• DAY1 3/5 RISK AREA POSTED

    From Dumas Walker@21:1/175 to All on Thu Feb 19 10:28:40 2026
    ACUS01 KWNS 191302
    SWODY1
    SPC AC 191300

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0700 AM CST Thu Feb 19 2026

    Valid 191300Z - 201200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN
    ILLINOIS AND SOUTHERN INDIANA...

    ...SUMMARY...
    Severe thunderstorms including a few tornadoes, large hail and
    damaging wind gusts are expected across parts of the Midwest and
    lower Ohio Valley today. Elsewhere, storms may produce strong wind
    gusts over parts of coastal south-central California early today.

    ...Midwest/Ohio Valley...
    A strong belt (80-100 kt at 500 mb) of cyclonically influenced
    westerlies will extend from the Southwest Deserts to the Ohio and
    Tennessee Valleys, with modest late-day trough amplification over
    the central Plains and Lower Missouri Valley. A related surface low
    will transition east-northeastward across the Lower Missouri Valley
    toward southern Lake Michigan tonight. A modestly moist warm sector
    will become increasingly established, characterized by mostly 50s F
    surface dewpoints, northward from the Mid-South across most of
    Illinois/Indiana into western/southern Ohio by early evening.

    A steady strengthening of southwesterly winds aloft will occur
    today, increasingly atop/coincident with the modestly moist
    warm-sector boundary layer. Long hodographs will be prevalent with
    upwards of 50-60 kt effective shear by afternoon. Around 200-350
    m2/s2 0-1 km SRH is expected to be maximized on the southeast
    periphery of the surface low and in vicinity of the warm front, with
    the favorable zone including southern Illinois, southern Indiana and
    northern Kentucky.

    Increasing storm development should occur by late morning/midday
    across eastern Missouri, with maturing/increasingly surface-based
    storms near and just north of the I-70 corridor in southern Illinois
    by early afternoon. A semi-focused zone of peak severe/tornado
    potential may unfold generally near I-70, southward to near I-64,
    across southern Illinois and southern Indiana this afternoon through early/mid-evening. Sufficient forcing and boundary layer
    warming/mixing should allow for at least isolated semi-discrete
    development southward into the warm sector, and if so, relatively
    long-lived multi-hour supercells are plausible, with all hazards
    possible, but notably including heightened tornado potential, a few
    of which could be strong (EF2+). Given the limited early season
    moisture, the boundary layer will tend to become more hostile to
    surface-based storms and overall severe potential into mid/late evening.

    ...Coastal South-Central California...
    Bands of shallow convection will continue to move inland this
    morning. Weak destabilization, along with moderate mean
    boundary-layer winds just off the surface, could allow for locally
    strong to damaging gusts as the front progresses southeastward.

    ..Guyer/Grams.. 02/19/2026

    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (21:1/175)
  • From Dumas Walker@21:1/175 to All on Fri Mar 6 11:06:03 2026
    ACUS01 KWNS 061259
    SWODY1
    SPC AC 061258

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0658 AM CST Fri Mar 06 2026

    Valid 061300Z - 071200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
    THE SOUTHERN/CENTRAL PLAINS INTO WESTERN ARKANSAS/MISSOURI AND SOUTHERN IOWA...

    ...SUMMARY...
    Scattered severe thunderstorms are expected from mid afternoon
    through tonight from parts of the southern/central Plains to the
    Ozarks and Midwest. The greatest potential for a few strong
    tornadoes and very large hail should exist across eastern portions
    of Oklahoma/Kansas/Nebraska into western Arkansas/Missouri and southern Iowa.

    ...Synopsis...
    Upper troughing over the western CONUS this morning will evolve into
    more of a split flow pattern through the period, as a lead mid-level
    shortwave trough ejects northeastward across the central
    Plains/Upper Midwest, and a closed low develops over the southern CA
    vicinity. A surface lee cyclone has moved into northwest KS early
    this morning, and is forecast to develop towards IA by this evening,
    while a secondary low shifts eastward along the KS/OK border. A cold
    front attendant to the primary surface low will surge
    east-southeastward across the southern/central Plains and adjacent
    portions of the Midwest through the period, and will likely provide
    a focus for organized severe convection later today. A warm front
    will develop northward through tonight across parts of the Upper
    Midwest/Great Lakes. This boundary should serve as a northern limit
    to the severe threat from surface-based convection. A dryline will
    also extend southward from the secondary surface low across
    western/central OK into TX by late afternoon.

