• MESO: Mesoscale Discussion 1684

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Fri Jul 19 21:51:16 2024
    ACUS11 KWNS 192151
    SWOMCD
    SPC MCD 192150=20
    NEZ000-SDZ000-COZ000-WYZ000-192345-

    Mesoscale Discussion 1684
    NWS Storm Prediction Center Norman OK
    0450 PM CDT Fri Jul 19 2024

    Areas affected...southwest South Dakota and west-central Nebraska

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

    Valid 192150Z - 192345Z

    Probability of Watch Issuance...40 percent

    SUMMARY...Thunderstorms should gradually increase in coverage and
    intensity this afternoon/evening. A risk for hail and damaging gusts
    may evolve. A WW is possible.

    DISCUSSION...As of 2140 UTC, regional radar and satellite imagery
    showed isolated thunderstorms developing near a frontal zone across
    southern SD, northern NE and eastern WY. Warming afternoon surface
    temperatures in the 80s to 90s F with 50s and 60s F dewpoints are
    supporting moderate buoyancy of 1500-2500 J/kg across southern SD
    and western NE. Enhanced mid-level flow ahead of a weak perturbation
    was observed on area VADs, with effective shear of 35-45 kt.
    Isolated organized storms, including supercells, appear possible
    given the favorable CAPE/shear overlap. While mid-level lapse rates
    are not overly steep (7-7.5 C/km), the moderate buoyancy and
    potential for updraft rotation suggest a risk for hail with the
    stronger storms. Damaging gusts are also possible with LCL heights
    above 2,000 m.

    Additional storm development/intensification will remain possible
    late this afternoon and into the evening as weak ascent continues to
    overspread the central High Plains. Exact storm coverage remains
    uncertain given the relatively narrow zone of buoyancy and cloud
    debris from earlier convection. Still, some CAM guidance suggests a
    cluster or storms may eventually evolve with the potential for hail
    and damaging winds across parts of southwest SD and west-central NE.
    While convective evolution and the degree of severe risk remains
    unclear, conditions will be monitored for a possible WW.

    ..Lyons/Gleason.. 07/19/2024

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!6lySsJlZknz7V8O1We1PHvF6GC1UM-teiPeW6PP7mVzxvpIcdObTpL_hRqFECygKOy_J-wEAU= JKRwaJwlg4XrLjK9K8$ for graphic product...

    ATTN...WFO...LBF...UNR...BOU...CYS...

    LAT...LON 41130338 43940444 44580391 44430294 42640044 41980025
    41370043 40930153 41050308 41130338=20


    =3D =3D =3D
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