ACUS11 KWNS 081940
SWOMCD
SPC MCD 081939 
SDZ000-MTZ000-WYZ000-082145-

Mesoscale Discussion 1543
NWS Storm Prediction Center Norman OK
0239 PM CDT Wed Jul 08 2026

Areas affected...portions of southeastern Montana and northern
Wyoming into far western South Dakota

Concerning...Severe potential...Watch possible 

Valid 081939Z - 082145Z

Probability of Watch Issuance...40 percent

SUMMARY...Widely scattered, high-based thunderstorms will pose a
risk for damaging/severe wind gusts and isolated large hail this
afternoon and evening. Trends are being monitored for a potential
Severe Thunderstorm Watch.

DISCUSSION...Scattered, high-based thunderstorm development is
ongoing across the high-terrain of southern Montana and northern
Wyoming as of 1930 UTC. Continued insolation amid modest low-level
moisture (dewpoints ranging from the mid-40s to low-50s F) will
continue to support an increase in thunderstorm coverage through the
afternoon. Modifying the 18z RIW observed sounding for recent
observations depicts steep low- and mid-level lapse rates with
MLCAPE of 500-1000 J/kg. This dry boundary layer profile will
support efficient evaporative cooling and cold pool development,
with recent high-res guidance continuing to suggest the development
of one or more linear clusters/segments through the afternoon. As
this occurs, an increase in the threat for damaging/severe wind
gusts is expected as convection progresses eastward amid deep-layer
westerly flow. Isolated large hail also cannot be ruled out with the
strongest cores given steep mid-level lapse rates and modest
effective shear of 25-30 kts. 

While the general expectation is for the severe risk to remain more
limited in coverage compared to areas farther south across the
central High Plains, a Severe Thunderstorm Watch may be needed in
the next 1-2 hours should a corridor of greater severe potential
become evident.

..Chalmers/Hart.. 07/08/2026

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

ATTN...WFO...UNR...BYZ...RIW...

LAT...LON   43530526 43480807 43680886 43990968 44441043 44741072
            45031085 45591070 45831015 46090865 46020696 45590542
            45100404 44730370 44260363 43900375 43670431 43530526 

MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN