• MESO: Mesoscale Discussion 1889

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Tue Aug 5 07:59:15 2025
    ACUS11 KWNS 050759
    SWOMCD
    SPC MCD 050758=20
    SDZ000-MTZ000-WYZ000-050930-

    Mesoscale Discussion 1889
    NWS Storm Prediction Center Norman OK
    0258 AM CDT Tue Aug 05 2025

    Areas affected...far southeast Montana...far northeast Wyoming and
    western South Dakota.

    Concerning...Severe potential...Watch unlikely=20

    Valid 050758Z - 050930Z

    Probability of Watch Issuance...20 percent

    SUMMARY...Isolated large hail is possible early this morning across
    portions of southeast Montana, northeast Wyoming, and western South
    Dakota.

    DISCUSSION...The low-level jet has strengthened significantly over
    the past hour across western South Dakota (now approaching 40 knots
    on the KUDX VWP). As a result, elevated thunderstorms have increased
    in coverage across western South Dakota and far southeast Montana.
    An environment featuring 30 to 40 knots of deep layer shear, 2000 to
    2500 J/kg MUCAPE, and support from the low-level jet may result in a
    few elevated supercells capable of primarily large hail early this
    morning. In addition, a mature MCS has developed across southeast
    Montana. As this MCS advances east, at least some severe wind
    potential could exist if a more consolidated/faster moving segment
    can emerge from this MCS. At this time, the stronger storm in Powder
    River, Montana would likely have the greatest potential for this
    solution as it moves east-southeast along the instability gradient
    early this morning. Given the isolated nature of the threat, a
    severe thunderstorm watch is unlikely.

    ..Bentley/Mosier.. 08/05/2025

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!8xe_eOjjx-okUWN7N6wNUvhPCKtiQF87ee2kiX1tAXqsFQAuS8LuMEWl8VC6JLQD52407E_n4= PruecWZFn4p7DDWxTE$ for graphic product...

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

    LAT...LON 44850523 45120566 45320572 45520561 45690440 45650320
    45280185 44810143 44080122 43310115 43000191 43020270
    43150354 44010408 44590467 44850523=20

    MOST PROBABLE PEAK WIND GUST...55-70 MPH
    MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN


    =3D =3D =3D
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