ACUS01 KWNS 160611
SWODY1
SPC AC 160609

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0109 AM CDT Thu Apr 16 2026

Valid 161200Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
ACROSS PARTS OF WESTERN AND CENTRAL NEW YORK INTO SOUTHERN
VERMONT...

CORRECTED FOR TYPOS AND WORDING

...SUMMARY...
A few severe thunderstorms are possible this afternoon in a corridor
across western through central New York (state) and adjacent
southern Vermont.

...Discussion...
A significant mid-level trough and embedded low now digging across
the Pacific Northwest is forecast to split as it continues inland
through this period. One perturbation, perhaps including a
continuing cyclonic circulation, is forecast to turn eastward across
the northern Rockies through the central Canadian/U.S. border area.
Another perturbation is forecast to dig southeastward across the
Great Basin into early Friday. It appears that the larger-scale
evolving troughing will be preceded by a significant cold frontal
surge to the lee of the northern U.S. Rockies, through much of the
northern and central Great Plains by 12Z Friday.

Downstream, initially prominent mid-level ridging centered near the
southern Atlantic Seaboard is forecast to become increasingly
suppressed, as one short wave trough, approaching southwestern
portions of the Great Lakes region early today, turns eastward then southeastward across the lower Great Lakes vicinity into northern
Mid Atlantic. It appears that this will be trailed by another
perturbation, which is forecast to progress east of the Ozark
Plateau through the lower Ohio and Tennessee Valleys, before digging
across the southern Appalachians, downstream of short wave ridging
building across and east of the mid/upper Mississippi Valley.

...Mid South into lower Great Lakes and Northeast...
The primary and trailing short wave troughs advancing to the east of
the Mississippi Valley are forecast to be preceded by the remnants
of overnight convection across parts of the lower Great Lakes, Ohio
Valley, and Mid South at the outset of the period. The impacts of
associated cloud cover and outflow on destabilization within the
warm sector of a broad, but weak, surface low migrating northeast of
the lower Great Lakes during the day remain unclear. However,
various model output, including convection allowing guidance,
suggest that destabilization and strengthening shear along a warm
frontal zone (as it strengthens with differential heating) may
become a focus for organized strong thunderstorm development across
New York state by afternoon. It appears that this may include an
evolving cluster, perhaps preceded by more discrete thunderstorm
activity, in an environment conducive to evolving supercell
structures, with potential to produce severe hail, wind and a risk
for a couple of tornadoes.

Additional thunderstorm activity may eventually develop and
strengthen, accompanied by at least a risk for strong to severe wind
gusts by late afternoon, in a corridor of stronger daytime heating
ahead of a developing cold front spreading into the upper Ohio
Valley/Allegheny and Cumberland Plateau.

Farther west/southwest, there is not a well-defined signal in the
latest model output, but a corridor of differential surface heating
along weakening trailing convective outflow across the Mid South
vicinity could become a focus for supercell development. It
currently appears that this potential could peak across north
central into northeastern Arkansas by late this afternoon, aided by
moderate boundary-layer destabilization and stronger mid-level
forcing for ascent associated with a cyclonic vorticity center
migrating across the region.

...Southern Great Plains...
Moderate to strong potential instability is forecast to develop
beneath steep lapse rates, along and east of a dryline which likely
will be retreating westward across the high plains by early this
evening. While this will be conditionally supportive of severe
thunderstorm development, forcing to support initiation of sustained thunderstorms remains unclear, aside from, perhaps, the higher
terrain near/east of the Texas Big Bend. Beneath moderate to strong southwesterly mid/upper flow, this could include an isolated
supercell or two which could propagate across the Rio Grande River,
before weakening in the presence of increasing inhibition this
evening.

..Kerr/Lyons.. 04/16/2026

$$

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ACUS01 KWNS 171705
SWODY1
SPC AC 171703

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
1203 PM CDT Fri Apr 17 2026

Valid 171630Z - 181200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FROM FAR
NORTHWEST OKLAHOMA THROUGH CENTRAL AND EASTERN KANSAS INTO
WEST-CENTRAL MISSOURI...

