458
ACUS11 KWNS 210003
SWOMCD
SPC MCD 210002
MTZ000-210230-

Mesoscale Discussion 1997
NWS Storm Prediction Center Norman OK
0702 PM CDT Wed Aug 20 2025

Areas affected...portions of north-central into northeastern Montana

Concerning...Severe potential...Watch unlikely

Valid 210002Z - 210230Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated supercells should persist across portions of
north-central into northeastern Montana over the next few hours,
accompanied by a severe hail and wind threat.

DISCUSSION...Two dominant, discrete supercells have materialized
over the past few hours, with severe gusts reported and MRMS mosaic
MESH data suggesting hail over 1.5 inches in diameter occurring.
These storms are rapidly progressing eastward amid strong mid- to
upper-level flow associated with a 300 mb jet streak. 40 kts of
effective bulk shear is present, and is coinciding with 1000-1500
J/kg MLCAPE, driven mainly by 8.5+ C/km mid-level lapse rates. Given
this environment, supercells should continue eastward for at least a
few more hours, with severe gusts potentially reaching 75 mph, along
with 1.5+ inch diameter hail. Despite the severe conditions
associated with these storms, the severe threat should remain
isolated and localized, given the low coverage of storms. As such, a
WW issuance is not currently anticipated.

..Squitieri/Mosier.. 08/21/2025

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...GGW...TFX...

LAT...LON   47150948 47330982 47670998 48460990 48840937 48960660
            48640613 48210595 47650610 47230650 47070722 47080819
            47090889 47150948

MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN