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  • MESO: Mesoscale Discussion 1617

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Wed Jul 9 18:34:12 2025
    ACUS11 KWNS 091832
    SWOMCD
    SPC MCD 091831=20
    SDZ000-MTZ000-WYZ000-092030-

    Mesoscale Discussion 1617
    NWS Storm Prediction Center Norman OK
    0131 PM CDT Wed Jul 09 2025

    Areas affected...portions of western into central South Dakota

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

    Valid 091831Z - 092030Z

    Probability of Watch Issuance...80 percent

    SUMMARY...Scattered thunderstorm development appears imminent.
    Storms should gradually intensify through the afternoon, accompanied
    by a severe wind and hail threat. A Severe Thunderstorm Watch
    issuance will be needed in the next few hours.

    DISCUSSION...Visible satellite shows deepening CU along the Black
    Hills in southwestern SD, where convective inhibition continues to
    rapidly erode with boundary-layer heating/mixing. MLCAPE is already
    reaching the 1500-2500 J/kg range ahead of the storms, with over 30
    kts of effective bulk effective shear (and a straight hodograph)
    already in place (per 18Z mesoanalysis/UNR special observed
    sounding). Thunderstorms should develop shortly, and will soon after
    move over the more unstable/sheared airmass. Current thinking is
    that storms should remain more discrete for a few hours before
    attempting to grow upscale. Given steep low-level lapse rates,
    severe gusts are a concern (a few of which may exceed 75 mph), with
    the 8-9 C/km 700-500 mb lapse rates and straight hodographs
    supporting severe hail potential as well. A Severe Thunderstorm
    Watch will eventually be needed to address the increasing severe
    threat.

    ..Squitieri/Mosier.. 07/09/2025

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!9DOQTPnivZrFCyEBEYf4FocOZ-e86ABSgnR2ig-wxmER1v-MNgPuP2mzaW9ItMgWgV3Jenzco= IP9yI1YKW99eVJD26c$ for graphic product...

    ATTN...WFO...ABR...UNR...BYZ...

    LAT...LON 43080277 43930359 45510441 45770433 45870371 45640180
    45120043 44360004 43700015 43270086 43000202 43080277=20

    MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
    MOST PROBABLE PEAK WIND GUST...65-80 MPH
    MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN


    =3D =3D =3D
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