CORRECTED FOR ORIENTATION OF THE 45% HAIL PROBABILITIES

...SUMMARY...
Numerous severe thunderstorms are likely this afternoon into tonight
across parts of the Upper Midwest southward across the lower
Missouri Valley and central/southern Great Plains. Initially this
may be accompanied by a risk for large to giant hail and a few
strong tornadoes, before severe wind gusts of 60 to 90 mph become
the most prominent hazard by this evening.

...Synopsis...
Recent surface analysis places a low over south-central MN, with a
cold front extending southwestward to another low over central KS. A
warm front also extends southwestward from the MN low through far
southwest MN and far northern IL into central IN. This warm front is
demarcated well by the 56 deg F isodrosotherm. Farther south, a
dryline extends from the triple point KS low back southwestward
through the TX Panhandle and into far southeast NM. A broad, moist
warm sector exists to the east of the cold front and dryline,
characterized largely by dewpoints in the low to mid 60s.

A well-defined shortwave trough is apparent on satellite imagery,
extending from southern Saskatchewan back southwestward into the
eastern Great Basin. This wave is forecast to continue eastward,
with a attendant increase in the mid-level flow across much of the
Plains and Upper/Mid MS Valley. The cold front will surge eastward/southeastward in response to this wave as well, interacting
with the warm sector to support numerous strong to severe
thunderstorms from parts of the Upper Midwest southward across the
lower Missouri Valley into southern Plains.

...Upper/Mid MS Valley...
Moderate to strong low-level moisture advection is expected across
the Upper MS Valley today as the surface low mentioned in the
synopsis progresses northeastward, with an attendant northward shift
of the warm front as well. The risk across this region may evolve in
several phases, beginning with the elevated thunderstorms currently
ongoing across northwest WI. This storms will likely continue
northeastward, posing a risk for severe hail and isolated damaging
gusts. Additional development is possible northwest of this activity
along the occluded front, with some hail possible here as well.

Farther south, the northeastward advecting low-level moisture
coupled with strong heating and steep lapse rates will result in a
strongly unstable airmass along and just south of the warm front by
the early afternoon. Storm initiation is anticipated within this
open warm sector by early afternoon, forced by a mix of warm-air
advection, low-level confluence, and subtly increasing large-scale
ascent. This activity should be ahead of the front and initially
discrete. The overall parameter space will be characterized by
strong to very strong buoyancy, moderate deep-layer vertical shear,
and strong low-level helicity. Supercells capable of all hazards are
expected, including large to very large (i.e. 3"+ hail), strong to
intense tornadoes, and severe wind gusts. Storm interactions are
expected to strongly influence the tornado risk, with the initially
discrete mode likely becoming messy quickly.

Farther west, other storms are likely to evolve quickly along the
front, developing into a band of severe thunderstorms that will push
east coincident with the front. Damaging wind gusts will tend to
become more prevalent during the evening with linear storm modes.
Some tornado risk may continue into the evening as maturing bands of
storms yield a threat for bowing segments and embedded mesovortices,
before this activity gradually diminishes late as it moves east into
IN/Lower MI late.

...KS/OK/MO...
A very unstable airmass is expected to develop along and ahead of
the triple point over south-central KS an associated cold front and
dryline. Strong low-level convergence will likely lead to initial
storm development near the triple point. This initial activity will
be supercellular and capable of very large to giant hail (over
3-3.5" in diameter). Highest coverage of very large hail is expected
over from far northwest OK into south-central KS. Strong downdrafts
(60 to 80 mph) are possible as well. With a largely
boundary-parallel orientation to the deep-layer shear, the tornado
risk appears relatively lower. However, given the supercell mode and
potential interactions with outflow, a low-probability tornado risk
remains. A more north-south configuration to the dryline supports a
conditional tornado risk into far northwest TX.

With time, upscale growth and the development of a
forward-propagating MCS is anticipated across central and eastern
KS. Very strong gusts (80+ mph) are possible with this MCS.
Additionally, some QLCS tornado risk will exist within this line as
long as it stays ahead of the surging cold front. The front will
continue sweeping southeastward, with storms along this boundary
yielding a risk for wind/hail.

..Mosier/Chalmers.. 04/17/2026

$$

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ACUS01 KWNS 261342
SWODY1
SPC AC 261341

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0841 AM CDT Sun Apr 26 2026

Valid 261300Z - 271200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ...

