• DAY1 Slight Risk OK/KA/MO

    From Mike Powell@618:250/1 to All on Sat Mar 29 07:54:00 2025
    ACUS01 KWNS 291244
    SWODY1
    SPC AC 291242

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0742 AM CDT Sat Mar 29 2025

    Valid 291300Z - 301200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF CENTRAL/NORTHERN OKLAHOMA INTO SOUTHEAST KANSAS AND MISSOURI...

    ...SUMMARY...
    Scattered severe thunderstorms should occur across parts of the central/southern Plains into the mid Mississippi Valley, mainly this
    evening through the overnight hours. This may include an organized
    thunderstorm cluster across parts of northern Oklahoma into
    southeastern Kansas and western Missouri capable of producing very
    large hail, damaging winds, and perhaps a couple of tornadoes.

    ...Central/Southern Plains into the Mid Mississippi Valley...

    Two mid-level shortwave troughs will impact the central/southern
    Plains today, with the leading low-amplitude perturbation expected
    to move quickly northeastward from the central High Plains to the
    upper MS Valley by this evening. The trailing feature will advance
    from northern Mexico and the Southwest across the southern High
    Plains through the afternoon/evening, eventually reaching the
    Ozarks/mid MO Valley by the end of the period. The primary surface
    low over western KS this morning is forecast to develop
    east-northeastward towards southern IA/northern MO by tonight. An
    attendant cold front will sweep southward across parts of the
    central/southern Plains through the period, while a dryline mixes
    eastward over the southern High Plains this afternoon.

    Low-level moisture is expected to continue streaming northward over
    the central/southern Plains ahead of the cold front and dryline. A
    substantial cap will likely inhibit robust convective development
    until late this afternoon or early evening, with the cold
    front/dryline intersection over western OK a potential location for
    convective initiation by 23-03Z as large-scale ascent with the
    trailing shortwave trough overspreads the warm sector. Moderate to
    strong MUCAPE will likely be present across western/northern OK and
    southern KS, with steep mid-level lapse rates atop upper 50s to mid
    60s surface dewpoints. Sufficiently strong deep-layer shear is also anticipated, which should support supercells initially, with an
    associated threat for large to very large hail (potentially up to
    1.5-2.5 inches in diameter). A brief window may also exist in the
    early to mid evening for a tornado or two with any sustained,
    surface-based supercell, as 0-1 km SRH increases in tandem with a
    strengthening southerly low-level jet. Otherwise, a fairly quick
    transition to a more linear/cluster mode and severe/damaging wind
    threat is expected along or just ahead of the front late this
    evening and overnight, as robust convection spreads northeastward
    across the Ozarks and mid MS Valley before eventually weakening by
    early Sunday morning.

    The severe threat across southern OK into north/central TX ahead of
    the front/dryline appears more conditional, as the better forcing
    aloft will tend to remain farther north. Even so, given an otherwise
    favorable thermodynamic and kinematic environment, large hail and
    damaging winds will likely occur if any thunderstorms can initiate
    and be sustained this evening/overnight. The chance of sustained
    development still appears fairly low given latest guidance trends,
    which supports maintaining the Marginal Risk for the conditional
    severe threat with this update.

    ...Louisiana/Mississippi...

    A remnant MCV will continue to move northeastward today across the
    lower MS Valley and Mid-South. Modestly enhanced low-level southerly
    flow (reference 12Z LCH sounding) should aid in the northward
    transport of additional rich low-level moisture into parts of LA and
    southern MS through the day. While deep-layer shear is expected to
    remain fairly weak, sufficient low-level shear should be present to
    support some updraft organization/rotation. Cells moving
    northeastward and inland over southern LA may pose a threat for a
    brief tornado or two as the boundary layer gradually destabilizes
    with filtered daytime heating. Some guidance also suggests that one
    or more loosely organized clusters may also have a threat for
    isolated damaging winds this afternoon and early evening. Poor lapse
    rates aloft, weak instability, and modest deep-layer shear should
    all act to keep the overall severe threat isolated/marginal.

    ..Gleason/Leitman.. 03/29/2025

    $$
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