MD 2126 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR PORTIONS OF EASTERN WYOMING INTO FAR SOUTHWESTERN SOUTH DAKOTA AND NORTHWESTERN NEBRASKA PANHANDLE
Mesoscale Discussion 2126
NWS Storm Prediction Center Norman OK
0519 PM CDT Sat Sep 09 2023
Areas affected…portions of eastern Wyoming into far southwestern
South Dakota and northwestern Nebraska Panhandle
Concerning…Severe potential…Watch possible
Valid 092219Z – 092345Z
Probability of Watch Issuance…40 percent
SUMMARY…The severe threat may be increasing across portions of the
northern High Plains. The strongest storms may produce a few bouts
of severe hail or wind. A Severe Thunderstorm Watch issuance may be
needed if more widespread convective coverage becomes evident.
DISCUSSION…Convective initiation has occurred along the lee of the
Rockies in eastern WY while multicells/transient supercells have
become established across southwestern SD. The SD storms are
expected to remain confined to the more favorable terrain, with a
persistent but sparse severe wind/hail threat. However, the storms
should intensify and move off of the higher terrain in WY as a weak
mid-level impulse crests the synoptic ridge and ejects into the
central High Plains. Boundary-layer moisture is meager. However,
steep low and mid-level lapse rates are contributing to 1000+ J/kg
MLCAPE, which is adequate to support some severe wind/hail with
supercells that can develop given elongated hodographs and 40-50 kts
of effective bulk shear. Nonetheless, discrete storms and their
severe threat should be isolated, so convective trends are being
closely monitored for greater storm coverage and the need for a
Severe Thunderstorm Watch issuance.
..Squitieri/Thompson.. 09/09/2023
…Please see www.spc.noaa.gov for graphic product…
ATTN…WFO…UNR…CYS…BYZ…RIW…
LAT…LON 41550500 43390680 44680696 44980582 44820466 44300337
43710285 43220272 42680299 41760401 41550500
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