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  • MESO: Mesoscale Discussion 0760

    From COD Weather Processor@1:2320/107 to wx-storm@lists.illinois.edu on Sun May 17 22:46:12 2026
    ACUS11 KWNS 172246
    SWOMCD
    SPC MCD 172245=20
    MNZ000-IAZ000-172345-

    Mesoscale Discussion 0760
    NWS Storm Prediction Center Norman OK
    0545 PM CDT Sun May 17 2026

    Areas affected...portions of northern Iowa into southern Minnesota

    Concerning...Severe potential...Tornado Watch likely=20

    Valid 172245Z - 172345Z

    Probability of Watch Issuance...80 percent

    SUMMARY...The severe threat will increase over the next few hours.
    Severe wind and hail are likely, with tornadoes also possible. A
    Tornado Watch may be needed soon to address the impending threat.

    DISCUSSION...A bowing QLCS is traversing the far western IA/MN
    border, with a recent history of marginal severe hail/wind occurring
    with an embedded supercell structure. This QLCS is tracking eastward
    toward the axis of a 30-40 kt low-level jet, where low-level shear
    is increasing (i.e. 200+ m2/s2 effective SRH per 22Z mesoanalysis). Furthermore, 8+ C/km mid-level lapse rates are overspreading upper
    60s to near 70 F surface dewpoints in the warm sector ahead of the
    QLCS, yielding up to 3000 J/kg MLCAPE. With 40+ kts of effective
    bulk shear also in place, potential exists for the QLCS to
    strengthen, with a corresponding increase in severe wind and hail
    potential. Line-embedded tornadoes may also occur, especially with
    portions of the QLCS that interact with an approaching warm front. A
    Tornado Watch may need to be issued in the next couple of hours.

    ..Squitieri/Smith.. 05/17/2026

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!9AC7e_-DsgcTdriXVrrROKZ2TJ1F7dRiN2e0ghZWsVetzJNgvnbjpj3Wh0EsGhbsRtpDKn-Fr= sedrgc2WWZi8cQxHbA$ for graphic product...

    ATTN...WFO...ARX...MPX...DMX...FSD...

    LAT...LON 42589521 44019511 44269487 44329424 44209347 43859281
    43459256 42919281 42629326 42429418 42469470 42589521=20

    MOST PROBABLE PEAK TORNADO INTENSITY...100-125 MPH
    MOST PROBABLE PEAK WIND GUST...65-80 MPH
    MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN


    =3D =3D =3D
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    * Origin: Capitol City Online (1:2320/107)