• MESO: Mesoscale Discussion 0875

    From COD Weather Processor@1:2320/107 to wx-storm@lists.illinois.edu on Wed May 27 16:31:57 2026
    ACUS11 KWNS 271631
    SWOMCD
    SPC MCD 271631=20
    MDZ000-VAZ000-NCZ000-WVZ000-OHZ000-KYZ000-271830-

    Mesoscale Discussion 0875
    NWS Storm Prediction Center Norman OK
    1131 AM CDT Wed May 27 2026

    Areas affected...portions of the Ohio valley and Mid Atlantic

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

    Valid 271631Z - 271830Z

    Probability of Watch Issuance...60 percent

    SUMMARY...Scattered to numerous thunderstorms are expected this
    afternoon across parts of southern OH and northeastern KY into WV
    and the DelMarVA. A mixed storm mode should promote a risk for
    damaging gusts, though some hail is also possible. One or more
    severe thunderstorm watches will probably be issued in the next
    couple of hours.

    DISCUSSION...As of 1630 UTC, visible and radar imagery showed
    initial thunderstorms gradually intensifying over the OH Valley with
    clearing and deepening cumulus farther east. Weak ascent from a
    broad upper trough over the northern Great Lakes is overspreading an
    east-west frontal zone amidst midday heating. To the south of the
    front, a very moist air mass is in place with dewpoints in the low
    70s F. As surface temperatures warm near 80 F, destabilization
    should continue this afternoon. Despite modest mid-level lapse
    rates, 1000-1500 J/kg of MLCAPE and little inhibition will allow for
    scattered to widespread thunderstorms.

    A belt of enhanced westerly flow associated with the upper trough
    will continue to shift eastward near the front supporting modest
    deep-layer shear around 20-25 kt. Initial storms over OH and KY are
    likely to be multi cellular with brief organization potential and
    some clustering. As deep-layer shear increases to 30-35 kt over WV
    and the Mid Atlantic states, a few marginal supercell structures and
    some linear segments are also possible.

    As thunderstorms develop and eventually cluster, damaging gust
    potential should increase this afternoon over the OH Valley, with
    additional development and the severe threat spreading eastward with
    time. The brief stronger updrafts may also pose a risk for some
    hail, but mid-level temperatures and lapse rates are not overly
    favorable. Hail potential may be maximized with any storms that
    remain more discrete.

    Confidence in a sustained severe risk is highest farther east where
    the best overlap of deep-layer shear and buoyancy are expected
    (WV/VA into southern MD/DE). Given the expected increase in severe
    potential this afternoon, a WW is possible in the next couple of
    hours.

    ..Lyons/Gleason.. 05/27/2026

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!9gjldjaclNVT88TKoOXOwFgAPm5WWiJ7NyvIyMaEA5Swws6dcPWuoDQCPJPDsRGzHbJJ_hMhK= JFOOsBtjRbNKMo2GWw$ for graphic product...

    ATTN...WFO...AKQ...LWX...RAH...RNK...PBZ...RLX...JKL...ILN...

    LAT...LON 37388207 38458274 38908272 39778148 39838111 39277960
    38747775 38487633 38387501 36917591 36317558 36257640
    36407905 37388207=20

    MOST PROBABLE PEAK WIND GUST...55-70 MPH
    MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN


    =3D =3D =3D
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