.'s Porcupine Mountains and moderate
chances (40-60%) for >4 inches of snow over the western MI shore.
The Porcupines have the best odds at locally heavy totals with
low-to-moderate chances of totals >8 inches.


The probability for significant ice across the CONUS is less than
10%.


Mullinax/Weiss





$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 141935
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
235 PM EST Wed Jan 14 2026

Valid 00Z Thu Jan 15 2026 - 00Z Sun Jan 18 2026


...Upper Midwest through Northeast, and the Appalachians...
Days 1-3...

The longwave trough in place across the eastern CONUS will
repeatedly reload into the weekend, becoming increasingly amplified
as shortwaves periodically drop south out of Canada and rotate
through the trough and then off the east coast. The core of this
trough will deepen most impressively over the Gulf Coast Thursday
aftn (ECMWF 500mb heights as low as the 0.5 climatological
percentile). Within this progressive flow, even as these lead
impulses rotate away on Friday, the next shortwave trough will
follow immediately in its wake, moving from the Northern Plains to
the Mid-Mississippi Valley Friday night. Similar to the Southeast
on Thursday afternoon, 500mb heights over the Missouri River Valley
are likely to be as low as the 0.5 climatological percentile.

In addition to producing true winter cold air across much of the
eastern 1/3 of the CONUS, and potentially some of the coldest wind
chills of the season, widespread snow is likely from the Upper
Midwest through the Tennessee Valley and back northeast through the
Central Appalachians and into the Northeast. While most of this
snow will be more "conversational" and light than impactful, there
are a few areas that will experience more significant snowfall.

Great Lakes: Periods of lake effect snow (LES) are likely each day
as persistent cyclonic flow and periodic shortwaves/fronts renew
CAA across the lakes. The heaviest LES is likely D1, especially
downwind of Lake Michigan into northern Indiana where, despite some
modest longitudinal fluctuations in the axis from the most recent
model runs, a long fetch north-south across Lake Michigan should
result in a narrow and intense single band of snow into far SW MI
and northern IN. Here, HREF probabilities for 1+"/hr snowfall peaks
above 60% for much of D1, and with locally 2-3"/hr snowfall rates
possible, WPC probabilities support a high risk (>70%) for more
than 12", and locally up to 20 inches is possible. Elsewhere, heavy
snowfall is likely south of Lake Erie along the Chautauqua Ridge
where WPC probabilities indicate a moderate risk (30-50%) for more
than 12 inches. Otherwise, while LES will be periodic and briefly
intense at times all 3 days, additional snowfall in other areas
should generally be around 6 inches or less, especially southeast
of Lake Ontario and across portions of the U.P. of MI.

Central Appalachians: The passage of an arctic front associated
with the lead shortwave will quickly cool the column to change
precipitation from rain to snow, with post-frontal gusty westerly
winds leading to pronounced upslope flow. Regional soundings
suggest favorable ascent into steepening lapse rates and elevated
low-level moisture to support heavy snow rates from the higher
elevations of NC near the Smoky Mountains northward through the
Central Appalachians of WV and into the Laurel Highlands. Guidance
has trended a little wetter and more intense with this event, and
WPC probabilities now reflect a high chance (>70%) for more than 6
inches in the higher terrain, generally above 3000 ft, across this
region on D1. Light snow showers will likely continue, although
with minimal additional accumulations on D2, but renewed upslope
flow with a secondary front D3 could again result in a few inches
of snow (WPC probabilities above 30% for 4+ inches) across the
higher elevations from NC to WV once again.

Interior Northeast: A surface low pressure moving across PA tonight
will continue to push northeast, reaching Atlantic Canada by
Friday morning. This low will be accompanied by modest warm/moist
advection to spread precipitation across Upstate New York and
northern New England. While the guidance has trended north to focus
the heaviest snowfall across Canada, a modest TROWAL pivoting
westward behind this low and interacting with an inverted surface
trough elongated from the primary low will pivot some heavier
snowfall tonight through Thursday aftn. Brief snowfall rates in
excess of 1"/hr are possible (10-30%) across the Adirondacks,
northern VT, and near Lake Ontario tonight before lifting northeast
through Thursday. As the low pulls away, some upslope snow on
increasing NW winds may also lead to heavier rates across the
Adirondacks and Greens. WPC probabilities across this area are
moderate (30-70%) for 8+ inches of snow through Friday, with the
greatest accumulations likely near the St. Lawrence Valley, the
Adirondacks, and the northern Greens.


...Northern/Central Plains...
Day 2...

A potent shortwave and accompanying vorticity lobe will drop
rapidly southward out of Saskatchewan/Manitoba into the Dakotas and
then continue to dig southeast reaching the Mid-Mississippi Valley
by 00Z Saturday /end of D2/. This feature will drive an arctic cold
front southward, and the overlap of modest, but transient, height
falls, PVA, and low-level convergence along the front will
manifest as periods of snow showers, with coverage and snowfall
amounts limited by below-normal PWs and ongoing CAA. However,
impressively strong winds within the PBL and exceptionally steep
low-level lapse rates will encourage any snow showers to be
accompanied by gusty winds, and where low-level fgen combines with
modest 0-2km CAPE of 100-200 J/kg, convective snow showers may
result. While the duration and coverage of these may be limited, as
reflected by most simulated reflectivity, any of these snow
showers will likely include limited visibility and brief heavy snow
rates. This could produce hazardous travel as reflected by 30-50%
chance for moderate impacts from the WSSI-P despite snowfall
amounts that will likely (>70% chance) be less than 2 inches from
the Dakotas into western Minnesota and down into Nebraska/Iowa.


The probability for significant ice across the CONUS is less than
10%.


Weiss


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 150823
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
323 AM EST Thu Jan 15 2026

Valid 12Z Thu Jan 15 2026 - 12Z Sun Jan 18 2026


...Northeast...
Day 1...

Accumulating snowfall will be ongoing this morning across western
and northern NY into northern New England. Additional accumulations
after 12z will be highest across western NY (where some lake
enhancement will occur) and over northern ME...with the probability
of 4"+ of additional snow over 70%. This area of snow will wind
down tonight, although some lingering lake effect snow will
continue along with some wrap around snow into northern ME.


...Central and Northern Plains into the Great Lakes...
Days 1-3...

A mid level trough with multiple lobes of embedded vorticity will
drop into the Northern Plains and Great lakes today into Friday
bringing periods of snow. One area of snow will move into MN, WI
and the Great Lakes ahead of and associated with a low moving out
of Canada today into Saturday. Mainly looking at light snowfall
accumulations with this low, although some heavier totals can be
expected off of Lake Superior and Lake Michigan. Overall this is
setting up to be a long duration of light to moderate snowfall
across these lake effect areas, with 72hr probabilities of
exceeding 8" of snow in the 70-90% range across portions of the
western U.P of MI into northeast WI...and 50-70% over western MI.
Lighter amounts, generally in the 1-4" range, can be expected over
MN into WI.

Snow showers will also accompany this system farther west across
the Dakotas into NE, both along the southward dropping cold front
and in its wake. Snowfall amounts are not expected to be
significant, generally on the order of 1-2" or less...however this
snow will be accompanied by significant wind gusts, likely
resulting in reduced visibility and hazardous travel. These snow
showers should start in ND by Thursday evening, spreading south
into SD Thursday night, and then continuing over much of the
Northern Plains through the day Friday. HREF EAS probabilities of
.01" can be a decent proxy for snow shower coverage...and these
values increase into the 70-100% range Thursday night over much of
ND into eastern SD, dropping closer to 40-60% during the day
Friday. Thus anticipating numerous to widespread coverage of snow
showers as the cold front pushes across Thursday night, decreasing
to scattered coverage during the day Friday. Heavier snow shower
coverage may be more isolated to scattered in nature...but where
these brief heavier rates occur a sharp reduction in visibility can
be expected with wind gusts as high as 40-60 MPH. This setup would
seemingly support at least some snow squall potential near and
just behind the cold front as it drops south Thursday night. Snow
shower coverage and intensity should generally be on a downward
trend Friday, however wind gusts will remain high. One limiting
factor for blowing snow impacts from this system is the lack of
antecedent snow cover...however if we are able to get snowfall
accumulations ~2" Thursday night into early Friday then blowing
snow concerns could increase during the day Friday, especially
within snow showers.


...Ohio Valley, Southeast, Mid-Atlantic and Northeast...
Days 2-3

A decent amount of uncertainty exists Friday night into Sunday from
the OH Valley into the East Coast...all related to how the multiple
vort maxes interact within the large scale trough moving towards
the East Coast. Model guidance is trending a bit stronger with one
lobe of vorticity Friday night into Saturday moving from the OH
valley into the Mid-Atlantic. This should support an expanding area
of light to moderate precipitation across TN/KY Friday night,
spreading into the Mid-Atlantic and Northeast on Saturday. Not
anticipating any significant snowfall from this feature, but some
light snow accumulations are possible over portions of northeast TN
into KY Friday night. Temperatures are marginal, but enough of the
guidance is just cold enough to support the potential for 1-2" of snowfall...and the latest WPC probabilities of 1"+ are in the
30-60% range, which seem reasonable. Some light snow (generally
under 1") could then spread into portions of the northern Mid-
Atlantic saturday morning, with totals upwards of 1-3" possible
across the interior Northeast.

Attention will then turn to energy diving into the base of the
large scale trough and how this evolves from the Gulf Coast to the
East Coast. Seemingly have 3 deterministic model camps with this
system. The 00z GFS is the slowest and most aggressive with this
feature, taking it neutral to negatively tilted by 12z Sunday
resulting in a more expansive swath of precipitation over the
Southeast Saturday night into Sunday morning. While boundary layer
temperatures are marginal, some accumulating snowfall would be
possible over the Southeast states in this scenario. On the other
hand the ECMWF, while slower like the GFS, is more positively
tilted, keeping the system more suppressed, and thus little to no
winter precip through 12z Sunday. The 00z AIGFS/AIFS/GEM all depict
a quicker shortwave trough that results in a precipitation axis
farther east than the GFS, but moving quicker up the East Coast as
well. This scenario is a warmer one however, with the bulk of the
precipitation staying ahead of the colder airmass. Thus most of the
precip over the Southeast in this scenario is rain through 12z
Sunday. Not really seeing any clear trend to support hedging one
way or another with the forecast at this point, so will just need
to continue to monitor and hope for a more consistent trend today.
Current probabilities of 1"+ of snow through 12z Sunday are low,
only peaking around 5-10% over portions of AL and GA. Probabilities
do increase into the 20-30% range from NC into New England later
Sunday, but the aforementioned model spread will play a significant
role in how that forecast plays out.

Chenard



$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 152046
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
346 PM EST Thu Jan 15 2026

Valid 00Z Fri Jan 16 2026 - 00Z Mon Jan 19 2026

...Central and Northern Plains into the Great Lakes...
Days 1-3...

Persistent longwave trough across the eastern CONUS will=20
repeatedly re-load through the weekend in response to multiple=20
embedded shortwave troughs and accompanying vorticity lobes=20
swinging through.=20

The first of these will be exiting the Northeast into
Atlantic Canada D1 as a closed low with the accompanying trough
axis extending into the Southeast. Behind this trough and the
accompanying cold front, strong CAA in its wake will drive
continued lake effect snow (LES), especially east of Lakes Erie=20
and Ontario before shortwave ridging develops Friday aftn shutting
off the LES. WPC probabilities D1 are modest for 4+ inches of
additional snow, highest southeast of Lake Ontario where it reaches
30-50%.

Immediately in the wake of this first impulse, a second shortwave
will dig out of Saskatchewan and race S/SE, reaching the Mid-
Mississippi Valley by D2 before continuing to rotate E/NE into New
England on Sunday. This shortwave will push a power arctic cold
front southward beneath it, and a clipper-type low is also expected
to track to the southeast across the Great Lakes during this time.
While the accompanying synoptic snow through WAA is likely to be
minimal, renewed CAA across the Lakes should result in additional
LES, with more widespread coverage as cold N/NW flow envelops the
entire region. A third shortwave is expected to cross into the
Great Lakes on Sunday with subsequent ascent and moisture leading=20
to more snowfall, but additional accumulations before 00Z Monday
should be minor. Before that time, however, 3-day snowfall
probabilities from WPC indicate a high risk (>70% chance) for at=20
least 8 inches across the western U.P. and much of the western=20
shore of the L.P. where locally 1-2 feet is possible. Lesser=20
amounts are expected east of Lake Ontario, but still modest=20
accumulations exceeding 8 inches have a low chance (10-30%) of=20
occurring.

In addition to the LES, the arctic cold front and post-frontal CAA
will provide sufficient ascent for widespread snow showers and
possible snow squalls across the Northern Plains, Upper Midwest,
and potentially into parts of the Great Lakes/Ohio Valley. This
will begin tonight across the Dakotas, and then persist through
Friday night while expanding southeast. While the setup does not
appear extremely favorable for strong snow squalls, linear bands
aligned perpendicular to the front within a region of elevated
0-2km fgen, increasing low-level moisture, and steepening lapse
rates where winds at the top of the PBL exceed 50 kts in some
areas, will support widespread snow showers (or squalls) with brief
heavy snow rates and gusty winds. While snowfall accumulations
across this region accompanying these squalls will be minimal, when
snow occurs it will fall heavily, and when combined with the strong
winds will create periodic near zero visibility and dangerous
driving. The alignment of these snow showers/squalls will also
support multiple rounds in some areas through D2.

Key Messages have been issued for these snow squalls, and they are
linked at the bottom of this discussion.


...Ohio Valley, Mid-Atlantic, and Northeast...=20
Days 1-3...

Progressive flow within a reloading and persistent mid-level
longwave trough will create active winter weather across the area
through the weekend.

For D1, a low pressure system rapidly exiting into Atlantic Canada
will leave residual moisture and ascent across primarily Maine
where a theta-e ridge continues to pivot briefly tonight, with
increasing NW flow/upslope ascent occurring as the low pulls away.
Forecast soundings indicate a rapid drying of the DGZ tonight so
any moderate snow should wane quickly by Friday morning, but WPC
probabilities indicate a low risk (10-30%) for an additional 4+
inches of snow in northern ME.

