• MESO: Mesoscale Discussion 0466

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Fri Apr 18 10:06:09 2025
    ACUS11 KWNS 181006
    SWOMCD
    SPC MCD 181005=20
    WIZ000-ILZ000-IAZ000-181230-

    Mesoscale Discussion 0466
    NWS Storm Prediction Center Norman OK
    0505 AM CDT Fri Apr 18 2025

    Areas affected...Northeast Iowa...Southern Wisconsin

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

    Valid 181005Z - 181230Z

    Probability of Watch Issuance...20 percent

    SUMMARY...An isolated threat for large hail and severe gusts will
    likely continue across parts of northeast Iowa over the next few
    hours. The threat is also expected to affect parts of southern
    Wisconsin. Weather watch issuance is unlikely.

    DISCUSSION...The latest high-resolution radar imagery from Des
    Moines shows a cluster of thunderstorms across northeast Iowa and
    far southwest Wisconsin. Some of these storms have produced severe
    reports over the last couple of hours. The cluster will continue to
    move eastward into southern Wisconsin this morning. RAP forecast
    soundings from northeast Iowa into southern Wisconsin have a
    temperature inversion up to about 850 mb. Across northeast Iowa,
    MUCAPE is estimated by the RAP in the 1000 to 2000 J/kg range.
    Instability further to the east is considerably less, but an
    increase in instability could still occur as warm advection
    continues through the morning. In addition, RAP analysis across
    northeast Iowa has effective shear generally in the 40 to 50 knot
    range. This environment should support elevated supercells capable
    of producing isolated large hail. In spite of the low-level
    temperature inversion, a strong to severe gust will also be
    possible. The severe threat should develop eastward across southern
    Wisconsin but may become more isolated as the storms outrun the
    instability further to the west.

    ..Broyles/Gleason.. 04/18/2025

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!7Bl8SJgEoCzbTyNBKwcQfc3eqUDfrlEYjwaG_9UIkjf4HmPvR3IAJSFj7m913188eYlXk0i0-= oG_eAlOJvraC_l4uCE$ for graphic product...

    ATTN...WFO...LOT...MKX...DVN...ARX...DMX...

    LAT...LON 42458882 42479059 42539253 42669327 43109340 43499266
    43488999 43368824 42768793 42508828 42458882=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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