• MESO: Mesoscale Discussion 0569

    From COD Weather Processor@1:2320/107 to wx-storm@lists.illinois.edu on Mon Apr 27 17:52:41 2026
    ACUS11 KWNS 271752
    SWOMCD
    SPC MCD 271752=20
    WIZ000-IAZ000-MNZ000-272015-

    Mesoscale Discussion 0569
    NWS Storm Prediction Center Norman OK
    1252 PM CDT Mon Apr 27 2026

    Areas affected...southeast Minnesota...northeast Iowa...and
    southwest Wisconsin

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

    Valid 271752Z - 272015Z

    Probability of Watch Issuance...20 percent

    SUMMARY...Isolated severe storms are possible this afternoon with
    the primary hazard being hail up to 1.0-1.5" in diameter.

    DISCUSSION...Early-afternoon water-vapor imagery indicates a
    vigorous vorticity maximum over northern IA into southern MN,
    lifting to northeast. At the surface, 17z analysis placed a low over south-central MN with a cold front trailing to the south-southwest,
    and a trough/wind shift extending southeast into eastern IA.

    Convection is in the process of deepening as of 17z along the cold
    front in north-central IA amidst a marginally unstable air mass with
    estimated MLCAPE of 250-500 J/kg, per objective analysis. Breaks in
    the clouds ahead of the cold front will allow for further
    destabilization this afternoon, especially given the height
    falls/mid-level cooling overspreading the region from the
    west/southwest. As such a few strong to potentially severe storms
    are expected to develop along and ahead of the surface low and cold
    front this afternoon with the primary hazard being hail up to
    1.0-1.5" in diameter.=20

    Veered low-level winds (evident in RAP forecast soundings) are
    expected to limit a more robust tornado threat, at least along the
    cold front. A potentially more favorable low-level wind profile
    likely exists along/east of the surface wind shift preceding the
    cold front. The most likely location for a brief spin up is along
    and to the southeast of the surface low track where local maximum in
    surface vorticity will coincide with 0-3-km CAPE of 100-125 J/kg.

    ..Mead/Guyer.. 04/27/2026

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!6I47VfsAZVtV6ec2zjdhn0PuQEain3EIrgjL5Lxaho5WKbC2yZZdp5VS4vx_5CPEe-D3pzyI0= jtEtnOnrQzqTVd9QjY$ for graphic product...

    ATTN...WFO...MKX...DVN...ARX...MPX...DMX...

    LAT...LON 43249360 44199277 44519158 44128998 42799001 42249125
    42079218 42519343 43249360=20

    MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
    MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
    MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN


    =3D =3D =3D
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