• MESO: Mesoscale Discussion 1440

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Wed Jun 25 21:22:17 2025
    ACUS11 KWNS 252122
    SWOMCD
    SPC MCD 252121=20
    SDZ000-NDZ000-MTZ000-WYZ000-252245-

    Mesoscale Discussion 1440
    NWS Storm Prediction Center Norman OK
    0421 PM CDT Wed Jun 25 2025

    Areas affected...portions of eastern Montana into northeast Wyoming
    and western South Dakota

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

    Valid 252121Z - 252245Z

    Probability of Watch Issuance...20 percent

    SUMMARY...A few instances of severe hail or wind may accompany the
    stronger multicell or supercell structures over the next several
    hours. However, the overall severe threat should remain isolated.

    DISCUSSION...Multiple multicells and supercells have developed and
    intensified over the last few hours given the combination of
    low-level upslope flow and diurnal heating. Surface temperatures are
    in the 70s F amid 50 F surface dewpoints over the higher terrain, to
    low 60s F dewpoints farther to the east into western SD. This
    moisture, overspread by 7-8 C/km mid-level lapse rates, yields
    1000-1500 J/kg MLCAPE amid 40 kts of effective bulk shear.
    Hodographs, evident via 21Z mesoanalysis, are mainly straight and
    elongated, suggesting that multicells and splitting supercells
    should remain the primary modes of convection. Severe wind and hail
    will be the main convective hazards, though the overall modest
    buoyancy/shear parameter space and forcing for ascent suggests that
    the severe threat should be isolated.

    ..Squitieri/Guyer.. 06/25/2025

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!5XCJN-pjZvbJhRrV1yRMIIn2pG5KrwkvqKzXXXacozAThXjKEJf9OrgEqLIaChEPhQDV88WGc= m9Us7e57JAP9Tk77Hc$ for graphic product...

    ATTN...WFO...ABR...BIS...UNR...CYS...BYZ...GGW...RIW...

    LAT...LON 44030610 45990647 47710687 48200624 48120518 47040296
    45370156 43960083 43460091 43160154 43020229 43160350
    43550467 44030610=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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