Thereafter, the mid-level trough begins to re-amplify in response
to a shortwave diving through the Great Lakes and elongating into
the Ohio Valley and Central Plains. This evolution will drive an
arctic cold front sharply east, reaching the Mid-Atlantic states by
the end of D2 /00Z Sunday/. A shortwave downstream of this front
may help develop a wave of low pressure which will bring some light
to moderate snowfall to New England, although WPC probabilities for
more than 2" of snow D2 are only around 30%, highest in the higher
elevations of the Catskills and Berkshires. More substantial
snowfall is likely through lift along the front, followed by
impressive upslope snow into the Central Appalachians, as well as
parts of western PA. Steepening lapse rates will keep the DGZ
relatively shallow, but sufficient ascent into the moistened column
will result in periods of moderate to heavy snowfall which may
accumulate to more than 4 inches in parts of WV and PA as reflected
by WPC probabilities reaching 30-50%.

Then during D3 /00Z Sunday to 00Z Monday/ an elongated lobe of
vorticity will swing into New England, while a secondary and
sharpening shortwave dives into the primary longwave trough across
the Mississippi Valley. While the lead impulse may cause some light
snow across Maine (WPC probabilities for 4+ inches 10-30%), the
more challenging and bigger concern will be what happens with
moisture spreading northward from the Southeast the latter half of
D3. While uncertainty is significant, there is at least modest
confidence that light precipitation will spread far enough
northwest to bring snowfall to parts of the Mid-Atlantic coast from
eastern VA through coastal NJ, and potentially onto Long Island and
Cape Cod. Current WPC probabilities are modest (30-50% for 1"), but
trends will need to be monitored as the system develops in the next
few days.


...Southeast...
Day 3...

A complex forecast scenario is evolving for portions of the
Southeast beginning around 00Z Sunday and persisting through D3. An
arctic cold front will push into the area Saturday and then=20
progress rapidly to the Atlantic Coast by Sunday morning. As this
front pushes east, a sharpening upper shortwave trough will rotate
near the Gulf Coast, potentially taking on a negative tilt late in
the forecast period (although there is a lot of uncertainty into
the amplitude of this feature). At the same time, a downstream jet
streak will amplify to become powerful over the Mid-Atlantic and
Northeast, leading to weak surface cyclogenesis along the Gulf
Coast. As this wave develops, moisture will spread northward, and
while the column will initially be too warm for wintry
precipitation, rapid cooling behind the front will allow for a
changeover from rain to snow.=20

The speed at which this occurs, as well as how much moisture can=20
remain in the column after transition, will play the most important
role into any possible snowfall accumulations. The GFS continues=20
to be the most robust with the transition and available moisture=20
for snow, while the EC and CMC are weaker and drier. Evaluation of=20
the D3 clusters suggests that both the CMC and GFS ensembles are=20 under-dispersive (with the CMC members nearly uniformly deeper=20
with the trough, while the GFS members are nearly uniformly faster=20
at 500mb), suggesting the EC members and their variety of=20
solutions results in a more accurate solutions via the ECENS mean.
While there is still a lot of uncertainty, confidence is increasing
for at least mixed rain/snow from the Florida Panhandle northeast
through southeast Virginia. While the threat for significant
accumulations appears small, and WSE plumes only have a handful of
members producing >1" of snow, the WPC probabilities have increased
and suggest a 10-30% chance for 1" of snow from southern AL through
the NC Piedmont and into the coastal Mid-Atlantic states. Forecast
changes are almost certain, so those potentially impacted should
remain apprised of the latest forecast through the next few days.


Weiss


...Winter Storm Key Messages are in effect. Please see current=20
Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!6RNjUAou4g17Px_u1pNFlRzORKhcuzmoTm4odAbI2R7Ol= g8xKox0NZQc9EVJ7SQwiAS7NX09bAHxt-zgZW50whtt9wE$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 160911
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
411 AM EST Fri Jan 16 2026

Valid 12Z Fri Jan 16 2026 - 12Z Mon Jan 19 2026

...Central and Northern Plains into the Midwest...=20
Days 1 and 3...

Longwave trough re-establishes over the Great Lakes today where it
persists into next week as multiple shortwave troughs swing
through.

An arctic cold front currently pushing across ND will push
south-southeast into the Midwest today. Strong frontal CAA will=20
continue to provide sufficient ascent for widespread snow showers=20
and likely additional snow squalls both along the front as it=20
moves across the rest of the north-central Plains through the
Missouri River Valley today and potentially IL/IN this evening.=20
Potent snow streamers in cloud streets/horizontal convective rolls=20
in the NW flow behind the front should also trigger snow squall
warnings particularly over SD/Neb this morning through midday.=20=20
Some particulars on the linear bands include alignment=20
parallel to the flow within a region of elevated 0-2km fgen,=20
increasing low- level moisture, and steepening lapse rates where=20
winds at the top of the PBL exceed 50 kt. Snowfall in these
potentially lingering/repeating banding could become locally heavy=20
and when combined with the strong winds will create near zero=20
visibility and dangerous driving.=20

Key Messages are being updated for these snow squalls with the link=20
at the bottom of this discussion.


...Great Lakes...
Days 1-3...

The potent wave with the Arctic front has a leading cold front
currently over IA/KS which will swing east to the Appalachians
tonight and off the Eastern Seaboard Saturday with the Arctic
front quickly on its heels. The next reinforcing shortwave trough
then crosses the Great Lakes Sunday/Sunday night.=20
Renewed CAA across the Great Lakes today will reinstate LES with=20
more widespread coverage in snow belts as cold N/NW flow envelops=20
the entire region. Day 1 PWPF for >6" is 30-50% over the western
U.P., and the western L.P. This shifts to the Tug Hill and across
southern VT/NH for Day 1.5. Then Days 2 and 3 are highlighting
again over the western U.P. and western L.P.


...Ohio Valley, Appalachians, and Northeastern Seaboard... Days=20
1-3...

Progressive flow within a reloading and persistent mid-level
longwave trough will create active winter weather across the area
through the weekend.

The arctic cold front reaches the Ohio Valley late tonight and the
Mid- Atlantic states Saturday. Snowfall is likely through lift=20
along the front, followed by impressive upslope snow for the=20
Central and Southern Appalachians. Steepening lapse rates will=20
keep the DGZ relatively shallow, but sufficient ascent into the=20
moistened column will result in periods of moderate to heavy=20
snowfall with Day 1.5 PWPF for >4" spotty for 20-40% probs from
western PA through WV and the higher Apps along the TN/NC border.

Sunday and Sunday night an elongated lobe of vorticity will swing=20
into New England, while a secondary and sharpening shortwave dives=20
into the primary longwave trough across the Mississippi Valley.=20
While the lead impulse should bring snow to northern Maine (WPC Day
2 probabilities for 4+ inches 10-30%), the more challenging and=20
bigger concern will be what happens with moisture spreading=20
northward from the Southeast and along the Mid-Atlantic Coast=20
starting late Saturday night. Confidence is growing for light to
moderate snow from eastern VA through coastal NJ, Long Island, and
southern New England where Day 2.5 probs for >2" are 20-80%=20
(highest in on the central Jersey Shore. The low track is offshore,
so this is the backside precip.


...Southeast...
Days 2/3...

A baroclinic leaf develops downstream of the digging, positively
tilted trough axis over the Mid-South Saturday night with strong
cold air advection and snow potential for the Southeast
Piedmont through the shortwave trough passage Sunday evening. This
is the southern extent of the more notable snow mentioned above for
the Mid-Atlantic. Day 2.5 snow probs for >1" are around 40% in
Southeast VA with some 20% reaching into central NC. While most
guidance has low to no snow, there are notable outliers like the
06Z NAM with decent snow from central GA through central NC. This
will continue to be monitored as the system gets into the CAMs
today.


Jackson



...Winter Storm Key Messages are in effect and linked below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!5nz7zLo_-HKjp4ztUZSBDzH0Pt66De4raR4tqx5cnhKfQ= 4qGdTeZ-Djv7G_j9Nm6i4uqmWZChgeiXy02GdB7imda5mE$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 161925
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
225 PM EST Fri Jan 16 2026

Valid 00Z Sat Jan 17 2026 - 00Z Tue Jan 20 2026

...Central and Northern Plains into the Midwest...=20
Days 1 and 3...

With a longwave trough and embedded shortwaves forecast to persist
the next few days, bouts of snow will continue for the Plains to
the Great Lakes/Midwest. Snow squalls along the Arctic front will
yield generally low amounts of snow but potentially
hazardous/dangerous driving conditions. Snow showers and squalls=20
this afternoon will shift southward/eastward tonight through the
Midwest with less coverage. Another shortwave from Canada will
carry another threat for some banded snow showers and some snow=20
squalls Sunday over the Northern Plains to the Upper Midwest/Corn=20
Belt. Snowfall in these potentially lingering/repeating banding=20
could become locally heavy for a time and when combined with the=20
strong winds will create near-zero visibility.=20

Key Messages for these snow squalls are linked at the bottom of=20
this discussion.


...Great Lakes...
Days 1-3...

Persistent cyclonic flow around the Great Lakes will favor rounds=20
of lake effect snow downwind of all Great Lakes Lead system tonight
will favor Michigan (esp. the U.P.) as the surface low moves into=20
Ontario. Next system on Sunday will renew the lake machine across=20
Michigan then into the NY lake belts as the next area of low=20
pressure moves right across Lake Superior into Ontario. WSW flow=20
over Lakes Erie/Ontario could move the bands quite far north (e.g.,
north of BUF and ART) but the progressive flow would vary the band
locations through the period. Three-day snow totals will be=20
modest, with the favored areas (northern shore of the U.P., western
Lower Michigan, and into the Tug Hill) show >50% probabilities for
at least 12 inches of snow.=20


...Ohio Valley, Appalachians, and the Northeast...
Day 1...

Shortwave and cold front out of the Midwest will move into the
Appalachians with generally light to locally modest snow, enhanced=20
over the terrain (western PA/MD and eastern WV) tonight. WPC
probabilities for at least 4 inches of snow are about 20-50%.=20

A strengthening upper jet will move into the Northeast early
Saturday with modest snowfall expanding through the interior
Northeast, especially over the Berkshires and into the southern
Green Mountains just ahead of the cold front. Snow could exceed
1"/hr in areas of the Poconos and northwestern NJ through parts of
the Catskills and into western MA per the 12Z HREF (30-60%=20
chance). The front should clear eastern Maine after 00Z and largely
end most accumulation. WPC probabilities for at least 6 inches of=20
snow are >50% over northwestern MA into southern VT as well as into
the Tug Hill Plateau.


...Southeast, Mid-Atlantic, Northeast...
Days 2-3...

Within the active pattern in the East is a southern portion of the full-latitude trough that swings through the Lower MS Valley=20
Sunday morning. This will bring colder temperatures to the
Southeast as precipitation is slowly moving through the region
along/behind the front. Models have been struggling with how
quickly to move in colder air as precipitation ends, but some light
snow is possible over GA into the Carolinas Sunday morning of a
dusting to a tenth or two.=20

Further up the coast, precipitation will expand northeastward in
the right rear quad of the >160kt jet atop marginal to cold
temperatures (milder along/east of I-95 in the Mid-
Atlantic). Elongated baroclinic zone and areas of surface low=20
pressure will lift northeastward just off the Mid-
Atlantic/Northeast coast Sunday night. Models have struggled here
with the westward QPF extent and are sensitive to the
timing/strength of upstream/incoming mid-level systems as the flow
remains wide open. For now, have remained fairly steady on the
amounts which should result in a swath of a few inches of snow from
the Mid-Atlantic into the NYC area and New England. Highest
probabilities for at least 4 inches of snow are in eastern Maine

50%) as any chance of a more organized system is higher as it=20

approaches Nova Scotia. However, a light snow of 1-3" is likely=20
from NJ northeastward along/east of I-95/91 where WPC probabilities
of at least 2 inches are at least 30%.

Fracasso


...Winter Storm Key Messages are in effect. Please see current=20
Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!87Gc6PAfEmAFY1wwwek2esPmSCIZYqVDtFagoGIre7OrO= jq5eIs55aadK1HxyPINNkLRan8wbhzLqIvIYfPQxq8pr0A$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 170856
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
356 AM EST Sat Jan 17 2026

Valid 12Z Sat Jan 17 2026 - 12Z Tue Jan 20 2026


...Great Lakes...
Days 1-3...

Shortwave trough passages in persistent cyclonic flow through the=20
Great Lakes will favor rounds of lake effect snow for at least the
next week.

A long wave trough over the western Lakes this morning will slowly
shift east through tonight. Northerly flow over Lake Superior will
bring LES to the western U.P. with westerly flow over the L.P.
where Day 1 snow probs for >6" are 40-60% in narrow snow belts.

The next reinforcing trough moves in from the west with NWly flow
bringing more snow to the western U.P. and most of the L.P. western
shore. SWly flow over Lake Erie pushes some single banding into
Buffalo, NY. These areas have Day 2 snow probs for >6" in the
20-60% range. Then the next shortwave trough moves in from the west=20
Monday night with LES until ridging builds briefly late Tuesday.
Day 3 PWPF for >6" is over the eastern U.P. on westerly flow along
with the northern L.P. Most notably however, is single banding in
westerly flow over Lakes Erie and Ontario with Day 3 PWPF for >6"
40-80%.


...Ohio Valley, Appalachians, and the Northeast...
Day 1...

Arctic cold front will shift east from the Midwest this morning and
cross PA this afternoon. Snow squalls could accompany this front
mainly over Ohio and western PA/NY which are highlighted in ongoing
Key Messages that are linked below.=20

A SWly jet stream strengthens in place over the eastern U.S.
through tonight as a very positively-tilted trough shifts down the
Plains and pivots over the Mid-South. Downstream of this trough
will be expanding snow through the interior Northeast, especially=20
over the Poconos, Catskills, Berkshires and southern Green=20
Mountains just ahead of the cold front. Snow could exceed 1"/hr in
these areas per the 00Z HREF. This precip clears eastern Maine=20
this evening. Day 1 WPC probabilities for >4" are 50% in the Mohawk
Valley of NY and over the southern Greens, Whites, and eastern
Maine with 20-30% probs over the Poconos/Catskills, and Berkshires.=20


...Southeast, Mid-Atlantic, Northeast...
Days 2-3...

Within the active pattern in the East is a southern portion of the full-latitude trough that swings through the Lower MS Valley=20
early Sunday. This will bring colder temperatures to the Southeast
as precipitation is slowly moving through the region along/behind=20
the front. Models are in better agreement tonight allowing enough
cold air in before precipitation ends to allow some light snow from
northern FL through the Carolinas Sunday morning with a dusting to
half an inch.=20

Further up the coast, precipitation will expand northeastward in
the right entrance of the >160kt jet atop marginal to cold=20
temperatures (milder along/east of I-95 in the Mid-Atlantic).=20
Elongated baroclinic zone and areas of surface low pressure will=20
lift northeastward just off the Mid-Atlantic/Northeast coast=20
Sunday night. Models have struggled here with the westward QPF=20
extent and are sensitive to the timing/strength of=20
upstream/incoming mid-level systems as the flow remains wide open.=20
For now, have remained fairly steady on the amounts which should=20
result in a swath of a few inches of snow from the Mid-Atlantic=20
into the NYC area and New England. 10 to 20% probs for >4" in Day 2 are
limited to eastern Maine and southeastern New England. The Day 2
swath of >2" over 10% extends south through NJ into the Delmarva.


...Central High Plains...
Days 2/3...

Another Arctic cold front plunges down the Plains tonight through=20
Sunday. This banks cold air over the High Plains/against the front
ranges of the Rockies ahead of a reinforcing shortwave trough that
shifts down the Rockies Sunday night through Monday. Right entrance
jet dynamics over the existing front will allow banded snow to
develop over central MT/WY Sunday night with what appears to be the
main banding early Monday from northern CO terrain through western
KS. The WNWly orientation of these bands is parallel to flow and
should allow for persistence of moderate to locally heavy narrow
bands of snow. As of now Day 2.5 snow probs for >2" are around 20%
along the KS/CO border, but that is likely to increase as the
system gets closer. The ECAIFS was featuring this precip two nights
ago and global physical models are finally catching up. A risk for
4" or more is possible in these persistent banding scenarios.


Jackson



...Winter Storm Key Messages remain in effect and are linked=20
below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!53LqTlmiHMfFGsvloks6bLMMHenjsnI7u8iz2V4YYXMnf= wtJNLrDQZ30xNDPeBw5guoNHsTuPVbwDfbbLJhW__x0xiw$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 172007
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
307 PM EST Sat Jan 17 2026

Valid 00Z Sun Jan 18 2026 - 00Z Wed Jan 21 2026


...Great Lakes...
Days 1-3...

Shortwave trough passages in persistent cyclonic flow through the=20
Great Lakes will favor rounds of heavy lake effect snow for at=20
least the next week. The Great Lakes are currently mostly ice free
(total ice cover estimated at 15.5% on Jan 16), with surface water
temperatures between 2-6C (warmer over southern Lake Michigan and
Lake Ontario).=20

A long wave trough over Great Lakes tonight will shift east Sunday,
but reinforced by the next trough swinging around the anchored
upper low over the Hudson Bay. For D1, the highest probabilities
(40-70%) for more than 6 inches of snowfall is across the west-
central MI L.P. along the shores of eastern Lake Michigan, where=20
westerly flow and an inverted surface trough are expected to aid in
localized heavy snowfall.

The next reinforcing trough set to bring heavy snowfall during the
D2-D3 period is forecast to move in from the west with NWly flow=20
bringing more snow to the U.P. and most of the L.P. western shore.
Gusty winds up to 40 mph are also expected across the MI U.P,=20
which could lead to additional impacts associated with blowing=20
snow. SWly flow over Lake Erie pushes some single banding into=20
Buffalo, NY on Monday. These areas have Day 2 snow probs for >6"=20
in the 50-80% range. Then the next shortwave trough moves in from=20
the west Monday night with LES until ridging builds briefly late=20
Tuesday into the western Great Lakes. Day 3 PWPF for >6" is over=20
the eastern U.P. Most notably however, is single banding in=20
westerly flow over Lakes Erie and Ontario with Day 3 PWPF for >6"=20
60-90%. For the entire D1-D3 period, probabilities for >12" are
70-90% downwind of Lake Erie and Ontario, including the Buffalo
metro region.


...Southeast, Mid-Atlantic, Northeast...
Days 1-2...

Positively-tilted full-latitude trough this evening will move into
the Mid-South overnight, carrying a surface cold front through the
Southeast. By 12Z Sunday, cold front will be well into the Atlantic
with lagging precipitation over central/southeastern GA just in
advance of the sharp mid-level shortwave. With these cases, even
with surface temperatures just above freezing, dynamic cooling
could easily bring snow to the surface and accumulate via modest
rates 0.5-0.75"/hr per some of the CAM guidance. Though they have
wavered on how things come together, 12z guidance has nudged up
toward supporting a burst of snow over central/southeastern GA
which could accumulate to an inch or so (WPC probabilities of >1"
are around 10% but with upside potential). Light snow from a
dusting to half an inch is possible from the northern FL Panhandle
into upstate SC (>20-30% chance).=20

Further up the coast, precipitation will expand northeastward in=20
the right entrance of the >160kt jet atop marginal to cold=20
temperatures (milder along/east of I-95 in the Mid-Atlantic) and
increasing lower to mid-level FGEN. Elongated baroclinic zone and=20
areas of surface low pressure Sunday morning will coalesce into a
coherent surface low that is forecast to lift northeastward just=20
off the Mid-Atlantic coast to just outside the 40/70 benchmark Sunday
evening. 12Z guidance continued to trend westward with the QPF
axis/edge and have trended up in QPF and thus snow for the
Northeast. This could also keep shoreline temperatures milder for a
time before the low passes by. Snow could fall heavy for a period
over southern/southeastern New England Sunday evening per the 12Z
HREF (20-40% chance of >1"/hr rates). A swath of a few inches of=20
snow is likely from the Mid-Atlantic into the NYC area and New=20
England with upside potential over the terrain (Worcester hills,
etc.). WPC probabilities for at least 4 inches of snow are >50%
over eastern CT through RI and southeastern MA outside the Cape and
Islands. Into Maine, a stripe of a few/several inches of snow is
likely along the coast where probabilities for at least 4 inches of
snow are >40%.=20


...Northern Plains...
Day 1...

**Snow squalls likely across parts of the northern Plains on
Sunday. Key Messages linked at the bottom of the discussion***

The next in a series of arctic cold fronts is forecast to dive
southward across the northern Plains on Sunday, with the greatest
potential for scattered snow squalls along the northern High
Plains. Timing for this front and associated snow squalls/streamers
behind the front starts in eastern MT/western ND during the=20
morning hours and quickly pushes southward into western SD and NE
into the afternoon. Lapse rates per several 12z CAMs near or exceed
6-7C/km for a brief period along the front and SNSQ parameters=20
rise above 4-5 between eastern MT and central NE. These parameters=20
combined with low-to-mid level FGEN intersecting with a healthy=20
100mb wide DGZ should allow for efficient snowfall rates within=20
these showers and bands. Wind gusts up to 60 mph are also possible=20
with this system, adding to the blowing snow potential.

Snow squalls are particularly dangerous for those traveling on
roadways, with extremely low visibilities and slippery conditions
developing rapidly. Be sure to slow down, turn on your lights, and
exit the highway if possible should you get caught in a snow
squall.


...Central High Plains...
Days 2-3...

With cold air banked over the High Plains/against the front ranges
of the Rockies ahead of a reinforcing shortwave trough Sunday=20
night through Monday, conditions will be set for a period of snow
over eastern CO to KS. Right entrance jet dynamics over the=20
existing front will allow banded snow to develop over central MT/WY
Sunday night with what appears to be the main banding early Monday
from northern CO terrain through western KS. The WNWly orientation
of these bands is parallel to the flow and should allow for=20
persistence of moderate to locally heavy narrow bands of snow. As=20
of now WPC probabilities for >2" are 10-20% along the KS/CO=20
border, but that is likely to increase as the system gets closer.=20
QPF trends has been up overall and a risk for 4" or more is=20
possible in these persistent banding scenarios.

Fracasso/Snell/Jackson


...Snow Squall Key Messages are in effect. Please see current Key=20
Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_2.png__;!!DZ3fjg!4O44Oh9C5u6tIlCTliLi6mxu8BcIbKtbjpq7987JV_82b= OrTDGEDnOCpz0-LLQBikF8uV75kXdSRrKcBcTI-CQJ3RK0$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 180904
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
404 AM EST Sun Jan 18 2026

Valid 12Z Sun Jan 18 2026 - 12Z Wed Jan 21 2026


...Great Lakes...
Days 1-3...

Shortwave trough passages around an anchored deep low over Hudson
Bay maintains cyclonic flow through the Great Lakes with rounds of
heavy lake effect snow through next weekend. The Great Lakes are=20
currently mostly ice free (total ice cover estimated at 14% on Jan=20
17), with surface water temperatures between 2-6C (warmer over=20
southern Lake Michigan and Lake Ontario).

A long wave trough shifts east of the Great Lakes this morning
while the next reinforcing trough swings east across the extent of
the Lakes this afternoon through Monday. NWly flow brings Day 1=20
PWPF for >6" around 50% to the western U.P. (particularly the=20
Porcupine Mtns) and the western shore of the L.P.=20

The flow shifts westerly for Monday shifting the LES focus to the=20
eastern U.P. northern L.P. and for the eastern Great Lakes for=20
Monday with westerly single banding bringing 50-80% probs for >6"=20
to ares south of Buffalo and on the Tug Hill through Watertown.=20

A brief lull in LES sweeps across the Lakes Tuesday, though
single-banding persists on the Eastern Great Lakes. In particular,
the Tug Hill should see notable Day 3 snow with 60% probs for >12".=20


...Southeast, Mid-Atlantic, Northeast...
Day 1...

Positively-tilted full-latitude trough over the Mid-South=20
swing to neutral today as it shifts over the Southeast. Moisture
plume ahead of the trough is mainly rain, but with surface low
pressure developing off the GA coast, the back side of the precip
should turn into moderate bands of snow, particularly from the FL
Panhandle through central GA and the central Carolinas. With these
cases, even with surface temperatures just above freezing, dynamic
cooling could easily bring snow to the surface and accumulate via=20
decent rates of 0.5-0.75"/hr per the 00Z HREF. Day 1 PWPF for >2"
is around 10% in south-central GA and 20% in north-central NC into
southeast VA.

Further up the coast, precipitation will expand northeastward in=20
the right entrance of the >160kt jet atop marginal to cold=20
temperatures (milder along/east of I-95 in the Mid-Atlantic) and
increasing lower to mid-level FGEN. Elongated baroclinic zone and=20
the offshore surface low that rapidly develops as it passes Cape
Hatteras this afternoon and just outside the 40/70 benchmark=20
this evening. The westward extent of the precip shield, where the
snow bands will be is still prominent in 00Z guidance along the
extend of the Mid-Atlantic coast this afternoon and much of New
England late this afternoon through this evening. 00Z HREF mean snow
rates exceed 0.5"/hr over the Delmarva and NJ early this evening
and Long Island/southern New England late this evening through
midnight. Day 1 PWPF for >2" are 40% and up from Philly through
eastern Maine with 50% and up for >4" from NYC through CT/MA/RI and
along the immediate Maine coast. The max for the Day 1 PWPF is from
Providence to Boston where >6" probs are around 60%.=20


...Northern Plains...
Day 1...

**Snow squalls and blizzard conditions likely across parts of the=20
northern Plains today. Key Messages linked below***

The next arctic cold front surges south across the northern Plains
today, with scattered snow squalls mainly this morning from eastern
Montana through the western Dakotas into central Nebraska. The
broad wind field with this front should also trigger blowing snow,
which when combined with additional falling snow could create
blizzard conditions, particularly in the WFO FGF CWA (please see weather.gov/fgf for more info there).=20

Lapse rates reach or exceed 6-7C/km for a brief period along the=20
front and SNSQ parameters rise above 4-5 between eastern MT and=20
central NE. These parameters combined with low-to-mid level FGEN=20 intersecting with a healthy 100mb wide DGZ should allow for=20
efficient snowfall rates within these showers and bands. Wind gusts
up to 60 mph are also possible with this system, adding to the=20
blowing snow potential.

Snow squalls are particularly dangerous for those traveling on
roadways, with extremely low visibilities and slippery conditions
developing rapidly. Be sure to slow down, turn on your lights, and
exit the highway if possible should you get caught in a snow
squall.


...Central High Plains...
Days 1-2...

Cold air surges over the High Plains/against the front ranges of=20
the Rockies today ahead of a reinforcing shortwave trough that
shifts south over the Rockies tonight through Monday. Right=20
entrance jet dynamics over the front will allow banded snow to=20
develop over central MT/WY this evening with stronger banding=20
overnight from northern CO terrain through western KS with snow
bands lingering Monday morning over southwest KS into western OK.=20
The WNWly orientation of these bands is parallel to the flow and=20
should allow for persistence of narrow bands of moderate to=20
locally heavy snow. Day 1 PWPF for >2" remain limited to 30% over=20
the CO Front Range and east of the Palmer Divide in CO/western KS.
CAMs generally struggled with these synoptically driven bands that
have a risk for high performance given the motion along
orientation, so there remains a threat for 4"+ in persistent=20
banding scenarios.

Jackson



...Winter Storm Key Messages are in effect. Please see current=20
Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_2.png__;!!DZ3fjg!8mgHyoidHlr2hQD8QC6_PkFw3gcML7nZY0LgmJfp3PNA_= 50yuIFMLCOpfSkQNcKumw5V4v5BVTNpxp0ITTZIl5fYnzo$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 181903
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
203 PM EST Sun Jan 18 2026

Valid 00Z Mon Jan 19 2026 - 00Z Thu Jan 22 2026


...Great Lakes...
Days 1-3...

Shortwave trough passages around an anchored deep low over Hudson
Bay maintains cyclonic flow through the Great Lakes with rounds of
heavy lake effect snow through at least the first part of the week.
The Great Lakes are currently mostly ice free (total ice cover
estimated at 14%), with surface water temperatures between 2-6C
(warmer over southern Lake Michigan and Lake Ontario). 850mb
temperatures of -20C or so will be quite sufficient for a delta T.

The next reinforcing trough swings east across the extent of the
Lakes tonight/tomorrow along with a surface front. Post-FROPA NW
flow through early Tuesday will promote multi-banded snow into the
U.P. and western Lower Michigan where WPC probabilities for at
least 6 inches of snow through 12Z Tue are >70%. For Lakes
Erie/Ontario, SW flow ahead of the system tonight will keep the
bands mostly in Canada except for around Buffalo/Niagara Falls
before sinking back southward Monday afternoon/evening and
eventually waning on Tuesday (lastly over the Tug Hill). WPC
probabilities for at least 6 inches of snow through 00Z Wed are

90% over the Tug Hill and near/just south of Buffalo. Over the Tug

Hill where the band could persist the longest, WPC probabilities
for at least 18 inches of snow are >50%.