    ...Central Plains into the Midwest/Great Lakes...
    Strong low-level warm/moist advection ahead of the lead mid-level
    shortwave trough will continue to support scattered to numerous
    thunderstorms this morning across eastern KS/NE into northern MO and
    IA/IL. This activity will tend to remain elevated, but could pose an
    isolated hail threat. In the wake of this convection, low-level
    moisture is expected to continue streaming northward today ahead of
    the cold front, with upper 50s to low 60s surface dewpoints common
    by mid afternoon. Cold temperatures aloft and steepened mid-level
    lapse rates will support the development of at least 1000-1500 J/kg
    of MLCAPE with daytime heating. More instability should exist
    farther south into KS where greater low-level moisture will be in place.

    Current expectations are for scattered robust thunderstorms to
    develop around mid afternoon (20-22Z) across southeast NE/northern
    KS and vicinity, in close proximity to the surface low and ejecting
    shortwave trough. Additional convection may also form farther south
    into central/eastern KS. Strong deep-layer shear associated with a
    50-70+ kt mid-level jet will easily support organized updrafts,
    including multiple supercells initially. This activity will pose a
    risk for large to very large hail, but fairly quick upscale growth
    into one or more bowing clusters with a wind damage threat seems
    probable along/ahead of the cold front as convection spreads into
    IA/MO through the evening. Some risk for at least isolated
    severe/damaging winds may persist late tonight into early Saturday
    morning across WI/IL and perhaps even Lower MI if one of these
    clusters can maintain intensity, although instability is forecast to
    become more limited with eastward extent across these areas.

    A few tornadoes may occur with sustained supercells or embedded QLCS circulations across the central Plains/Midwest along/south of the
    warm front given favorable low-level shear and enlarged/curved
    hodographs. A strong tornado appears possible with any supercells
    this evening as low-level shear strengthens in tandem with a south-southwesterly low-level jet. The Enhanced Risk has been
    expanded a little north/westward in northeast KS, southeast NE, and
    southwest IA to account for the very large hail potential with
    initial supercell development. Some consideration was also given to
    greater severe wind probabilities in IA, but confidence in a more
    concentrated corridor of damaging winds is low given the weaker
    instability forecast with eastward extent across the Midwest.

    ...Southern Plains into the Ozarks...
    Convective initiation along the length of the dryline in OK/TX
    remains highly uncertain this afternoon/evening, as low-level
    convergence will be weak and stronger large-scale ascent associated
    with the ejecting shortwave trough will remain mostly displaced to
    the north of these areas. Still, recent HRRR/RAP/NAM guidance
    suggests that MLCIN will be minimal by peak afternoon heating, with
    moderate instability in place along/east of the dryline. If any
    cells can form and be sustained, they would likely become severe and
    pose a threat for very large hail given the presence of steep
    mid-level lapse rates noted on the 12Z OUN observed sounding, along
    with around 35-45 kt of deep-layer shear aiding updraft
    organization. The tornado threat would also increase this evening
    with any persistent supercells as low-level shear gradually
    strengthens. Regardless, the chance for convective initiation still
    appears highly uncertain/conditional this afternoon. A better chance
    for robust thunderstorm development remains apparent later this
    evening/tonight as the cold front advances southward. Both large
    hail and damaging winds may occur with this overnight activity
    through the end of the period.

    Most guidance also continues to show a somewhat separate area of
    thunderstorms developing farther east across eastern OK/western AR
    and vicinity this afternoon into early evening. This activity might
    be aided by a very weak mid-level perturbation moving northeastward
    today across central/northeast TX. If this convection develops, then
    it would pose a threat for all hazards, including large hail,
    damaging winds, and tornadoes (some of which could be strong). No
    changes have been made to the Enhanced Risk across the southern
    Plains/Ozarks with this update.

    ..Gleason/Dean.. 03/06/2026

    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (21:1/175)