• MESO: Mesoscale Discussion 0278

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Fri Mar 28 23:28:31 2025
    ACUS11 KWNS 282324
    SWOMCD
    SPC MCD 282323=20
    WIZ000-MNZ000-290200-

    Mesoscale Discussion 0278
    NWS Storm Prediction Center Norman OK
    0623 PM CDT Fri Mar 28 2025

    Areas affected...Far southeast Minnesota and northern/central
    Wisconsin

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

    Valid 282323Z - 290200Z

    Probability of Watch Issuance...5 percent

    SUMMARY...A couple instances of marginally severe hail (around 1
    inch) are possible through around 03Z.

    DISCUSSION...The latest radar and IR satellite imagery show a
    gradual increase in ascent along/immediately north of a warm front
    draped across portions of central WI -- ahead of a weak surface low
    over southeast MN. This is associated with gradually strengthening
    warm advection in the vicinity of a coupled upper-level jet
    structure. A steep midlevel lapse rate plume extending eastward into
    the area (see earlier 12Z upstream soundings) is contributing to
    around 1000 J/kg MUCAPE, which may increase to around 1500 J/kg as
    ascent moistens the base of the EML. This instability and around
    40-50 kt of cloud-layer shear (per regional VWP data) may promote a
    couple loosely organized supercell structures capable of producing
    hail to around 1 inch in diameter. While the majority of this
    activity is expected to remain elevated, a couple ongoing cells in
    southeast MN into west-central WI are evolving within or slightly on
    the warm side of the baroclinic zone. Even so, isolated severe hail
    should still be the primary hazard.

    The severe-hail risk should generally persist through around 03Z,
    before cellular convection is expected to diminish amid weakening instability/midlevel lapse rates.

    ..Weinman/Mosier.. 03/28/2025

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!_q2uqD1gT-s1rNtgLytvnhD3trKAxLd73BtjUrPb8izNzQ_FfvZKSU0bffUfnvF4orVhAiPr7= db34TWOzUA95onSDQ4$ for graphic product...

    ATTN...WFO...GRB...DLH...ARX...MPX...

    LAT...LON 44018942 43939152 43919237 43989285 44499320 44919312
    45349273 45549210 45589125 45368815 44958768 44458783
    44098819 44018942=20

    MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN


    =3D =3D =3D
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