After a brief lull Tuesday evening in the western Lakes, another
system will move through the region overnight and into Wednesday
with the surface low lifting from the Corn Belt across Lake
Michigan through Lower Michigan. Synoptic snow will be followed by
lake effect snow on Wednesday with the highest probabilities for at
least 4 inches of snow over western Lower Michigan near the track
of the area of low pressure (>60% probs).


...Eastern New England...
Day 1...

Deepening area of low pressure just outside the 40/70 benchmark at
00Z tonight will lift quickly northeastward into Atlantic Canada
overnight. Light to modest snow and snow rates (near 1"/hr) atop
cold to marginal surface temperatures over southeastern and eastern
New England will continue snow through the early overnight hours
before winding down by 12Z Monday. WPC probabilities for an
additional 4 inches of snow after 00Z are >50% over eastern MA and
northern RI (except for the Cape and Islands) and along eastern
coastal Maine.


...Central High Plains...
Day 1...

Arctic front diving through the Plains will bring in colder air to
the High Plains tonight. Right entrance jet dynamics over the
front will allow banded snow to develop over central MT/WY this
evening with stronger banding overnight from northern CO terrain
through western KS with snow bands lingering Monday morning over
southwest KS into western OK. The WNWly orientation of these bands
is parallel to the flow and should allow for persistence of narrow
bands of moderate to locally heavy snow. Day 1 PWPF for >2" remain
limited to 30% over the CO Front Range and 10-20% east of the
Palmer Divide in CO/western KS. CAMs generally struggled with these synoptically driven bands that have a risk for high performance
given the motion along orientation, so there remains a threat for
4"+ in persistent banding scenarios (e.g., NAM nest).

Fracasso


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 190842
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
342 AM EST Mon Jan 19 2026

Valid 12Z Mon Jan 19 2026 - 12Z Thu Jan 22 2026


...Great Lakes/Upper Midwest...
Days 1-3...

Shortwave trough passages around a deep low over anchored over
Hudson Bay maintain cyclonic flow and Lake Effect Snow across the
Great Lakes snow belts at least into this weekend. The Great Lakes
are ice free away from the narrower bays. 850mb temperatures of
-20C to -25C over surface water temperatures between +2 to 6C will
continue to make for a high delta T and convective development.

A reinforcing trough currently over the U.P. swings east across
the rest of the Lakes today with a leading arctic cold front.
Post- FROPA NW flow through early Tuesday will promote multi-
banded snow into the U.P. and northern Lower Michigan where Day 1
WPC probabilities for >6" are 40-70%.

For Lakes Erie/Ontario, SWly flow veers Wly today with ongoing
single-band LES shifting south of Buffalo and onto the Tug Hill
Plateau. Day 1 PWPF for >6" are 60-80% in these zones. LES
continues through Tuesday night, so Day 2 PWPF for >6" are
especially highlighted over the Tug Hill with values over 80%.

A brief lull occurs Tuesday evening in the western Lakes under
brief ridging until the next shortwave/a clipper system shifts east
through the region Tuesday night through Wednesday. A surface low
lifts from Iowa across the L.P. through that time with synoptic
snow bands across northern Iowa and southern Wisconsin where Day
2.5 snow probs for >4" have risen to 20%. Brief LES can be expected
Wednesday into Wednesday night where Day 3 PWPF for >4" are 40-70%
in the western U.P., the length of the western L.P. shore, and east
of Lakes Erie and Ontario.

Yet another clipper is quick on the heels on a similar path to the
previous with snow bands likely over northern Iowa, southern
Wisconsin and souther Michigan again Wednesday night.


...Central High Plains...
Day 1...

Right entrance jet dynamics continue to provide lift over a
baroclinic zone on the central High Plains as high pressure builds
south over the Northern Plains. A decent swath of snow with narrow
embedded bands of moderate to locally heavy snow have developed
from northern CO Front Range to western KS. These will persist into
or through the morning as should slowly sag south to southwestern
KS as the jet also shifts south with the shortwave trough pushing
down the Rockies. An additional few inches can be expected in the
better bands.


The probability of significant icing is less than 10 percent.


Jackson




$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 192055
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
355 PM EST Mon Jan 19 2026

Valid 00Z Tue Jan 20 2026 - 00Z Fri Jan 23 2026


...Great Lakes/Upper Midwest...
Days 1-3...

A highly negative AO teleconnection will keep the large Hudson Bay
vortex in place while embedded shortwave troughs revolving around
the Hudson Bay vortex continue to trigger LES bands over the
typical snow belts. The Great Lakes are remain ice free away from
the narrower bays and coast lines. Sufficiently steep lapse rates
persist due to 850mb temperatures of -20C to -25C racing over
surface water temperatures between +2C to +6C.

For Lakes Erie/Ontario, SWly flow veers Wly today and tonight with
ongoing single-band LES shifting south of Buffalo and onto the Tug
Hill Plateau. Day 1 PWPF for >6" are 70-90% in these zones.

A brief lull occurs Tuesday evening in the western Lakes and
eventually eastern Lakes by Wednesday morning under brief ridging
until the next shortwave/a clipper system shifts east through the
region Tuesday night through Wednesday. A surface low lifts from
Iowa across the L.P. through that time with synoptic snow bands
across northern Iowa and southern Wisconsin where Day 2 snow probs
for >4" are 10-20%. Brief LES can be expected Wednesday into
Wednesday night where Day 2.5-3 PWPF for >4" are 40-70% in the
western U.P., the length of the western L.P. shore, and east of
Lakes Erie and Ontario.

Yet another clipper is quick on the heels on a similar path to the
previous with snow bands likely over northern Iowa, southern
Wisconsin and souther Michigan again Wednesday night through
Thursday. In total through Thursday, snowfall amounts are expected
to add up to at least 1 to 2 feet downwind of Lake Erie and Lake
Ontario, with higher chances (60-80%) for over 2 feet across the
Tug Hill of NY.


The probability of significant icing is less than 10 percent.


Snell/Jackson



$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 200909
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
409 AM EST Tue Jan 20 2026

Valid 12Z Tue Jan 20 2026 - 12Z Fri Jan 23 2026


...Northern Plains, Upper Midwest, Great Lakes...=20
Days 1-3...

Sprawling Hudson Bay vortex dominates the continental pattern
through this week. A pair of shortwave troughs round the low,=20
emerging from the Canadian Prairies as clippers and cross the=20
Northern Plains/Upper Midwest and the Great Lakes today and=20
Wednesday. These clippers will continue to trigger LES bands over=20
the typical snow belts in their wake.=20

The first shortwave trough axis reaches Montana this morning with
repeating areas of moderate snow through the morning with
topographical enhancements where 1"/hr snow rates are possible. Day
1 PWPF for >4" are around 50% on the Little Belt and Big Snowy
Mtns.

This clipper will redevelop snow bands over eastern SD this
afternoon with a decent, but narrow swath of snow then east along
the MN/IA and WI/IL borders tonight and southern MI late tonight
into Wednesday. Day 1.5 PWPF for >4" is 40-50% from northeast IA
along the WI/IL border and southwest MI. The Wednesday clipper
should follow a similar track, but with lower overall precip.

The Great Lakes ice coverage is rising, currently around 18%=20
mainly on narrower bays and western Lake Erie per GLERL.=20
Sufficiently steep low level lapse rates persist with 850mb=20
temperatures of -20C to -25C over surface water temperatures=20
between +1C and +5C.

Westerly flow continues today ahead of the first clipper with a
lull spreading east tonight through Wednesday night as the two
clippers cross. The strong single-banding persists from Lake
Ontario today with Day 1 PWPF for >8" additional after 12Z over 80%
in the Tug Hill Plateau. Day 2 PWPF for >6" is around 30% east of
Lake Erie and around 50% in the Tug Hill. Then LES resumes for the
northern Lakes with Day 3 PWPF for >6" over 90% in the Tug Hill.


...Southern Tier...
Starting Day 3...

Southern stream low pressure pushes inland over the northern Baja
California Friday with broad cyclonic flow out ahead which opens up
Gulf moisture to surge over Arctic-sourced air spilling down the
Plains from the Hudson Bay vortex. Broad areas of heavy wintry
precip are expected to develop on Friday over Texas to the
Southeast. Confidence is high for this event occurring though
details on how much winter accumulations, types, and locations have
uncertainty mainly derived from the timing of the southern stream
wave surging inland. Key Messages on this storm and the extreme
cold are active and linked below.=20



Jackson



...Extreme Cold Key Messages and Southern Tier Winter Storm Key=20
Messages are linked below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!66kif1vnRkDxDwdhyvRANP2JpfKbLwHYpkGOMDg3cQ-gJ= 5bEtdquSKelv5Dvb_Uca9AqyUzAP2URkWO8nhNKhH_ybR0$=20

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_2.png__;!!DZ3fjg!66kif1vnRkDxDwdhyvRANP2JpfKbLwHYpkGOMDg3cQ-gJ= 5bEtdquSKelv5Dvb_Uca9AqyUzAP2URkWO8nhNKUKiHd1s$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 202058
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
358 PM EST Tue Jan 20 2026

Valid 00Z Wed Jan 21 2026 - 00Z Sat Jan 24 2026


...Northern Plains, Upper Midwest, Great Lakes...=20
Days 1-3...

Sprawling Hudson Bay vortex dominates the continental pattern
through this week. Within the broad cyclonic pattern, a shortwave=20
and developing surface wave is forecast to traverse the Upper=20
Midwest tonight. Tonight, a corridor of warm advection and=20
associated 850-700 mb frontogenesis on the northeast flank of the
low center will drive an east-west oriented snow band spreading=20
from the Northern Plains into the Upper Midwest. The latest PWPF
for >4" is 20-30% over northwest IA and southern WI, which=20
increases to 50-75% over southwestern MI. By tomorrow, a modest
clipper system following behind the lead wave will drive additional
snowfall, although the QPF footprint with this system is markedly
lower. Meanwhile, strong single-banding will gradually come to an=20
end tonight downwind of Lake Ontario. Even so, the Day 1 PWPF for=20

6" is around 50% in the Tug Hill Plateau, which ramps up to above=20

90% by Day 3 with the approach of a strong Arctic high from the=20
west.

Asherman/Jackson

...Southern Plains to Lower MS Valley...
Day 3...

....Major Winter Storm To Begin Impacting the South Central U.S.=20
on Friday...

The highly anticipated winter storm that is expected to impact much
of the southern and eastern U.S. this weekend begins on Friday. To
produce a winter storm of this size and magnitude, the weather
pattern must have a very cold air-mass anchored to the north. In
this case, a near record-breaking dome of high pressure to the
north is filtering in a frigid air-mass throughout much of the
eastern two-thirds of the CONUS. Meanwhile, an upper trough off the
California coast will direct subtropical East Pacific moisture at
the Southern Plains. Persistent Pacific moisture overrunning an
arctic air-mass will result in not only snow, but treacherous sleet
and freezing rain from southern Texas to the Lower MS Valley.=20
Exact placement of the wintry mix zone remains unclear as guidance=20
is adjusting how strong the WAA aloft will be, but confidence is=20
growing in Friday morning being the starting point for wintry=20
precipitation. The latest WSO through Friday afternoon (D4 WSO=20
shows a large footprint of >50% odds for a warning-level snowfall=20
event from the TX Panhandle on east through much of OK and into=20
central AR. Farther south, heavy sleet and hazardous freezing rain=20
will be more common in the heart of Texas on east to the ArkLaTex.=20
This storm will have wide reaching impacts through the Mid-South=20
and all the way to the East Coast by this weekend. Residents=20
affected by this storm should continue to monitor the forecast=20
through their local warning forecast office at weather.gov.=20


Mullinax



...Winter Storm Key Messages are in effect. Please see current=20
Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!97DbUNAoUxdcCZ0op6hRdmQMMIqdMz9bPUdDmexpzgKBo= UoyobGpTezL1K6VO3Vj0OtgEnw3C8SsVqJqr9URmM_gz14$=20

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_2.png__;!!DZ3fjg!97DbUNAoUxdcCZ0op6hRdmQMMIqdMz9bPUdDmexpzgKBo= UoyobGpTezL1K6VO3Vj0OtgEnw3C8SsVqJqr9UR0mK2zF8$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 210923
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
423 AM EST Wed Jan 21 2026

Valid 12Z Wed Jan 21 2026 - 12Z Sat Jan 24 2026


***At Least Major Winter Storm Impacts The South Friday Through=20
This Weekend, Expanding Up The East Coast Saturday Night***

...Southern Rockies, Southern Plains, Through the Mid-South and
Gulf Coast into The Tennessee Valley...=20
Days 2-3...

Precip onset for major winter storm Friday on the Southern Plains=20
and Southern Rockies, quickly intensifying and expanding east over
the Mid-South and Gulf Coast states into the Tennessee Valley=20
Saturday. Expansive cold air mass spills down the Plains Thursday=20
night from 1052mb high pushing into North Dakota. Meanwhile, a=20
cutoff low under a deep ridge off the West Coast approaching=20
southern CA Thursday gets absorbed into the flow of a northern=20
stream trough dropping down the northern Rockies Friday making the=20
united trough full-latitude (through the length of the CONUS) by=20
Saturday. Subtropical East Pacific moisture ahead of the low trough
will spread across northern Mexico with Gulf moisture surging=20
north as early as Thursday night. Persistent Pacific and Gulf=20
moisture overrunning the arctic-sourced airmass will result the=20
full wintry p-type scenario from plain rain near the Gulf Coast to=20
freezing rain not too far inland, to sleet north of that and=20
finally snow where the warm nose remains subzero. The main notes=20
for the 00Z cycle is a northward shift in both QPF and the thermal=20 profiles/warm nose. However, the surface cold air should continue=20
to progress so in a sense the broadness of the winter weather swath
is still expanding (stretching from the Gulf Coast to the central=20
Plains). The precip intensification Friday night through Saturday=20
will be remarkable over the southern Plains and Mid-South with=20
heavy rates and likely catastrophic impacts for at least local=20
scales given the risk for over an inch of ice accretion and deep=20
snow with heavy sleet in between. Residents should prepare for=20
prolonged power outages that occur during the coldest air of the=20
season. Please monitor the forecast for your area via weather.gov.=20
With so much heavy precip occurring just after the WWD time range=20
ending 12Z Saturday, probabilities will be presented through 00Z=20
Sunday (Day 3.5). Day 3.5 PWPF for > 8" is 50-80% across much of=20
the central/southern CO Rockies through the central NM ranges with=20
a wide swath of 20-50% from much of OK, northern AR along the TN/KY
border to the southern Appalachians. Day 3.5 PWPF for >0.5" is=20
20-50% from northeast TX across the LA/AR border and northern MS=20
and northwest AL.=20


...Great Lakes...=20
Days 1-3...

