Subj : MESO: Mesoscale Discussion 1970
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Sun Aug 17 2025 03:24:43

ACUS11 KWNS 170324
SWOMCD
SPC MCD 170323=20
SDZ000-NDZ000-MTZ000-WYZ000-170530-

Mesoscale Discussion 1970
NWS Storm Prediction Center Norman OK
1023 PM CDT Sat Aug 16 2025

Areas affected...far eastern Wyoming...western into central South
Dakota...extreme southeast Montana...and southern North Dakota

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

Valid 170323Z - 170530Z

Probability of Watch Issuance...80 percent

SUMMARY...Thunderstorms continue to gradually strengthen and
increase in coverage. An increasing potential for damaging
thunderstorm winds will likely warrant the need for a severe
thunderstorm watch this evening/overnight.

DISCUSSION...Thunderstorm organization and intensity continues to
gradually increase this evening across northeast Wyoming and far
western South Dakota. This is likely in response to increasing
large-scale ascent as an upstream short-wave trough approaches the
region. The airmass along and immediately ahead of the shortwave
remains strongly unstable (MUCAPE up to 3000 J/kg) and sufficiently
sheared (ESHR around 35 knots) to support severe thunderstorms.=20

Current expectation is that these thunderstorms will continue to
intensify and organize as they move into the more unstable
environment and the nocturnal low-level jet strengthens. The primary
severe threat should be damaging thunderstorm winds driven by
internal MCS dynamics. That said, this evening's 00Z UNR (Rapid
City, SD) sounding sampled sufficiently steep mid-level lapse rates
to support at least some potential for large hail.=20

Trends will continue to be monitored, but it is increasingly likely
that a severe thunderstorm watch will be needed in the next 1-2
hours.

...Marsh/Smith.. 08/17/2025

....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj=
g!6q2MhTT45Dxo1JtbkUkTryBlXEkcXGtMwniZUwQthOm4UWnDPf-t5p8SVmAI0KoVYJ1nafu9G=
YHEzWstV6pDQnUqwoE$  for graphic product...

ATTN...WFO...ABR...BIS...UNR...CYS...BYZ...

LAT...LON   43650119 43030270 43170406 43910496 44810497 45790423
            46750148 46680021 45889966 44979935 44219963 43650119=20

MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN


=3D =3D =3D
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