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  • MESO: Mesoscale Discussion 1663

    From COD Weather Processor @1:2320/107 to All on Sun Jul 19 20:56:30 2026
    ACUS11 KWNS 192056
    SWOMCD
    SPC MCD 192055
    NDZ000-SDZ000-192300-

    Mesoscale Discussion 1663
    NWS Storm Prediction Center Norman OK
    0355 PM CDT Sun Jul 19 2026

    Areas affected...portions of southern North Dakota into northern
    South Dakota

    Concerning...Severe potential...Severe Thunderstorm Watch likely

    Valid 192055Z - 192300Z

    Probability of Watch Issuance...80 percent

    SUMMARY...Developing, high-based convection will evolve eastward
    through this evening, bringing a risk for severe wind gusts (some
    potentially significant) and large hail, perhaps to 2-3+ inches in
    diameter.

    DISCUSSION...A developing cumulus field across far southwestern
    ND/northwestern SD has shown some signs of increased vertical growth
    over the past hour, with isolated thunderstorms noted across Perkins
    and Meade Counties in South Dakota as of 2050 UTC. Additional
    development is expected amid continued insolation and along a southeastward-progressing cold front over the next couple of hours.
    A modified 18z BIS sounding indicates steep low- and mid-level lapse
    rates are in place across this region along with around 30 kts of
    effective shear and relatively straight, elongated hodographs.
    Coupled with strengthening upper-level flow and further hodograph
    elongation with time, this environment will be supportive of
    initial, high-based splitting supercells capable of large hail
    (potentially to 2-3+ inches in diameter) and severe outflow wind
    gusts to 80+ mph. Efficient evaporative cooling will favor cold pool development, with upscale growth into one or more clusters (and a
    transition towards severe wind gusts as the primary threat) then
    expected as convection spreads eastward with time. A Severe
    Thunderstorm Watch will likely be needed later this afternoon to
    cover this severe potential.

    ..Chalmers/Thompson.. 07/19/2026

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fjg!-bVIuaqcq1dXEAvb7VbcYdgoER4xN7wrsxLO8iSUqmmnGIIz0Qb-nqQi9JEhb-15M-qmU62u7HFLJmz9mVZj77wB21Q$ for graphic product...

    ATTN...WFO...FGF...ABR...BIS...UNR...

    LAT...LON 46600306 47240277 47560236 47740141 47750043 47659973
    47419909 47049869 46319820 45639824 45119891 44899991
    44790092 44800171 45010249 45300275 45970300 46600306

    MOST PROBABLE PEAK WIND GUST...75-90 MPH
    MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN


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    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)