Sprawling Hudson Bay vortex dominates the continental pattern
through this week. Within the broad cyclonic pattern, a pair of=20 shortwaves/clippers cross the Great Lakes through tonight with=20
associated 850-700 mb frontogenesis driving east-west oriented=20
snow bands over WI again and the Great Lakes. Day 1 PWPF for >4"=20
is 50% over southwest MI, northwest PA/western NY and over the Tug
Hill and Mohawk Valley. Northern lake LES continues then through
Friday. Day 2 PWPF for >4" is 50-80% for the Keweenaw and eastern=20
U.P., northern L.P., and the Tug Hill to the western Adirondacks.=20
These values diminish Saturday under surface ridging under the core
of the Arctic cold.


Jackson


...Winter Storm Key Messages remain in effect for extreme cold and
a major winter storm for the south. They are linked below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!6TkyJsUVAAqGEjMXf63mjHBuW427QXBU54gcPNA4JaazV= CZVSrgAWf2a7OjMjHN5lztAe-3wWz8lG44mcV-Fe50kOA0$=20

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_2.png__;!!DZ3fjg!6TkyJsUVAAqGEjMXf63mjHBuW427QXBU54gcPNA4JaazV= CZVSrgAWf2a7OjMjHN5lztAe-3wWz8lG44mcV-F-DbOOYI$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 212105
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
405 PM EST Wed Jan 21 2026

Valid 00Z Thu Jan 22 2026 - 00Z Sun Jan 25 2026


***Major Winter Storm To Bring Significant Impacts To The South
Friday Through This Weekend, Expanding Up The East Coast Saturday
Night Into Sunday***

...Southern Rockies, Southern Plains, Gulf Coast, Mid-South,
Southern & Central Appalachians, & Mid-Atlantic...
Days 2-3...

The ingredients for the impending major winter storm begin to take
shape Thursday night. A broad upper trough located off Baja
California will work in tandem with a ridge axis near Mexico to
direct a rich plume of tropical East Pacific moisture into the
Southern Rockies and Plains. At the same time, an arctic front
ushers in the coldest temperatures this season across the Great=20
Plains with a highly anomalous dome of arctic high pressure=20
building in over the North Central U.S.. As high pressure rushes=20
south, easterly upslope flow induced between the high pressure to=20
the north and lower pressure near California will cause upslope=20
flow into the higher terrain of the CO and NM Rockies with lighter=20
snowfall in the central High Plains. WPC probabilities show high=20
chances (>70%) for snowfall above 9,000ft in the CO/NM Rockies=20
through Saturday afternoon.

Precipitation will blossom over much of KS, OK, and TX Friday, starting
as rain across much of TX initially, but look for precipitation to
transition to snow over KS, northern OK, and the TX Panhandle by=20
Friday afternoon and evening. Farther south, strengthening low-=20
level WAA will over-run the incoming sub-freezing layer in the=20
lowest 2,000ft of the atmosphere from West Texas to as far east as=20
the Mid-South. Sleet will become more prevalent over the Red River=20
Valley, north-central AR, and into western TN, while freezing rain
is the primary preip type from the TX Hill Country through the=20
ArkLaTex and as far east as the TN Valley. Heavy sleet is possible
in some of these areas with multiple inches of sleet possible
through Saturday. The slow progression of the upper trough over=20
Baja California and the bitterly cold arctic air-mass anchored=20
over the eastern two-thirds of the CONUS is a recipe ripe for=20
prolonged freezing rain from central TX to as far east as the=20
southern Appalachians through 00Z Sunday. WPC probabilities show=20 concerningly high probabilities (50-70%) for ice accumulations=20
through 00Z Sunday over one-quarter inch. The areas of greatest=20
concern are over the ArkLaTx, southern AR, northern LA, northern=20
MS/AL, and southern TN where low-to-moderate chances (30-50%)=20
exist for over one-half inch of ice. While this discussion is=20
geared to the short term (ending 00Z Sunday) the ice in all these=20
areas are forecast to continue through Saturday night and even into
Sunday. There is great concern for extensive tree damage and power
outages from central TX on east through the Mid-South and into the
Southern Appalachians into Sunday.

Farther north, the air-mass through the depth of the atmospheric
column remains cold enough to support all snow from the Central
Plains on east through the Ozarks and across northern TN and much
of KY beginning Friday evening in the Plains, then into the TN/OH
Valleys Saturday morning. By midday and into Saturday afternoon,
periods of snow will reach the southern and central Appalachians
and potentially the VA/NC Piedmont. Snowfall rates topping 1"/hr=20
are likely in areas just north of the strongest 850-700mb FGEN=20
zone and vertical velocities are highest in a highly saturated=20
dendritic growth zone in the Central Plains and OH Valley. The=20
very cold temperatures over KS on east through MS and into the OH=20
Valley will cause SLRs to range anywhere from between 12-18:1 with=20
the higher SLRs over KS. WPC probabilities through 00Z Sunday=20
depict high chances (>70%) for >4" of snow over central and=20
southern KS, much of northern OK, the TX Panhandle, and into the=20
Ozarks of northern AR and southern MO. The best chances for >8" of=20
snowfall reside over the Ozarks where moderate chance probabilities
(40-60%) are present.=20

Similar to the ice, the snow will by no means be over given the=20
extensive plume of anomalous moisture emanating out of the East=20
Pacific. By Saturday night, southerly flow out of the Gulf will=20
continue to direct copious amounts of moisture into the eastern
U.S., resulting in a highly disruptive and dangerous winter storm
from the Mid-South to the Mid-Atlantic. WPC continues to issue Key
Messages for this winter storm and a link to them can be found
below.


...Great Lakes...=20
Days 1-3...

A Hudson Bay vortex pivoting south through Ontario will sustain the
seemingly endless cyclonic flow over the Great Lakes and their
usual snow belts. 500mb heights associated with this powerful upper
low are quite anomalous (below the 1st climatological percentile
in southern Ontario Thursday into Friday night). WPC probabilities
highlight high chances (>70%) for snowfall totals >4" over the
northern tier of the U.P., western MI, along the Chautauqua Ridge
on north into western NY, and down wind of Lake Ontario over the
Tug Hill. The Tug Hill most notably will continue to receive very
heavy snow over the next few days highlighted by WPC 72-hour
probabilities sporting high chances (>70%) in the Tug Hill. A
growing concern is for snow squalls over the Northeast. WPC
initiated Key Messages for what appear to be multiple rounds of
snow squalls from western NY on east through New England, with=20
some squalls possible as far south as northern PA. The final round
of squalls are expected on Friday as an arctic front traverses the
region, causing steep lapse rates and focused vertical ascent. For
more details on the snow squall threat in the Northeast through
Friday, please refer to our Key Messages.


Mullinax



...Winter Storm Key Messages are in effect. Please see current=20
Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!4leUoWpjIV7yE2h8DceGN34RPg1d4yvNkmbTFjbw31Qzn= tpehh7jECz3HdwJRagEcw4-6zFuFEKoWCJC7xOHFH7tjJY$=20

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_2.png__;!!DZ3fjg!4leUoWpjIV7yE2h8DceGN34RPg1d4yvNkmbTFjbw31Qzn= tpehh7jECz3HdwJRagEcw4-6zFuFEKoWCJC7xOHAW-kv9A$=20

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_3.png__;!!DZ3fjg!4leUoWpjIV7yE2h8DceGN34RPg1d4yvNkmbTFjbw31Qzn= tpehh7jECz3HdwJRagEcw4-6zFuFEKoWCJC7xOHnzl7X1Y$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 220845
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
345 AM EST Thu Jan 22 2026

Valid 12Z Thu Jan 22 2026 - 12Z Sun Jan 25 2026


***Significant Winter Storm To Bring Potentially Crippling Impacts
To Parts Of The South Friday Through This Weekend, Expanding Up=20
The East Coast Saturday Night Into Sunday***

...Southern Rockies and Southern Plains through the Ohio/Tennessee
Valleys into the Mid-Atlantic...
Days 2-3...

Estimated over 130 million residents under winter weather headlines
this morning as confidence continues to increase on a highly=20
impactful and extremely wide- reaching winter storm to begin on=20
Friday across the south-central U.S., eventually pushing towards=20
the East Coast by Saturday night into Sunday. Guidance has nearly=20 unanimously converged on the upper low churning just west of=20
southern CA (sampled by recon aircraft for the recent 00z model=20
suite) to eject eastward ahead of a diving northern stream=20
shortwave and fully phase by the day 4 timeframe. Uncertainty=20
remains associated with the speed of the approaching northern=20
stream trough, which eventually leads to the amplified pattern in=20
the central/eastern U.S.. However, this uncertainty has decreased=20
tonight as guidance converges on cluster 1 from WPC's 12z 1/21=20
clusters. Some guidance remains more amped (CMC/ECMWF) than others=20
(GFS) and leads to some lingering uncertainty regarding the=20
northern extent of heavy QPF and the mid- level warm nose. However,
all scenarios now point to a large QPF footprint falling in the=20
form of frozen precipitation and resulting in a significant winter
storm.

The aforementioned southern CA upper low will help surge ample=20
Pacific moisture (above the 90th climatological percentile per the=20
12z NAEFS) into the southern U.S. by Friday night, where a deep=20
arctic airmass is placed in ideal position for overrunning and=20
wintry precipitation. This arctic airmass in place is brought to=20
the region by a near record 1050mb surface high pressure over the=20
Northern Plains on Friday. As time progresses this high pressure is
expected to moderate and evolve into more of a "banana" look,=20
which is classic for heavy winter precipitation in the East as
low-levl cold air continues to sink southward towards a stationary
front forecast to stretch along the Gulf Coast. A few weak areas of
low pressure are forecast to form along this front before gradually
lifting northward into the TN Valley and along the Carolina=20
coastline by the end of D3. Decided to split up the remainder of=20
the discussion into hazard- type categories given this event covers
such a massive amount of real- estate. For local forecasts and=20
more details, read your local WFOs AFD.

Heavy Freezing Rain/Sleet...
Arguably the most lasting impact associated with this winter storm
could be from heavy accumulating freezing rain and sleet=20
stretching from the southern Plains, Mid-South, Tennessee Valley,=20
and southern Mid- Atlantic. This is due to very cold low-level=20
arctic air being reinforced by the strong high over the north-=20
central U.S. and a warm nose aloft (at around 750mb per cross=20
section model soundings) melting snow as it falls through the=20
column before refreezing just before or at the surface. The=20
greatest freezing rain amounts and impacts are currently forecast=20
across northeast TX through northern MS as favorable thermal=20
profiles linger for over 24 hours beginning Friday night. WPC=20
72-hour probabilities for >0.5" of freezing rain are high >70%=20
across southern AR into parts of northwest MS. Here, ice accretion=20
could be crippling and exceed 0.75-1.00", which would very likely=20
lead to widespread long- lasting damage to infrastructure,=20
including power outages and tree damage. Major sleet accumulations
are also likely just north of the freezing rain area stretching=20
from southern OK/north TX through central AR and into the Mid-
South, with more than a few inches of sleet possible. This could=20
make for treacherous driving conditions and lasting travel impacts=20
due to the bitterly cold airmass expected to linger into next week=20
over the region.

Heavy icing is also likely into the TN Valley and nearby southern=20 Appalachians and Mid- Atlantic, where freezing rain continues=20
beyond the D3 timeframe. The setup across the southern Mid-Atlantic
down as far south as northern GA and areas just inland from the=20
coasts of the Carolinas is an extreme case of CAD with a 1040mb=20
high situated over the Interior Northeast on Saturday night. This=20
high pressure filters very low/dry dew points with values below
zero prior to precip onset late Saturday. This cold air wedge
remains sharply locked in place at the surface for the remainder=20
of the event as 700-850mb temperatures begin to increase well above
freezing by the end of D3 throughout the Carolinas and northern=20
GA. WPC probabilities for >0.25" of freezing rain accretion through
12z Sun. are currently 40-70% from northern AL/TN through northern
GA and into the Midlands of SC and areas just inland of the NC=20
Tidewater region. Heavy sleet accumulations are also possible where
the low-level column remains colder into VA Piedmont.

Heavy Snow...
North of the mixed precipitation area and closely tide to both a=20
favorable LFQ of a zonally oriented 180kt upper jet and strong=20
700mb fgen, snow is the primary precipitation type stretching from=20
the southern High Plains of east-central NM and the southern=20
Rockies through the Plains, Mid-Mississippi Valley, Ohio Valley,=20
and Mid-Atlantic by Sunday morning. Favorable upslope flow as the=20
strong arctic high pressure noses southward along the High Plains=20
starts on Friday across the southern Rockies, with light snow and=20
even a chance for freezing drizzle at onset across the central=20
Plains until the column fully saturates. Heavy snow is then=20
forecast to begin breaking out Friday night from the=20
central/southern Plains through the mid-Mississippi Valley and=20
spanning much of the Ohio Valley and parts of the Midwest on=20
Saturday. Snowfall rates could near 1"/hr as strong lift intersects
with a region about 150 miles north of the mixed precip zone where=20
the DGZ is forecast to be extremely deep (about 500 mb per areal=20
average soundings). This would allow for efficient formation of=20
dendrites where ample lift can fully moisture the column. Should a=20
region remain in this zone for a longer enough period it's not out=20
of the realm of possibility 30:1 snow ratios are observed.=20
However, most locations appears to progressively see this favorable
DGZ move east-northeast with time and shrink as mid-level=20
temperatures increase above -8C and allows for more needles than=20
dendrites. WPC probabilities for >6" of snow through 12z Sun. are=20
medium to high (30-70%) stretching from east-central NM and the TX=20
Panhandle across northern OK, into the Mid-Mississippi Valley.=20
These probabilities increase to above 70% in the Ohio Valley,=20
where 8-10" of snow is possible. The widespread nature of this
heavy snow is likely to significantly impact both ground and air
travel in the region.

