ACUS11 KWNS 072259
SWOMCD
SPC MCD 072259 
MTZ000-WYZ000-080100-

Mesoscale Discussion 1535
NWS Storm Prediction Center Norman OK
0559 PM CDT Tue Jul 07 2026

Areas affected...Southern/southeast Montana into far northern
Wyoming

Concerning...Severe potential...Watch possible 

Valid 072259Z - 080100Z

Probability of Watch Issuance...40 percent

SUMMARY...An environment favorable for supercells remains in place
across southeast Montana, and new updraft development is noted
across the region. It is uncertain how many storms will develop, but
some severe hail and wind risk may materialize in the coming hours.

DISCUSSION...Latest GOES day cloud phase imagery shows several
attempts at initiation along the terrain in central to southeast
Montana within a weak upslope flow regime. Earlier attempts at deep
convection have struggled to intensify away from the terrain, but
synoptic-scale ascent continues to overspread the region as a
mid-level wave traverses the international border. Recent HRRR and
RAP forecast soundings appear to be capturing the near-storm and
downstream environments well and depict very limited inhibition in
place, which suggests that deep/robust convection remains possible
if storms can be maintained away from their zones of ascent. 

In general, the downstream environment can be characterized as
favorable for supercell development given around 1000-1500 J/kg
MLCAPE and 30-35 knots of effective bulk shear, and more aggressive
members of the HRRR/RRFS time-lagged ensemble depict at least
isolated supercell development through 02 UTC. However, these same
ensemble solutions show generally low thunderstorm coverage and low
probabilities for intense convection, which reflects the uncertainty
pertaining to thunderstorm maintenance away from the terrain. Trends
will continue to be monitored, and watch issuance may be needed if
it appears likely robust storms will be sustained within the open
warm sector.

..Moore/Gleason.. 07/07/2026

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

ATTN...WFO...UNR...BYZ...GGW...RIW...TFX...

LAT...LON   44640691 45060812 45390881 45820908 46580907 47170900
            47500878 47620838 47640793 47470738 47170680 46390541
            46080511 45600497 45210511 44820558 44650594 44590629
            44640691 

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