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