One area that is slowly becoming the most favorable location for=20
heavy snowfall rates and potentially the most impressive snowfall=20
amounts is the central Appalachians, northern VA, MD, and southern=20
PA through early Sunday. As the upper level trough deepens over the
central U.S. Saturday night, mid- level flow begins to increase=20
out ahead of it and meets the mid-level warm front stretching from
the eastern Ohio Valley into the Mid- Atlantic. Several 00z models
highlight increasing 700mb fgen over the eastern Ohio Valley and=20
into central VA by late D3, which supports the potential for an=20
extended period of 1"/hr rates across much of eastern WV,=20
central/northern VA, MD, and southern PA. The 0C warm nose may=20
begin to approach northern VA by the end of D3, but areas just to=20
the north could see 6-12" by sunrise on Sunday as precipitation=20
lingering further into the day on Sunday. Snow ratios will also be
favorable at onset and could potentially exceed 20:1 within
enhanced banding, which is well above the 11:1 climatology in the
region. Current WPC probabilities through D3 are medium to high=20
(40-70%) for at least 8" of snow, this includes areas just west of=20
I-95 from D.C. to Baltimore. Heavy snow is expected to continue=20
stretching into the Northeast and New England on Sunday, see WPC's=20
Extended Forecast Discussion for more. Also, see the Key Messages=20
linked at the bottom of this discussion.


...Great Lakes...=20
Days 1-2...

A Hudson Bay vortex pivoting south through Ontario will sustain the
seemingly endless cyclonic flow over the Great Lakes and their
usual snow belts before strong high pressure builds overhead on D3
and ends this lake effect pattern for the time being. 500mb=20
heights associated with this powerful upper low are quite anomalous
(below the 1st climatological percentile per 12z NAEFS in southern
Ontario Thursday into Friday night). WPC probabilities highlight=20
medium-high chances (>60%) for snowfall totals >6" over the=20
northern tier of the U.P., along the Chautauqua Ridge on north=20
into western NY, and down wind of Lake Ontario over the Tug Hill.=20
The Tug Hill most notably will continue to receive very heavy snow=20
over the next few days highlighted by WPC 48-hour probabilities=20
sporting high chances (>70%) for >8" in the Tug Hill.=20

A growing concern is for snow squalls over the Northeast. WPC=20
initiated Key Messages for what appear to be multiple rounds of=20
snow squalls from western NY on east through New England, with some
squalls possible as far south as northern PA early today. This is
highlighted well in CAMs snow squall parameter, with highest
potential on Thursday from western PA through central NY. The=20
final round of squalls are expected on Friday as an arctic front=20
traverses the region, causing steep lapse rates and focused=20
vertical ascent. This front will also usher dangerously cold
temperatures and wind chills. For more details on the snow squall=20
threat in the Northeast through Friday, please refer to our Key=20
Messages.


Snell




...Winter Storm/Snow Squall/Extreme Cold Key Messages are in=20
effect. Please see current Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!4SOx9iXiM3PgwTKiPMC2-PfsGt8BJz0BBMMz9h4kUUIjD= IQTQvpLmpBzti1jhxxLn8WLhLWkb5WyZSxjoet_GDZdtno$=20

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_2.png__;!!DZ3fjg!4SOx9iXiM3PgwTKiPMC2-PfsGt8BJz0BBMMz9h4kUUIjD= IQTQvpLmpBzti1jhxxLn8WLhLWkb5WyZSxjoet_AHZ3rCs$=20

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_3.png__;!!DZ3fjg!4SOx9iXiM3PgwTKiPMC2-PfsGt8BJz0BBMMz9h4kUUIjD= IQTQvpLmpBzti1jhxxLn8WLhLWkb5WyZSxjoet_3CqF82U$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 221959
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
259 PM EST Thu Jan 22 2026

Valid 00Z Fri Jan 23 2026 - 00Z Mon Jan 26 2026


...Major winter storm to bring the potential for crippling icing,=20 significant sleet, and heavy snow from the Southern Plains through=20
the Southeast and up the Atlantic Coast into New England...

The event will begin Friday morning across the Southern Plains. The
driver of this event is an impressive overlap of intensifying
synoptic ascent with increasing subtropical moisture.=20

The synoptic pattern becomes favorable Friday in response to the
evolution of multiple shortwaves rotating through an amplifying
trough across the eastern CONUS. A closed 500mb low off the Baja
Peninsula will begin to open and shear to the east, at the same
time dual shortwaves dig out of Saskatchewan/Alberta and into the
Northern Plains. As the northern shortwaves dive south and the Baja
low ejects east, the interaction of these features will lead to
increasing mid-level divergence overlapping pronounced height falls
to produce rich deep layer lift. This will be on top of an arctic
cold front that will be sagging southward into the Southern Plains
and eventually work its way southeast to the Gulf and Atlantic
coasts by Saturday. This overlapping ascent will materialize atop a
moistening column as subtropical moisture downstream of the Baja
low streams northeast reflected by IVT that reaches above the 97th
percentile according to NAEFS, in a broad swath from Texas to the
Carolinas, with above the record (CFSR at 00Z) climatology by
Sunday evening in the east.=20

This increasing moisture will result in a large swath of
precipitation expanding from the Southern Plains Friday, to the
Mississippi Valley and Tennessee Valley Saturday, into the
Carolinas and Mid-Atlantic by Sunday, and finally reaching the
Northeast Sunday night. This is a very large and impactful system
across a huge portion of this country. While impacts will be
considerable in many areas (aided by extreme cold), the icing (and
sleet) and snow will be most impressive across two distinct areas.

Freezing Rain and Sleet:
Arguably the most lasting impact associated with this winter storm
could be from heavy accumulating freezing rain and sleet stretching
from the southern Plains, Mid- South, Tennessee Valley, and
southern Mid-Atlantic. This is due to very cold low-level arctic
air being reinforced by the strong high over the north-central U.S.
(and enhanced by pronounced mid-level confluence over the Great
Lakes and New England) and a warm nose aloft (at around 750mb per
cross section model soundings) melting snow as it falls through the
column before refreezing just before or at the surface,and in some
places this re-freezing layer is above the 90th percentile in terms
of depth, suggesting some locations will experience exceptional
sleet accumulations.=20

The greatest freezing rain amounts and impacts are currently=20
forecast across northeast TX through northern MS as favorable=20
thermal profiles linger for over 24 hours beginning Friday night.=20
WPC 72-hour probabilities for >0.5" of freezing rain are high >70%=20
across southern AR into parts of northwest MS. Here, ice accretion=20
could be crippling and exceed 0.75-1.00", (WPC probabilities above
50% for 1" if ice) which would almost certainly lead to widespread
long-lasting damage to infrastructure, including power outages and
tree damage. Major sleet accumulations are also likely just north=20
of the freezing rain area stretching from southern OK/north TX=20
through central AR and into the Mid- South, with more than a few=20
inches of sleet possible. The consistency of the guidance in both=20
placement and amounts for this area are resulting in high=20
confidence in an extreme event, leading to long-lasting impacts=20
both to travel and infrastructure due to the bitterly cold airmass=20
expected to linger into next week over the region.

Heavy icing is also expected farther east into the southern=20
Appalachians and southern Mid-Atlantic. The setup across the=20
southern Mid- Atlantic down as far south as northern GA and areas=20
just inland from the coasts of the Carolinas is an extreme case of=20
CAD with a 1040mb high situated over the Interior Northeast on=20
Saturday night. While regional soundings indicate there may be
considerable sleet in this area as well, especially across southern
VA into northern NC, these CADs are notorious for their effective dry/isallobaric flow, enhanced by precipitation, leading to dry
wet-bulb advection offsetting the latent heat of freezing during
freezing rain. With such an impressive high in place at
precipitation onset, this will likely result in considerable
accumulations of sleet and freezing rain here, too, with WPC
probabilities indicating a moderate risk (50-70%) of at least 0.5",
highest across the Piedmont. The guidance has trended just a bit
colder this afternoon, but significant icing is also possible as
far north as Richmond, VA and towards the Chesapeake Bay.


Heavy Snow:
North of the mixed precipitation area and closely tied to both a
favorable LFQ of a zonally oriented 180kt upper jet and strong
700mb fgen, snow is the primary precipitation type stretching from
the southern High Plains of east-central NM and the southern
Rockies through the Plains, Mid-Mississippi Valley, Ohio Valley,
Mid-Atlantic, and reaching the Northeast by Sunday evening (with
additional expansion beyond this forecast period).=20

Favorable upslope flow as the strong arctic high pressure noses=20
southward along the High Plains behind a strong cold front starts=20
on Friday across the southern Rockies, with light snow and even a=20
chance for freezing drizzle at onset across the central Plains=20
until the column fully saturates. Heavy snow is then forecast to=20
begin breaking out Friday night from the central/southern Plains=20
through the mid-Mississippi Valley and spanning much of the Ohio=20
Valley and parts of the Midwest on Saturday. Snowfall rates could=20
near 1"/hr as strong lift through WAA/fgen intersects with a=20
region where the DGZ is forecast to be extremely deep (SREF
probabilities above 70% for >100mb of depth). This would allow for
efficient formation of dendrites where ample lift can fully=20
moisture the column. While this depth is impressive, regional
forecast soundings indicate that the best ascent may lie below this
DGZ in many areas, and there is only modest indication of any
isothermal layer beneath the DGZ to maintain aggregates. Despite
this, efficient and fluffy SLRs are likely in this area, and with a
long duration event expected, WPC probabilities are moderate
(30-50% )for at least 12 inches from eastern KS and OK into=20
southern MO, with widespread 4+ inches extending all the way back
into the TX Panhandle and lower MS VLY.

Farther east, some heavier snowfall is becoming more likely for
parts of the Ohio Valley, and into the Mid-Atlantic, and especially
Northeast. Here, pronounced WAA and accompanying 850-700mb fgen
will drive pronounced ascent into a rapidly moistening column
thanks to IVT above the 90th climatological percentile. As the
upper trough (interaction of the southern and northern streams)
deepens over the Plains, downstream ascent will maximize and a
period of impressive WAA snow with snowfall rates >1"/hr are
likely. As secondary low pressure develops offshore (in a Miller B
type evolution), banded structures within the WAA are likely to
translate northward from the Mid-Atlantic into New England, and
then may pivot and drift eastward Sunday night into Monday. Where
this occurs, the heaviest total snowfall accumulations are
probable, reflected by WPC probabilities that are already above 50%
for 12+ inches, and this is even with more of the event beyond this
forecast period (into New England). While there is some uncertainty
into how much mixing will pivot northward, especially closer to the
coast from Richmond, VA through Long Island, the interior portions
(NW of I-95 and into southern New England which will remain cold as
the secondary low develops and tracks near the 40/70 Benchmark)
will remain all snow with above-climo SLRs leading to significant
snowfall accumulations. Many areas are expected to receive more
than 12 inches from the Ohio Valley through the Mid-Atlantic and
into the Northeast before this system winds down on Monday /D4/.

Key Messages for this system are linked below (Key Message 2)


...Great Lakes...=20
Days 1-2...

Expansive mid-level low centered over the Hudson Bay will track
slowly southward this evening and then begin to shear open and
translate to the east as a secondary shortwave rotates through its
base and atop the Great Lakes Friday evening. Behind this impulse,
shortwave ridging will amplify across the area, bringing an end to
the persistent CAA and associated lake-induced ascent.

The subsequent W/NW flow and accompanying CAA will lead to
impressive lake effect snow (LES) in the favored W/NW snow belts
D1, with some pivoting to more N/NW D2 before waning. The heaviest
snowfall is likely east of Lake Ontario D1 where WPC
probabilities indicate a high risk (>70%) for at least 12 inches,=20
and 1-2 feet is possible across the Tug Hill Plateau. Elsewhere,=20
WPC probabilities suggest a moderate risk (50-70%) for at least 4=20
inches along the Chautauqua Ridge, western MI (east shore of Lake=20
Michigan) and across the northern U.P. During D2 the precipitation=20
intensity will weaken, but WPC probabilities suggest a moderate=20
risk (30-70%) for at least 2 inches in far NW IN and southeast of=20
Lake Ontario, before the shortwave ridging brings an end to this=20
round of LES.

Additionally, and this pivots into the Northeast as well, a second
round of snow squalls is possible on Friday along and behind an
arctic cold front traversing the region. For more details on the=20
snow squall threat in the Northeast through Friday, please refer to
our Key Messages (Key Messages 3) below.


Snell/Weiss





...Winter Storm Key Messages are in effect. Please see current=20
Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!-ZbcCxUHFaZzUCjVjcXjC8-1-t_ZYP0Ds_0gTb0a3UKg7= LWejAi__n66qDCj_90esw97-mNA9zZNPcoKLnZx6xUubt8$=20

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_2.png__;!!DZ3fjg!-ZbcCxUHFaZzUCjVjcXjC8-1-t_ZYP0Ds_0gTb0a3UKg7= LWejAi__n66qDCj_90esw97-mNA9zZNPcoKLnZx7Mmwhog$=20

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_3.png__;!!DZ3fjg!-ZbcCxUHFaZzUCjVjcXjC8-1-t_ZYP0Ds_0gTb0a3UKg7= LWejAi__n66qDCj_90esw97-mNA9zZNPcoKLnZx13dN6Ms$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 230858
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
358 AM EST Fri Jan 23 2026

Valid 12Z Fri Jan 23 2026 - 12Z Mon Jan 26 2026


...Major winter storm to bring the potential for crippling icing,=20 significant sleet, and heavy snow from the Southern Plains through=20
the Southeast and up the Atlantic Coast into New England...

Forecast remains largely on track with only minor changes compared
to the previous cycle, with typical uncertainties surrounding the=20
depth and northern push of the mid-level warm nose. While this=20
uncertainty is rather minor from a synoptic scale, local forecasts=20
can still be drastically impacted by this feature. The event will=20
begin this morning across the Southern Plains and expand towards
the MS VLY tonight. The driver of this winter storm is an=20
impressive overlap of intensifying synoptic ascent with increasing=20 subtropical moisture.

