• MESO: Mesoscale Discussion 0906

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Tue May 20 18:49:07 2025
    ACUS11 KWNS 201849
    SWOMCD
    SPC MCD 201848=20
    TNZ000-GAZ000-ALZ000-KYZ000-MSZ000-202045-

    Mesoscale Discussion 0906
    NWS Storm Prediction Center Norman OK
    0148 PM CDT Tue May 20 2025

    Areas affected...Northern Alabama...middle Tennessee...and
    south-central Kentucky

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

    Valid 201848Z - 202045Z

    Probability of Watch Issuance...80 percent

    SUMMARY...A tornado watch downstream of WW 303 is expected in the
    next hour or so as T-storms spread from northern MS and western TN
    into northern AL, middle TN, and southern KY.

    DISCUSSION...Sustained convective initiation is well underway across
    central AR to northern MS/western TN as thunderstorms develop along
    a cold front and within the open warm sector due to modest low-level
    warm air advection. This activity is expected to intensify through
    late afternoon and will gradually spread east. Storm-track
    projections suggest that the eastern most storms across northern
    MS/western TN should exit WW 303 by around 20 UTC and spread across
    much of northern AL and middle TN through 00 UTC. Much of northern
    AL was glanced by early-morning/early-afternoon convection, but the
    region largely remains supportive of deep convection with buoyancy characterized by 1500-2000 J/kg MLCAPE. Further north across
    northern middle TN into southern KY, a residual cold pool associated
    with a late-morning QLCS has significantly limited buoyancy for the
    time being. However, 30-35 knot southwesterly flow between 925-850
    mb will advect warm/moist air into the region and promote
    destabilization through late afternoon. (Warm advection is already
    noted on the KOHX VWP between 0-2 km.) Deep-layer wind shear across
    the region should increase through late afternoon as a mid-level jet
    approaches the region and maintains the potential for severe
    convection, which will likely be a combination of organized lines
    and supercells.

    Watch issuance is expected in the next hour or so to address this
    concern, though earlier watch issuance is possible if open warm
    sector convection can develop across northern AL and pose a severe
    threat in the short-term.

    ..Moore/Hart.. 05/20/2025

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!-3hmJZELo1r_EANfkDHuXlTiD-6s3hsp8-Kn1lQSoPNsTH0j2-rUadiy2n2wFMgyQYO_jzhyZ= 7iZsGipLZ5jnoaLmSw$ for graphic product...

    ATTN...WFO...MRX...FFC...LMK...OHX...BMX...HUN...PAH...MEG...
    JAN...

    LAT...LON 33728825 34928796 36778803 37058803 37198777 37308666
    37258613 37118588 36698575 34848558 34108574 33738608
    33468667 33398732 33418786 33548814 33728825=20

    MOST PROBABLE PEAK TORNADO INTENSITY...120-150 MPH
    MOST PROBABLE PEAK WIND GUST...75-90 MPH
    MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN


    =3D =3D =3D
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