• MESO: Mesoscale Discussion 0471

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Fri Apr 18 20:52:13 2025
    ACUS11 KWNS 182052
    SWOMCD
    SPC MCD 182051=20
    MIZ000-182245-

    Mesoscale Discussion 0471
    NWS Storm Prediction Center Norman OK
    0351 PM CDT Fri Apr 18 2025

    Areas affected...parts of cntrl and srn Lower Michigan

    Concerning...Severe potential...Watch possible=20

    Valid 182051Z - 182245Z

    Probability of Watch Issuance...40 percent

    SUMMARY...The potential for thunderstorm initiation along and just
    south of a warm frontal zone across lower Michigan is being
    monitored for a possible severe weather watch issuance, as this may
    be accompanied by increasing risk for severe hail and wind by 6-8 PM
    EDT.

    DISCUSSION...A weak perturbation, within larger-scale anticyclonic
    flow on the northwestern periphery of prominent mid-level ridging,
    will continue to progress across and northeast of the middle
    Mississippi Valley through late afternoon. Associated forcing for
    ascent appears to have aided a flare up of convection approaching
    the Greater Milwaukee vicinity, and latest Rapid Refresh suggests
    that this may contribute to erosion of inhibition associated with
    elevated mixed-layer air across southern Lower Michigan by the
    22-00Z time frame.=20=20

    As this occurs, the moistening boundary-layer along and south of a
    warm frontal zone (downstream of a weak surface low migrating across
    southern Wisconsin/northern Illinois) may become characterized by
    CAPE in excess of 1000 J/kg within the next couple hours, in the
    presence of strong deep-layer shear. Although calibrated HREF and
    NCEP SREF guidance indicates highest probabilities for thunderstorm
    development evolving above/to the north of the warm frontal zone,
    initiation of storms closer to and just south of the frontal zone
    will provide the highest potential for organizing and intensifying
    into a severe hail and wind threat.

    ..Kerr/Smith.. 04/18/2025

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!9snil68kA9J5Lb1j1w0r5wfzgvzyi4zpWpC3WFXhuSGNcpP9d4h4hTdJ6t9vX0GoI9rLX3MpD= 93bpqOZpAT6ppdZSQI$ for graphic product...

    ATTN...WFO...DTX...IWX...GRR...

    LAT...LON 43118598 43578274 42438293 41798653 42558615 43118598=20

    MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
    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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