The synoptic pattern becomes favorable today in response to the=20
evolution of multiple shortwaves rotating through an amplifying=20
trough across the eastern CONUS. A closed 500mb low off the Baja=20
Peninsula will begin to open and shear to the east, at the same=20
time dual shortwaves dig out of Saskatchewan/Alberta and into the=20
Northern Plains. As the northern shortwaves dive south and the Baja
low ejects east, the interaction of these features will lead to=20
increasing mid-level divergence overlapping pronounced height falls
to produce rich deep layer lift. The northern shortwave has=20
trended a tad slower with overnight guidance and allows for more
ridging out ahead of this system, helping shift the mid-level warm
nose farther north. Regardless, the impressive ascent will be on=20
top of an arctic cold front that will be sagging southward into the
Southern Plains and eventually work its way southeast to the Gulf=20
and Atlantic coasts by Saturday. This overlapping ascent will=20
materialize atop a moistening column as subtropical moisture=20
downstream of the Baja low streams northeast reflected by IVT that=20
reaches above the 97th percentile according to NAEFS, in a broad=20
swath from Texas to the Carolinas, with above the record (CFSR at=20
00Z) climatology by Sunday evening in the east.

This increasing moisture will result in a large swath of
precipitation expanding from the Southern Plains today, to the=20
MS VLY and TN VLY Saturday, into the Carolinas and Mid- Atlantic=20
by Sunday, and finally reaching the Northeast Sunday night. This is
a very large and impactful system across a huge portion of this=20
country. While impacts will be considerable in many areas (aided by
extreme cold), the icing (and sleet) and snow will be most=20
impressive across two distinct areas.

Freezing Rain and Sleet:
Arguably the most lasting impact associated with this winter storm
could be from heavy accumulating freezing rain and sleet stretching
from the Southern Plains, Mid- South, Tennessee Valley, and=20
southern Mid-Atlantic. This is due to very cold low-level arctic=20
air being reinforced by the strong high over the north-central U.S.
(and enhanced by pronounced mid-level confluence over the Great=20
Lakes and New England) and a warm nose aloft (at around 750mb per=20
cross section model soundings) melting snow as it falls through the
column before refreezing just before or at the surface,and in some
places this re-freezing layer is above the 90th percentile in=20
terms of depth, suggesting some locations will experience=20
exceptional sleet accumulations.=20

The greatest freezing rain amounts and impacts are currently=20
forecast across northeast TX through northern MS as favorable=20
thermal profiles linger for over 24 hours beginning Friday night.=20
WPC 72-hour probabilities for >0.5" of freezing rain are high >70%=20
across southern AR/northern LA into parts of northern MS. Here,=20
ice accretion could be crippling and exceed 0.75-1.00", (WPC=20
probabilities 40-50% for 1" of ice) which would almost certainly=20
lead to widespread long-lasting damage to infrastructure, including
power outages and tree damage. Major sleet accumulations are also=20
likely just north of the freezing rain area stretching from=20
southern OK/north TX through central AR and into the Mid- South,=20
with more than a few inches of sleet possible. The consistency of=20
the guidance in both placement and amounts for this area are=20
resulting in high confidence in an extreme event, leading to long-=20
lasting impacts both to travel and infrastructure due to the=20
bitterly cold airmass expected to linger into next week over the=20
region.

Heavy icing is also expected farther east into the southern=20
Appalachians and southern Mid-Atlantic. The setup across the=20
southern Mid- Atlantic down as far south as northern GA and areas=20
just inland from the coasts of the Carolinas is an extreme case of=20
CAD with a 1040mb high situated over the Interior Northeast on=20
Saturday night. While regional soundings indicate there may be
considerable sleet in this area as well, especially across southern
VA into northern NC, these CADs are notorious for their effective dry/isallobaric flow, enhanced by precipitation, leading to dry
wet-bulb advection offsetting the latent heat of freezing during
freezing rain. With such an impressive high in place at
precipitation onset, this will likely result in considerable
accumulations of sleet and freezing rain here, too, with WPC
probabilities indicating a moderate-to-high risk (60-80%) of at=20
least 0.5", highest across the Piedmont and northern GA. The=20
guidance has trended just a bit colder this afternoon, but=20
significant icing is also possible as far north as Richmond, VA and
towards southern MD.

Heavy Snow:
North of the mixed precipitation area and closely tied to both a
favorable LFQ of a zonally oriented 180kt upper jet and strong
700mb fgen, snow is the primary precipitation type stretching from
the southern High Plains of east-central NM and the southern
Rockies through the Plains, Mid-Mississippi Valley, Ohio Valley,
Mid-Atlantic, and reaching the Northeast by Sunday evening (with
additional expansion beyond this forecast period).=20

Favorable upslope flow as the strong arctic high pressure noses=20
southward along the High Plains behind a strong cold front starts=20
on Friday across the southern Rockies, with light snow and even a=20
chance for freezing drizzle at onset across the central Plains=20
until the column fully saturates. Heavy snow is then forecast to=20
begin breaking out Friday night from the central/southern Plains=20
through the mid-Mississippi Valley and spanning much of the Ohio=20
Valley and parts of the Midwest on Saturday. Snowfall rates could=20
near 1"/hr as strong lift through WAA/fgen intersects with a=20
region where the DGZ is forecast to be extremely deep (SREF
probabilities above 70% for >100mb of depth). This would allow for
efficient formation of dendrites where ample lift can fully=20
moisture the column. While this depth is impressive, regional
forecast soundings indicate that the best ascent may lie below this
DGZ in many areas, and there is only modest indication of any
isothermal layer beneath the DGZ to maintain aggregates. Despite
this, efficient and fluffy SLRs are likely in this area, and with a
long duration event expected, WPC probabilities are moderate
(40-60% )for at least 12 inches from southeastern KS and
northeastern OK into southern MO, with widespread 4+ inches=20
extending all the way back into the TX Panhandle and lower MS VLY.
Trends have been more favorable for snow vs lately on D1 across
eastern OK and central AR as guidance depicts stronger mid-level
fgen and dynamic cooling aloft to keep the entire column below 0C.
00z HREF also depicts the potential for 1"/hr snowfall rates in
this region. Will monitor this for potential adjustments=20
downstream.

Farther east, some heavier snowfall is becoming more likely for
parts of the Ohio Valley, and into the Mid-Atlantic, and especially
Northeast. Here, pronounced WAA and accompanying 850-700mb fgen
will drive pronounced ascent into a rapidly moistening column
thanks to IVT above the 90th climatological percentile. As the
upper trough (interaction of the southern and northern streams)
deepens over the Plains, downstream ascent will maximize and a
period of impressive WAA snow with snowfall rates >1"/hr are
likely. As secondary low pressure develops offshore (in a Miller B
type evolution), banded structures within the WAA are likely to
translate northward from the Mid-Atlantic into New England, and
then may pivot and drift eastward Sunday night into Monday. Where
this occurs, the heaviest total snowfall accumulations are
probable, reflected by WPC probabilities that are already above 60%
for 12+ inches. While there is some uncertainty into how much=20
mixing will pivot northward, especially from Washington D.C.=20
through Long Island, the interior portions (NW of I-95 and into=20
southern New England which will remain cold as the secondary low=20
develops and tracks near the 40/70 Benchmark) will remain mostly=20
snow with above- climo SLRs leading to significant snowfall=20
accumulations. One other uncertainty that has creeped into the
forecast is a pesky dry slot moving into the Mid-Atlantic and
Northeast Sunday night. This could dry out the mid-level and
drastically cut both precipitation and SLRs. In fact, freezing
drizzle could develop early Monday morning from northern Va to
northern NJ in this scenario before stronger westerly flow picks=20
up on Monday. Many areas are expected to receive more than 12=20
inches from the Ohio Valley through the Mid- Atlantic and into the=20
Northeast before this system winds down in New England on Monday=20
/D4/.

Key Messages for this system are linked below (Key Message 2)


...Great Lakes...=20
Day 1...

Expansive mid-level low centered over the Hudson Bay will begin to
shear open and translate to the east today as a secondary=20
shortwave rotates through its base and atop the Great Lakes this
evening. Behind this impulse, shortwave ridging will amplify=20
across the area, bringing an end to the persistent CAA and=20
associated lake- induced ascent on D1.

The subsequent W/NW flow and accompanying CAA will lead to
impressive lake effect snow (LES) in the favored W/NW snow belts
D1, with some pivoting to more N/NW by early Saturday. The=20
heaviest snowfall is likely east of Lake Ontario D1 where WPC=20
probabilities indicate a moderate risk (50-70%) for at least 8
additional inches in the Tug Hill Plateau. Elsewhere, WPC=20
probabilities suggest a moderate risk (50-70%) for at least 6=20
additional inches across the northeastern U.P.

Additionally, as an arctic cold front pivots into the Northeast,=20
snow squalls along and behind this front are possible. For more=20
details on the snow squall threat in the Northeast through Friday,=20
please refer to our Key Messages (Key Messages 3) below.


Snell/Weiss






...Winter Storm Key Messages are in effect. Please see current=20
Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!6i-JszDvIoz4IkeeFVBNKHjZJfHF0Ybqz-c67ZQcVC-f7= lPz-fsyMDtCovzI6Va6oo9mesLuh66CAbzexuk2Xq7kUJc$=20

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_2.png__;!!DZ3fjg!6i-JszDvIoz4IkeeFVBNKHjZJfHF0Ybqz-c67ZQcVC-f7= lPz-fsyMDtCovzI6Va6oo9mesLuh66CAbzexuk2eCfbSq8$=20

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_3.png__;!!DZ3fjg!6i-JszDvIoz4IkeeFVBNKHjZJfHF0Ybqz-c67ZQcVC-f7= lPz-fsyMDtCovzI6Va6oo9mesLuh66CAbzexuk2Uae-1TY$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 232057
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
357 PM EST Fri Jan 23 2026

Valid 00Z Sat Jan 24 2026 - 00Z Tue Jan 27 2026


...Major winter storm to bring the potential for crippling icing,=20 significant sleet, and heavy snow from the Southern Plains through=20
the Southeast and up the Atlantic Coast into New England...

Meteorological Overview...

A massive winter storm, set to produce a swath of heavy snow and=20
dangerous ice accumulations, has begun today as tropical East=20
Pacific moisture streams out ahead of the 500mb closed low near the
Baja Peninsula. This moisture plume is clashing with the coldest=20
air-mass of the season, entrenching itself over the Nation's=20
Heartland. The moisture transport is exceptional with an
integrated vapor transport (IVT) above the 97.5 climatological=20
percentile per ECMWF SATs. The rich moisture from the south will=20
accompany strong 850-700mb WAA that results in classic over-runing=20
along a developing area of 850-700mb FGEN atop the Southern Plains.
Meanwhile, the upper trough in the Southwest and an emerging=20
upper- level shortwave trough over the Dakotas will strengthen a=20
250mb jet streak over the east-central U.S., placing its thermally-
direct right-entrance region over the Southern Plains. This=20
synoptic- scale setup helps to enhance the mesoscale below,=20
fostering heavy bands of snow and even elevated instability above=20
the low-level sub-freezing layer over north TX on east into the=20
Mid-South tonight and into Saturday.

By Saturday, as the upper low near Baja approaches Texas, its=20
associated jet streak over Mexico will co-locate its divergent=20
left-exit region over the Mid-South and maximize upper-level ascent
over the region. The IVT in advance of the upper trough over=20
Mexico is both expansive and strong with >90th climatological=20
percentile IVT values originating south of Mexico and extending all
the way to the Southern Appalachians by Saturday afternoon. The=20
remarkable extent of the IVT and the slow progression of the Mexico
trough is why parts of the South and Mid-Atlantic are likely to=20
see snow, sleet, and freezing rain for over 24 hours and in some=20
cases approaching 48 hours. As arctic high pressure slides east, a=20
cold-air damming (CAD) signature will become well pronounced along=20
and east of the Appalachians as anomalous Pacific and Gulf moisture
arrives, leading to precipitation falling into the frigid air-mass
and supporting heavy snow, sleet, and freezing rain totals from=20
the southern Appalachians to the Mid-Atlantic.=20

Saturday night and into Sunday is where most changes in the
forecast have unfolded of late. It remains unclear just how strong
the emerging area of low pressure near the Gulf Coast will be and=20
how far north it gets. It is noteworthy that guidance is in good=20
agreement on 700mb Q-vector convergence over northern AL and the=20
southern Appalachians, but the GFS is a little farther south in=20
positioning while the ECMWF is a littler farther north and=20
stronger, resulting in the northern shifts over the last couple=20
days. What they do both agree on is by Sunday, a very pronounced=20
area of strong 700mb Q-vector convergence will unfold along the=20
Mid-Atlantic coast, prompting the development of a coastal low=20
along a strengthening coastal front. With the benefit of the 250mb
jet streak's divergent right-entrance region aloft and the=20
strengthening IVT (ECMWF SATs show >99.5 climatological percentile=20
values over the Southeast Sunday morning), an expansive=20
precipitation shield will span across the OH Valley, Mid-Atlantic,=20
and Northeast with excessive amounts of wintry precipitation=20
falling. While there remains some question on precipitation type,=20
the ECMWF EFI shows the QPF is >0.8 from the Southern Plains and=20
Mid-South to the Northeast, implying an unusually high amount of=20
QPF for this time of year will be at this winter storm's disposal=20
as it falls into a bitterly cold Arctic air-mass.=20

Heavy Snow/Sleet...

The latest forecast calls an astonishingly long swath (over 2,000=20
mile long in length) of >6" of snowfall that starts in the Sangre=20
De Cristo and Sacramento mountains of New Mexico all the way to=20
Downeast Maine. It is worth noting that the snowfall probabilities=20
being referenced will have snow and sleet. Focusing on the Plains=20
first, WPC probabilities sport high chances (>70%) for snowfall >8"
over central OK, southeast KS, southwest MO, and northwest AR.=20
There is another impressive swath of high chance probabilities=20

70%) for >8" of snow from southern IN and north-central KY to=20

eastern Maine. The Central Appalachians, interior Northeast, and=20
southern New England are likely to see the most snowfall with high=20
chances (>70%) for over a foot of snow in these areas. In fact, WPC probabilities show low-to-moderate chances (30-50%) for totals=20
over 18" in the Catskills, Berkshires, and eastern MA. Farther=20
south, the inclusion of sleet from NY and Long Island southward=20
along the I-95 corridor will likely cut into snowfall totals.=20 Climatologically speaking, areas west of I-95 where topography=20
increases are most likely to see more snow than sleet. This is=20
evident in the >8" for snow and sleet probabilities where they are=20
high (>70% chances) from northwest VA and north-central MD along=20
Parrs Ridge to the Lower Susquehanna Valley, but below 50% over=20
southern NJ, the MD eastern shore, and south of Fredericksburg, VA.
Still, the WSO shows >50% chances for a warning-level snowfall as=20
far south as central VA on east through the northern DelMarVa and=20
into southern NJ due to the strong 850-700mb FGEN Saturday night=20
and Sunday morning that fosters snowfall rates that could ranges
between 1-2"/hr. So while snowfall/sleet totals are not quite as=20
high as their neighbors to the north, the combination of snow,=20
sleet, and inclusion of some freezing rain still support=20
significant travel disruptions in these southern areas as well.=20

The WSSI shows widespread Major Impacts (considerable disruptions
to daily life: dangerous to impossible driving conditions,=20
widespread closures, and disruptions to infrastructure) from the TX
Panhandle on east to the Ozarks, through the OH Valley, and all the
way to New England. Every major market along the I-95 metropolitan
corridor (Washington D.C. to Boston and even as far north as
Portland, ME) are expecting major impacts due to snow. The=20
D.C/Baltimore area on north to Philly and NYC are likely to see=20
some inclusion of sleet, but it will still result in significant=20
impacts when accounting for heavy snowfall that is expected to
exceed warning criteria (5-6"). A reminder that bitterly cold=20
temperatures will follow in wake of this storm Monday and into the=20
middle of the week throughout the eastern U.S.. The snow/sleet=20
impacts will linger well into next week with rounds of re-freezing=20
that keeps surfaces icy and dangerous to both drive and walk on for
the foreseeable future. Those in the path of this storm should=20
make final preparations and put plans in place for significant=20
travel disruptions this weekend and into at least early next week.


