• MESO: Mesoscale Discussion 2020

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Fri Aug 29 19:14:33 2025
    ACUS11 KWNS 291914
    SWOMCD
    SPC MCD 291913=20
    NEZ000-SDZ000-KSZ000-COZ000-292115-

    Mesoscale Discussion 2020
    NWS Storm Prediction Center Norman OK
    0213 PM CDT Fri Aug 29 2025

    Areas affected...portions of Nebraska...Southern South Dakota
    Northeastern Colorado and far northwest Kansas

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

    Valid 291913Z - 292115Z

    Probability of Watch Issuance...40 percent

    SUMMARY...Scattered to strong to severe storms are expected this afternoon/evening. A few supercells may organize with a risk for
    hail and damaging gusts. A WW is being considered.

    DISCUSSION...As of 1910 UTC, regional radar and satellite imagery
    showed initial convective development was underway across parts of
    the central Plains. Weak ascent from a shortwave trough exiting the
    Rockies will continue to overspread a warming air mass ahead of a
    weak lee trough/low over western NE. With little remnant inhibition
    (from the 18z LBF sounding), continued diurnal heating will result
    in gradual destabilization with menial mid-level lapse, generally
    less than 7 C/km. Despite the poor lapse rates, MLCAPE 500-1000 J/kg
    should be sufficient for scattered strong to occasionally severe
    storms. Elongated hodographs, owing to 40-50 kt of deep-layer flow,
    will support storm organization into clusters and a few supercells.
    Hail will be possible along with damaging winds given the high PWAT
    air mass.

    Confidence in the timing and general convective evolution is low
    owing to modest forcing for ascent. The poor lapse rates also
    suggest storm organization may be somewhat slow initially as
    updrafts gradually build in intensity. However, CAM guidance does
    show stronger, likely organized, storms eventually evolving over
    portions of central and southern NE later this afternoon. Given the
    expected increase in storm coverage and potential for organized
    supercells with a severe risk, a WW is possible.

    ..Lyons/Mosier.. 08/29/2025

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!4ynYIBhV_7ulhJcm5HTx0KmBT3MivlYBuRR_2U2V-LXj9ACpbZtyBEs-zem3oSAkvgYlA6AWp= yGz201qrbGzd3Pc4yo$ for graphic product...

    ATTN...WFO...FSD...GID...LBF...UNR...GLD...BOU...CYS...

    LAT...LON 40159973 39920004 39370089 39050265 39710345 40730280
    41410243 42730189 43470141 43630041 43469957 42329845
    41189879 40159973=20

    MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
    MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
    MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN


    =3D =3D =3D
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