• DAY1 3/5 Risk Area Posted UPDATED

    From Mike Powell@618:250/6 to All on Wed Apr 29 20:18:02 2026
    ACUS01 KWNS 292002
    SWODY1
    SPC AC 292000

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0300 PM CDT Wed Apr 29 2026

    Valid 292000Z - 301200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
    THE EDWARDS PLATEAU INTO SOUTH-CENTRAL TEXAS...

    ...SUMMARY...
    Severe thunderstorms are forecast from parts of Texas to the Gulf
    Coast states today. Scattered large to very large hail and damaging
    winds are the primary risks, with giant hail possible in parts of
    south-central Texas.

    ...20Z Update...
    The primary change with this update was the addition of an Enhanced
    Risk for portions of the Edwards Plateau into south-central TX --
    driven by a CIG2 (intensity level 2/2) hail area. The latest visible
    satellite imagery indicates an agitated boundary-layer cumulus field
    evolving east of Fort Stockton in Crockett County, where attempts at
    isolated convective initiation are underway. Current thinking is
    that continued diurnal heating of a moist air mass (lower 70s
    dewpoints) and upslope flow enhancements will result in isolated to
    widely scattered thunderstorms this afternoon into the evening.
    Current thinking is that storms will track/develop southeastward
    into a corridor of strong to extreme buoyancy -- driven by steep
    midlevel lapse rates (around 8.5 C/km per 12Z DRT sounding) atop the destabilizing PBL. This, combined with a long/straight hodograph
    (60-70 kt of effective shear) and modest forcing for ascent will
    favor intense discrete/splitting supercells. Given the modest
    forcing for ascent, it is unclear how many storms will form in this
    corridor, though any sustained supercells will pose a risk of very
    large to giant hail (3-4+ inches in diameter).

    ..Weinman.. 04/29/2026

    .PREV DISCUSSION... /ISSUED 1049 AM CDT Wed Apr 29 2026/

    ...Texas into the Lower Mississippi Valley/Southeast...

    Satellite imagery late this morning indicates high momentum
    quasi-zonal flow from TX eastward across the central Gulf Coast. An
    upstream perturbation over Chihuahua is forecast to move quickly
    east today reaching central TX late this afternoon. Isolated to
    scattered thunderstorms are forecast to increase in
    coverage/intensity mainly along/near a surface front draped from
    west-central TX to southern AR. A moisture-rich airmass featuring
    lower 70s deg F surface dewpoints south of the front, coupled with a
    plume of 8 deg C/km 700-500 mb lapse rates and some diurnal heating,
    will contribute to 2000-4000 J/kg of MLCAPE decreasing with east extent.

    A few initial thunderstorms clusters north of the surface front over
    TX are expected to gradually intensify through early afternoon. The
    moderate to very unstable airmass will combine with elongated/nearly
    straight hodographs to support supercell development with the
    stronger updrafts and an associated risk for large to very large
    hail (1 to 3 inches in diameter). Have extended the 15-percent hail
    and CIG1 hail delineation farther east into northeast TX and western
    LA. For short-term forecast details, please refer to MCD #615.
    Eventually upscale growth into one or more clusters is expected to
    evolve across LA into the central Gulf Coast states later this
    afternoon. Damaging gusts and an isolated risk for large hail will
    be the primary hazards with the stronger storms.

    Farther west, isolated to widely scattered intense storm development
    is forecast across the Edwards Plateau this afternoon. This
    activity may eventually focus closer to the Rio Grande later this
    evening with a large to very large hail threat persisting well after dark.

    ...Upper OH Valley into the Mid-Atlantic/North Carolina...

    Within large-scale upper troughing over the Great Lakes/Midwest, an
    embedded mid-level shortwave trough will move northeastward across
    the Mid-Atlantic this afternoon/evening in tandem with an
    eastward-moving surface cold front. Only modest boundary layer
    moisture is present across the region, with surface dewpoints
    generally in the 50s. Forecast soundings over western PA show some
    low-level hodograph curvature within a moist environment. Main
    uncertainty across the upper OH Valley is the magnitude of
    destabilization in this area given ongoing scattered showers and
    widespread cloud cover. Nonetheless, a couple of stronger storms
    could yield an isolated risk for wind damage and perhaps a brief
    tornado later this afternoon, especially near/southeast of a weak
    surface low. Farther south, isolated wind/hail will be possible
    with the stronger thunderstorms through the late afternoon/early evening.

    $$


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