Freezing Rain:

The most lasting and dangerous impact will come as a result of=20
significant to locally catastrophic ice accumulations due to=20
prolonged periods of freezing rain. Just like the swath of >6" of=20
snowfall, the areal coverage of high chances (>50%) in WPC's ice=20 probabilities exceeding one-quarter inch of ice accumulation is=20
both impressive and alarming. From east-central TX to southern AR,=20
northern LA, northern MS, the TN Valley, northern GA, the southern=20 Appalachians, and southern Mid-Atlantic, these regions are all=20
likely to experience anywhere from one-quarter to one-half inch of=20
ice. Widespread power outages and tree damage is likely in these=20
areas, especially from the Lower MS Valley, southern Appalachians,=20
and central NC where there are also high chances (>70%) for ice=20 accumulations over one-half inch. It is parts of northern AL,=20
northern MS, south-central TN, far northern GA, the southern=20
Appalachians, and the NC Piedmont that are of greatest concern.=20
WPC probabilities show low-to-moderate chances (20-40%) for ice=20 accumulations over 1 inch. These areas are likely to endure a=20
crippling ice storm that will take days, if not weeks, of clean up=20
in addition to extended power outages. Residents in these areas=20
should take final preparations now. Once the freezing rain starts,=20
dangerous travel will be common not only during the event, but in=20
the days in wake of the storm due to prolonged sub-freezing=20
temperatures that cause persistent re-freezing on all untreated=20
surfaces. The Key Messages for the Extreme Cold are linked below
(Key Message 1).

Farther east, freezing rain will reach southern VA, the DelMarVa
Peninsula, and as far north as southern NJ. The southern VA
Piedmont, including the Richmond metro area, have moderate chances
(40-60%) for over one-half inch of ice. The WSSI depicts Major=20
Impacts from Richmond on south along I-95 into NC, while Moderate=20
Impacts (hazardous travel conditions) are anticipated as far north=20
as the northern DelMarVa Peninsula and into the Lower Delaware=20
Valley. While most areas farther north towards the Lower Delaware=20
Valley and southern NJ should largely remain sleet, it may=20
transition to freezing rain for a brief time by Sunday evening. WPC probabilities show low-to-moderate chances (30-50%) for over one-=20
tench of an inch of ice accumulations Sunday evening.


Key Messages for this system are linked below (Key Message 2)


Mullinax



...Winter Storm Key Messages are in effect. Please see current=20
Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!8GUWGIKvjpbH7j06LCzf76dgj7wKmpMcynczXffJXXaY-= mNp6L2dr8o-PiAMPcRJ2YyFHPbCmPdKNKW5sTA1hXXuSxM$=20

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_2.png__;!!DZ3fjg!8GUWGIKvjpbH7j06LCzf76dgj7wKmpMcynczXffJXXaY-= mNp6L2dr8o-PiAMPcRJ2YyFHPbCmPdKNKW5sTA1nTFVkNQ$=20

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_3.png__;!!DZ3fjg!8GUWGIKvjpbH7j06LCzf76dgj7wKmpMcynczXffJXXaY-= mNp6L2dr8o-PiAMPcRJ2YyFHPbCmPdKNKW5sTA1sbzsBKw$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 232103
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
403 PM EST Fri Jan 23 2026

Valid 00Z Sat Jan 24 2026 - 00Z Tue Jan 27 2026


...Major winter storm to bring the potential for crippling icing,=20 significant sleet, and heavy snow from the Southern Plains through=20
the Southeast and up the Atlantic Coast into New England...

Meteorological Overview...

A massive winter storm, set to produce a swath of heavy snow and=20
dangerous ice accumulations, has begun today as tropical East=20
Pacific moisture streams out ahead of the 500mb closed low near the
Baja Peninsula. This moisture plume is clashing with the coldest=20
air-mass of the season, entrenching itself over the Nation's=20
Heartland. The moisture transport is exceptional with an
integrated vapor transport (IVT) above the 97.5 climatological=20
percentile per ECMWF SATs. The rich moisture from the south will=20
accompany strong 850-700mb WAA that results in classic over-runing=20
along a developing area of 850-700mb FGEN atop the Southern Plains.
Meanwhile, the upper trough in the Southwest and an emerging=20
upper- level shortwave trough over the Dakotas will strengthen a=20
250mb jet streak over the east-central U.S., placing its thermally-
direct right-entrance region over the Southern Plains. This=20
synoptic- scale setup helps to enhance the mesoscale below,=20
fostering heavy bands of snow and even elevated instability above=20
the low-level sub-freezing layer over north TX on east into the=20
Mid-South tonight and into Saturday.

By Saturday, as the upper low near Baja approaches Texas, its=20
associated jet streak over Mexico will co-locate its divergent=20
left-exit region over the Mid-South and maximize upper-level ascent
over the region. The IVT in advance of the upper trough over=20
Mexico is both expansive and strong with >90th climatological=20
percentile IVT values originating south of Mexico and extending all
the way to the Southern Appalachians by Saturday afternoon. The=20
remarkable extent of the IVT and the slow progression of the Mexico
trough is why parts of the South and Mid-Atlantic are likely to=20
see snow, sleet, and freezing rain for over 24 hours and in some=20
cases approaching 48 hours. As arctic high pressure slides east, a=20
cold-air damming (CAD) signature will become well pronounced along=20
and east of the Appalachians as anomalous Pacific and Gulf moisture
arrives, leading to precipitation falling into the frigid air-mass
and supporting heavy snow, sleet, and freezing rain totals from=20
the southern Appalachians to the Mid-Atlantic.=20

Saturday night and into Sunday is where most changes in the
forecast have unfolded of late. It remains unclear just how strong
the emerging area of low pressure near the Gulf Coast will be and=20
how far north it gets. It is noteworthy that guidance is in good=20
agreement on 700mb Q-vector convergence over northern AL and the=20
southern Appalachians, but the GFS is a little farther south in=20
positioning while the ECMWF is a littler farther north and=20
stronger, resulting in the northern shifts over the last couple=20
days. What they do both agree on is by Sunday, a very pronounced=20
area of strong 700mb Q-vector convergence will unfold along the=20
Mid-Atlantic coast, prompting the development of a coastal low=20
along a strengthening coastal front. With the benefit of the 250mb
jet streak's divergent right-entrance region aloft and the=20
strengthening IVT (ECMWF SATs show >99.5 climatological percentile=20
values over the Southeast Sunday morning), an expansive=20
precipitation shield will span across the OH Valley, Mid-Atlantic,=20
and Northeast with excessive amounts of wintry precipitation=20
falling. While there remains some question on precipitation type,=20
the ECMWF EFI shows the QPF is >0.8 from the Southern Plains and=20
Mid-South to the Northeast, implying an unusually high amount of=20
QPF for this time of year will be at this winter storm's disposal=20
as it falls into a bitterly cold Arctic air-mass.=20

Heavy Snow/Sleet...

The latest forecast calls an astonishingly long swath (over 2,000=20
mile long in length) of >6" of snowfall that starts in the Sangre=20
De Cristo and Sacramento mountains of New Mexico all the way to=20
Downeast Maine. It is worth noting that the snowfall probabilities=20
being referenced will have snow and sleet. Focusing on the Plains=20
first, WPC probabilities sport high chances (>70%) for snowfall >8"
over central OK, southeast KS, southwest MO, and northwest AR.=20
There is another impressive swath of high chance probabilities=20

70%) for >8" of snow from southern IN and north-central KY to=20

eastern Maine. The Central Appalachians, interior Northeast, and=20
southern New England are likely to see the most snowfall with high=20
chances (>70%) for over a foot of snow in these areas. In fact, WPC probabilities show low-to-moderate chances (30-50%) for totals=20
over 18" in the Catskills, Berkshires, and eastern MA. Farther=20
south, the inclusion of sleet from NY and Long Island southward=20
along the I-95 corridor will likely cut into snowfall totals.=20 Climatologically speaking, areas west of I-95 where topography=20
increases are most likely to see more snow than sleet. This is=20
evident in the >8" for snow and sleet probabilities where they are=20
high (>70% chances) from northwest VA and north-central MD along=20
Parrs Ridge to the Lower Susquehanna Valley, but below 50% over=20
southern NJ, the MD eastern shore, and south of Fredericksburg, VA.
Still, the WSO shows >50% chances for a warning-level snowfall as=20
far south as central VA on east through the northern DelMarVa and=20
into southern NJ due to the strong 850-700mb FGEN Saturday night=20
and Sunday morning that fosters snowfall rates that could ranges
between 1-2"/hr. So while snowfall/sleet totals are not quite as=20
high as their neighbors to the north, the combination of snow,=20
sleet, and inclusion of some freezing rain still support=20
significant travel disruptions in these southern areas as well.=20

The WSSI shows widespread Major Impacts (considerable disruptions
to daily life: dangerous to impossible driving conditions,=20
widespread closures, and disruptions to infrastructure) from the TX
Panhandle on east to the Ozarks, through the OH Valley, and all the
way to New England. Every major market along the I-95 metropolitan
corridor (Washington D.C. to Boston and even as far north as
Portland, ME) are expecting major impacts due to snow. The=20
D.C/Baltimore area on north to Philly and NYC are likely to see=20
some inclusion of sleet, but it will still result in significant=20
impacts when accounting for heavy snowfall that is expected to
exceed warning criteria (5-6"). A reminder that bitterly cold=20
temperatures will follow in wake of this storm Monday and into the=20
middle of the week throughout the eastern U.S.. The snow/sleet=20
impacts will linger well into next week with rounds of re-freezing=20
that keeps surfaces icy and dangerous to both drive and walk on for
the foreseeable future. Those in the path of this storm should=20
make final preparations and put plans in place for significant=20
travel disruptions this weekend and into at least early next week.


Freezing Rain...

The most lasting and dangerous impact will come as a result of=20
significant to locally catastrophic ice accumulations due to=20
prolonged periods of freezing rain. Just like the swath of >6" of=20
snowfall, the areal coverage of high chances (>50%) in WPC's ice=20 probabilities exceeding one-quarter inch of ice accumulation is=20
both impressive and alarming. From east-central TX to southern AR,=20
northern LA, northern MS, the TN Valley, northern GA, the southern=20 Appalachians, and southern Mid-Atlantic, these regions are all=20
likely to experience anywhere from one-quarter to one-half inch of=20
ice. Widespread power outages and tree damage is likely in these=20
areas, especially from the Lower MS Valley, southern Appalachians,=20
and central NC where there are also high chances (>70%) for ice=20 accumulations over one-half inch.=20

It is parts of northern AL, northern MS, south-central TN, far=20
northern GA, the southern Appalachians, and the NC Piedmont that=20
are of greatest concern. WPC probabilities show low-to-moderate=20
chances (20-40%) for ice accumulations over 1 inch. These areas are
likely to endure a crippling ice storm that will take days, if not
weeks, of clean up in addition to extended power outages. This is=20 demonstrated in a rare Extreme Impact on the WSSI in parts of
northern MS, far southern TN, and the Southern Appalachians. The
WSSI Extreme criteria references the potential for "extensive and=20
widespread closures, extremely dangerous travel, and life-saving=20
actions may be needed." Residents in these all referenced regions=20
above should take final preparations now. Once the freezing rain=20
starts, dangerous travel will be common not only during the event,=20
but in the days in wake of the storm due to prolonged sub-freezing=20 temperatures that cause persistent re-freezing on all untreated=20
surfaces. The Key Messages for the Extreme Cold are linked below=20
(Key Message 1).

Farther east, freezing rain will reach southern VA, the DelMarVa
Peninsula, and as far north as southern NJ. The southern VA
Piedmont, including the Richmond metro area, have moderate chances
(40-60%) for over one-half inch of ice. The WSSI depicts Major=20
Impacts from Richmond on south along I-95 into NC, while Moderate=20
Impacts (hazardous travel conditions) are anticipated as far north=20
as the northern DelMarVa Peninsula and into the Lower Delaware=20
Valley. While most areas farther north towards the Lower Delaware=20
Valley and southern NJ should largely remain sleet, it may=20
transition to freezing rain for a brief time by Sunday evening. WPC probabilities show low-to-moderate chances (30-50%) for over one-=20
tench of an inch of ice accumulations Sunday evening.


Key Messages for this system are linked below (Key Message 2)


Mullinax




...Winter Storm Key Messages are in effect. Please see current=20
Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!8yFFARuqbgrlMXfpwPGS4uJRxeJOXQOZNw6H1nZpRTRha= rrS6kEy-awMjMQhdY74aJIFWgelYkKRsYNo7so9y2A1flY$=20

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_2.png__;!!DZ3fjg!8yFFARuqbgrlMXfpwPGS4uJRxeJOXQOZNw6H1nZpRTRha= rrS6kEy-awMjMQhdY74aJIFWgelYkKRsYNo7so9tj5CnIA$=20

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_3.png__;!!DZ3fjg!8yFFARuqbgrlMXfpwPGS4uJRxeJOXQOZNw6H1nZpRTRha= rrS6kEy-awMjMQhdY74aJIFWgelYkKRsYNo7so9VdC50ig$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)