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  • MESO: Mesoscale Discussion 1233

    From COD Weather Processor@1:2320/107 to wx-storm@lists.illinois.edu on Sun Jun 21 21:24:13 2026
    ACUS11 KWNS 212124
    SWOMCD
    SPC MCD 212123=20
    OHZ000-KYZ000-INZ000-ILZ000-212300-

    Mesoscale Discussion 1233
    NWS Storm Prediction Center Norman OK
    0423 PM CDT Sun Jun 21 2026

    Areas affected...Southern and Central Indiana

    Concerning...Severe potential...Watch needed soon=20

    Valid 212123Z - 212300Z

    Probability of Watch Issuance...95 percent

    SUMMARY...The tornado threat is increasing across portions of
    southern Indiana as thunderstorms with a history of producing
    tornadoes across southern Illinois move east into the area. A
    tornado watch will be needed soon.

    DISCUSSION...Several supercells with a history of producing
    tornadoes have developed this afternoon across portions of southern
    Illinois in association with a convectively augmented vorticity
    maximum moving east within zonal mid-level flow. Ahead of these
    supercells, a surface boundary is slowly lifting northward across
    portions of Indiana. To the south of this boundary, surface
    dewpoints have risen into the 60Fs to low 70Fs contributing to
    MLCAPE values between 500-1000 J/kg. Along the boundary easterly
    low-level flow will maximize storm-relative helicity, as indicated
    by the Indianapolis VAD (KIND) which suggests around 300 m2/s2. The
    result will be a continued tornado threat this evening across
    portions of southern and central Indiana and a tornado watch will be
    required soon.

    ..Marsh/Smith.. 06/21/2026

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!-uM2ZjrzINgr6ohV1XYIZ7nquZQlG4Y0i15xq-KxAL_Vh-cHbCF1N0R0floOzEbQ2GO0cghaQ= sfLeoOVVpdvQYamVSA$ for graphic product...

    ATTN...WFO...ILN...LMK...IND...ILX...

    LAT...LON 39798785 40148739 40348673 40268550 39928483 39418459
    38868482 38618545 38558629 38628775 39798785=20

    MOST PROBABLE PEAK TORNADO INTENSITY...100-125 MPH
    MOST PROBABLE PEAK WIND GUST...65-80 MPH
    MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN


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