CORRECTED FOR SUMMARY WORDING

...SUMMARY...
Scattered severe thunderstorms with large to very large hail,
damaging winds and tornadoes are expected this afternoon through
tonight across parts of the southern/central Plains. A couple of
strong tornadoes and hailstones up to 2-3 inches in diameter are
possible.

...Southern/Central Plains to the Mid Mississippi Valley...
Fairly substantial changes have been made to the outlook based on
latest observational and guidance trends. Namely, the Enhanced Risk
has been expanded into northern OK to account for the potential of
both surface-based supercells this afternoon, and elevated
supercells this evening/tonight. The Slight Risk has been expanded
southward into north-central TX for a somewhat more
conditional/uncertain supercell threat. The eastern extent of severe probabilities have also been expanded in MO to account for a
potential cluster producing severe/damaging winds occurring late
tonight into early Monday morning.

A weak lead mid-level vorticity maximum over the central High Plains
this morning should continue to aid elevated thunderstorm
development across KS through the afternoon. Increasing MUCAPE with
persistent low-level warm/moist advection and steepening mid-level
lapse rates combined with strong deep-layer shear will support
organized updrafts, including the potential for supercells. This
convection will probably tend to remain elevated to the north of a
front as it spreads east-northeastward over the central Plains, but
scattered large hail may occur given the overall favorable
environment. Isolated 2+ inch diameter hail also appears possible
with the strongest cores. Eventually, this activity may pose a
greater threat for damaging winds across eastern KS into western MO
by late afternoon/early evening, if it can become truly surface
based.

A more notable mid-level shortwave trough is expected to eject
northeastward across the Southwest and southern/central High Plans
today, accompanied by a 50-60 kt southwesterly mid-level jet. Weak
lee cyclogenesis is forecast to occur across the southeast
CO/northeast NM vicinity in response, with the surface low
developing into the OK Panhandle and southwest KS by this evening.
Strong to locally extreme instability is once again forecast to
develop to the east of a sharpening dryline across western/central
OK as daytime heating of a moist airmass occurs. There is still a
fair amount of uncertainty with the placement of an effective warm
front by late afternoon/early evening, but current expectations are
for this boundary to be draped somewhere near north-central OK by
peak afternoon heating. The surface triple point may serve as a
focus for convective initiation today, although better large-scale
ascent associated with the mid-level shortwave trough overspreading
the warm sector will be delayed until this evening and past peak
diurnal heating.

Greater than average uncertainty exists regarding the potential for surface-based convective initiation today in OK/north TX. Still, it
appears possible that multiple supercells may develop with gradual
erosion of lingering MLCIN and weak ascent preceding the ejecting
shortwave trough. Any supercells that can root and ingest the ample
low-level moisture will be capable of producing very large hail
(2-3+ inches in diameter) given a overall rather favorable
environment. The tornado potential is less clear through the day,
but a southerly low-level jet will quickly strengthen this evening
and aid curved/elongated hodographs with strong effective SRH. A
somewhat conditional/uncertain threat for a couple of strong
tornadoes remains apparent, especially if any supercells that can
form this afternoon persist into the evening.

Additional, somewhat elevated supercells may form this evening into
tonight along/north of the warm front from northwest OK near the
triple point into KS. This activity will also pose a threat for
large to very large hail. Some guidance suggests a cluster
eventually evolves from this convection across eastern KS into MO
late tonight/early Monday morning. If this occurs, then a greater
threat for severe/damaging winds would exist.

Farther south into TX, the forcing for ascent will remain
weak/nebulous along the dryline. Still, some potential for a few
supercells is apparent across north-central TX where the greatest
heating and minimal MLCIN is forecast to exist. Large to very large
hail should be the main threat with any splitting supercells that
can develop this afternoon along/east of the dryline and be
sustained.

...ArkLaTex/Lower Mississippi Valley/Central Gulf Coast...
A small cluster will continue tracking southeastward this morning
from southern MS to the central Gulf Coast. With sufficient
low-level moisture and instability in place ahead of this
convection, isolated damaging winds may occur. A pair of supercells
across northeast TX have fluctuated in intensity over the past
couple of hours. The potential for additional thunderstorms to form
on the western flank/outflow of this morning convection remains
unclear given weak large-scale forcing and the low-level jet
forecast to weaken further through the morning. If any additional
convection can form, it would pose an isolated severe hail and
damaging wind threat.

..Gleason/Thompson.. 04/26/2026

$$

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