• MESO: Severe Thunderstorm

    From Weather Alert@454:1/105 to All on Wed Jan 19 16:53:00 2022
    ACUS11 KWNS 192100
    SWOMCD
    SPC MCD 192100
    MSZ000-LAZ000-ARZ000-192300-

    Mesoscale Discussion 0087
    NWS Storm Prediction Center Norman OK
    0300 PM CST Wed Jan 19 2022

    Areas affected...Parts of northeastern Louisiana...southeastern
    Arkansas...west central Mississippi

    Concerning...Severe Thunderstorm Watch 16...17...

    Valid 192100Z - 192300Z

    The severe weather threat for Severe Thunderstorm Watch 16, 17
    continues.

    SUMMARY...The risk for potentially damaging wind gusts may gradually
    increase with an evolving cluster or line of storms through 5-7 PM
    CST.

    DISCUSSION...Within the narrow corridor of deeper, boundary-layer
    based moisture return, thunderstorms have begun to consolidate in an
    area centered near the Louisiana/Arkansas border. This is where
    mid-level temperatures are a bit cooler, and forcing for ascent
    associated with a low-amplitude short wave trough emerging from the
    southern Great Plains is stronger, compared to areas farther south,
    near the Gulf coast. Further upscale growth seems probable during
    the next few hours, as the low-level moist axis gradually shifts
    eastward across the lower Mississippi Valley, coincident with the
    progression of the mid-level impulse.

    While latest model output suggests that flow around 850 mb will
    continue to gradually weaken and veer in advance of a southward
    progressing cold front, there may be some strengthening of
    west-southwesterly flow to 30-40 kt as low as the 700 mb level.
    With colder surface air just now gradually spreading through the
    I-40 corridor of central Arkansas, it appears unlikely that
    convection will be undercut by the cold front anytime soon. As a
    result, there appears a window of opportunity for an upscale growing
    cluster or line of storms to generate a cold pool, perhaps gradually
    posing increasing potential to produce potentially damaging surface
    gusts.

    Near or just ahead of the developing convective system, while modest
    to weak low-level flow will limit hodograph size, model forecast
    soundings do exhibit substantive clockwise curvature. An isolated
    tornado or two may not be entirely out of the question, particularly
    with any sustained discrete storm development.

    ..Kerr.. 01/19/2022

    ATTN...WFO...MEG...JAN...SHV...

    LAT...LON 32599222 33269130 34139051 33498933 31599184 32119290
    32599222
    $$
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  • From Weather Alert@454:1/105 to All on Wed Jun 22 18:22:00 2022
    ACUS11 KWNS 222217
    SWOMCD
    SPC MCD 222216
    PAZ000-VAZ000-MDZ000-DCZ000-WVZ000-230015-

    Mesoscale Discussion 1260
    NWS Storm Prediction Center Norman OK
    0516 PM CDT Wed Jun 22 2022

    Areas affected...Central and Southern Pennsylvania...Eastern West Virginia...Western Maryland...Central and Eastern Virginia

    Concerning...Severe Thunderstorm Watch 400...401...

    Valid 222216Z - 230015Z

    The severe weather threat for Severe Thunderstorm Watch 400, 401
    continues.

    SUMMARY...Convective coverage is expected to increase across parts
    of WW 400 and WW 401 over the next couple of hours. In response, the
    potential for wind damage and hail will likely continue.

    DISCUSSION...Latest mosaic radar imagery from Pennsylvania southward
    into Virginia show a few clusters of strong to severe thunderstorms.
    The first is in north-central Pennsylvania and the second in
    southwestern Pennsylvania. These two clusters are located along and
    near an axis of strong instability, with the RAP analyzing MLCAPE in
    the 3000 to 3500 J/kg range. As the two clusters approach each
    other, linear development will be possible. This convection will
    move southeastward into the northwestern part of WW 400. Wind damage
    and hail will be possible with the stronger cells.

    Further south into northern Virginia, a third cluster is ongoing
    near an axis of weak instability. The airmass immediately to the
    south appears to have been undisturbed. This will make a severe
    threat possible early this evening. The RAP has 0-3 km lapse rates
    in the 7.5 to 8.0 C/km range across parts of south-central Virginia,
    suggesting a wind-damage threat will be possible with the stronger
    multicells within the cluster.

    ..Broyles.. 06/22/2022

    ATTN...WFO...AKQ...CTP...LWX...RNK...

    LAT...LON 41467733 41557796 41417839 41067864 40407886 39917926
    39487933 39127923 38247913 37967908 37017891 36757851
    36697825 36717763 36907728 37367692 38057689 39127689
    41077693 41467733


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