ACUS11 KWNS 181951
SWOMCD
SPC MCD 181951
MTZ000-WYZ000-IDZ000-182115-

Mesoscale Discussion 2026
NWS Storm Prediction Center Norman OK
0251 PM CDT Tue Aug 18 2026

Areas affected...southern Montana and far northern Wyoming.

Concerning...Severe potential...Watch possible

Valid 181951Z - 182115Z

Probability of Watch Issuance...60 percent

SUMMARY...Isolated strong to severe storms are possible this
afternoon/evening across southern Montana and far northern Wyoming.

DISCUSSION...Storm coverage has increased across central and
southern Montana over the last hour ahead of a mid-level shortwave
trough. Relatively weak instability is in place amid mostly 40sF
dewpoints. However, strong heating (mid to upper 80s) has yielded
steep lapse rates across the region. Moderate mid-upper level flow
(40-55 kts) will support storm organization including the potential
for supercells. The weak instability should limit the hail threat
somewhat, but the steep lapse rates and dry sub-cloud layer should
support some severe wind threat, including the potential for a few
75+ mph wind gusts.

Expect storms to remain mostly cellular which may limit a more
widespread severe wind threat. However, the stronger cores which
develop may be efficient wind producers. The downstream threat
across northern Wyoming remains uncertain due to extensive cloud
cover and limited heating.

..Bentley/Guyer.. 08/18/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fjg!_47NcdwQjYvjBKqD-2WG7Ti4acrPcMn-5l1ZatYXkmWmiavY6MWHAl_9FZQ-7OUMYIhDWsrXzxAopc14r2fnT0VPdBE$ for graphic product...

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

LAT...LON 47280983 47230752 47090704 46760586 46080555 45370552
44790570 44520692 44401010 44791160 46081135 47280983

MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN


= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)