• MESO: Mesoscale Discussion 1999

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Tue Aug 15 17:29:06 2023
    ACUS11 KWNS 151729
    SWOMCD
    SPC MCD 151728=20
    NJZ000-PAZ000-MDZ000-DEZ000-VAZ000-NCZ000-DCZ000-152000-

    Mesoscale Discussion 1999
    NWS Storm Prediction Center Norman OK
    1228 PM CDT Tue Aug 15 2023

    Areas affected...Portions of NC into the Mid-Atlantic

    Concerning...Severe potential...Severe Thunderstorm Watch likely=20

    Valid 151728Z - 152000Z

    Probability of Watch Issuance...80 percent

    SUMMARY...The threat for scattered damaging winds and isolated hail
    should increase this afternoon. One or more Severe Thunderstorm
    Watches will likely be needed as thunderstorms develop.

    DISCUSSION...An upper trough/low centered over the Great Lakes/OH
    Valley will continue moving slowly eastward this afternoon. Modest
    ascent preceding this feature and low-level convergence along a
    surface cold front will likely foster robust convective initiation
    within the next 1-2 hours (by around 3 PM EDT) across parts of
    western/central NC into the coastal Mid-Atlantic. Strong daytime
    heating has already warmed surface temperatures into the upper 80s
    and 90s across this region. A rather moist airmass, with
    precipitable water values of 1.5 to 2+ inches and surface dewpoints
    generally in the 70s, should help offset poor mid-level lapse rates
    to some extent. Around 1500-3000+ J/kg of MLCAPE has already
    developed given the ample diurnal heating that has occurred.

    While weak west-southwesterly low-level winds exist, they do
    strengthen with height to around 45-60 kt through mid levels.
    Related 35-50 kt of deep-layer shear will act to organize updrafts,
    with a mix of bowing clusters and supercells possible. Isolated
    severe hail may occur with the more discrete convection that
    initially develops. A tendency for upscale growth into multiple
    clusters appears likely given the linear forcing of the front and
    mainly boundary-parallel flow aloft. Scattered damaging/severe wind
    gusts should be the main threat as this convection spreads eastward
    through the rest of the afternoon and evening. One or more Severe
    Thunderstorm Watches will likely be needed as robust convection
    develops over the next couple of hours.

    ..Gleason/Hart.. 08/15/2023

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!4rXFvoL8EytGEovS3bl48n3EAdobrEmR568i0RajsWJD9gC9TVcaI4rstMzuYYO8yXRYprDsU= QLVrx98jkDvWc_AYNE$ for graphic product...

    ATTN...WFO...PHI...AKQ...CTP...LWX...RAH...RNK...GSP...

    LAT...LON 35918159 37517862 39257730 39697670 39997571 39737451
    39277435 37747544 36387708 35227845 35017985 35318153
    35918159=20


    =3D =3D =3D
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