• DAY1 3/5 Risk Area Posted

    From Mike Powell@618:250/1 to All on Tue Apr 29 08:18:00 2025
    ACUS01 KWNS 291238
    SWODY1
    SPC AC 291237

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0737 AM CDT Tue Apr 29 2025

    Valid 291300Z - 301200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
    WEST TX INTO SOUTHWEST OK...AND FROM THE OH VALLEY INTO THE LOWER
    GREAT LAKES...

    ...SUMMARY...
    Scattered severe thunderstorms are possible within a broad swath
    from the Lower Great Lakes to the southern High Plains, mainly
    during this afternoon to evening. Corridors of greater threat are
    expected over the Upper Ohio Valley/Lower Great Lakes and in parts
    of west Texas into southwest Oklahoma.

    ...Synopsis...
    Recent satellite imagery shows a well-defined shortwave trough
    moving through northwest Ontario and the adjacent Upper Midwest, and
    a mature cyclone centered over the central UT/AZ border. The
    northern shortwave trough is forecast to move eastward across the
    Great Lakes and eastern Canada today while also transitioning to a
    more negative tilt. The UT/AZ cyclone is expected to progress
    southeastward across AZ and into western NM as an embedded shortwave
    trough moves through its base across northern Mexico and into the
    southern High Plains.

    Early morning surface analysis places a low over eastern Lake
    Superior, with a cold front extending southwestward from this low
    into central OK where another, weaker surface low exists. The front
    continues westward from this second low across the TX Panhandle and
    through central NM. The northern low is forecast to progress
    eastward across eastern Canada, moving just ahead of its parent
    shortwave trough, ending the period over the Canadian Maritimes. The
    attendant cold front will also push eastward moving through the OH
    and TN Valleys, and much of the Northeast. Southern/western portion
    of the front will make limited southerly/southeasterly progress,
    with its position becoming more regulated by repeated convective
    outflow throughout the day.

    Numerous thunderstorms, some severe, are anticipated along the
    eastward progressing cold front from the OH Valley into the Lower
    Great Lakes and Northeast, as well as farther southwest across the
    southern Plains near the stalled boundary.

    ...Ohio Valley into the Lower Great Lakes...
    Ongoing cluster across northeast OK will continue through the Ozarks
    this morning before reaching the Lower OH Valley this afternoon. It
    seems probable that this cluster will reintensify as it interacts
    with the destabilizing airmass over the region. Additional
    thunderstorm development appears likely along the front north of
    this cluster throughout much of the OH Valley into the Lower Great Lakes.

    Strong low/midlevel flow will support development of organized storm
    clusters, along with some potential for discrete or embedded
    supercells. Scattered damaging winds will be possible, with some
    potential for swaths of more concentrated wind damage if any
    organized linear segments develop. The strongest low-level flow will
    be displaced north of the region, but 35-50 kt in the 850-700 mb
    layer will support sufficient low-level shear for some supercell
    and/or line-embedded tornado threat. Isolated hail could also
    accompany any persistent supercell structures.

    ...West TX into the Ozarks...
    Complex convective evolution is underway across OK this morning as a northeastward progressing convective cluster interacts with the
    thunderstorms that developed along the front over
    northwest/north-central OK. Current trends and recent guidance
    suggest that an MCS will evolve and then track northeastward across
    the Ozarks. The airmass downstream is expected to remain supportive
    of damaging gusts and large hail for at least the next few hours.

    Another round of thunderstorms is anticipated this afternoon both
    along the outflow-modulated cold front in OK and northwest TX and
    along the dryline in West TX as the airmass destabilizes. Strong
    buoyancy and shear will support supercells, particularly from west
    TX into southwest OK during the late afternoon where low-level
    convergence will be strongest. Large to very large hail will be the
    primary threat initially, but strong cold pools and close storm
    proximity should result in several clusters capable of strong to
    significant gusts. A mesoscale corridor of greater tornado potential
    may materialize just east of the surface low where stronger
    southeasterly low-level flow and higher low-level moisture may
    overlap. Current guidance suggests this would be over northwest TX,
    but uncertainty exists regarding the outflow/cold front and surface
    low positions, precluding the confidence needed to outlook higher
    tornado probabilities.

    ..Mosier/Jewell.. 04/29/2025

    $$
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  • From Mike Powell@618:250/1 to All on Fri May 2 09:00:00 2025
    ACUS01 KWNS 021258
    SWODY1
    SPC AC 021257

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0757 AM CDT Fri May 02 2025

    Valid 021300Z - 031200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM
    CENTRAL/EAST TEXAS TO THE LOWER MISSISSIPPI VALLEY AND TENNESSEE
    VALLEY...

    ...SUMMARY...
    Widespread strong thunderstorm development is expected from parts of
    central and eastern Texas to the lower Mississippi and Tennessee
    Valleys, and into the Cumberland Plateau by evening. This includes
    potential for large hail and damaging wind gusts.

    ...Southern Plains to Lower Mississippi Valley/Tennessee Valley...
    A residual MCS, with diminished intensity since early on the
    overnight, persists at daybreak along the Red River and
    Texas/Oklahoma border region eastward into the Mid-South largely
    paralleling I-40, with a probable related MCV across eastern
    Oklahoma. A relatively isolated severe potential will initially
    exist with these storms this morning. However, an intensification of related/downstream storms is expected by midday, potentially
    spanning parts of Arkansas into western/Middle Tennessee, western
    Kentucky, and northern Alabama. Additional severe storm development
    will be possible this afternoon northeastward into the middle Ohio
    Valley and toward the Cumberland Plateau, as increasing
    low-level/deep-layer southwesterly winds overlie a moderately
    unstable boundary layer. Multiple organizing storm clusters can be
    expected regionally this afternoon into evening.

    Farther southwest across central/eastern Texas, while considerable
    drying and stabilization is still apparent in observational data
    after last evening's MCS, the air mass should steadily recover with
    moistening and relatively aggressive destabilization into peak
    heating. Initial thunderstorm development will be accompanied by the
    potential for large hail, with supercells capable of very large hail
    possible especially with west-southwestward extent into the Edwards
    Plateau and toward the Rio Grande. Damaging wind potential will also
    increase as convection organizes and spreads southeastward into this
    evening across central/southeast Texas, and possibly Deep South
    Texas tonight.

    ..Guyer/Jewell.. 05/02/2025

    $$
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