ACUS01 KWNS 200032

SWODY1

SPC AC 200031



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

0731 PM CDT Tue Aug 19 2025



Valid 200100Z - 201200Z



...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS EVENING

INTO THE OVERNIGHT HOURS ACROSS PARTS OF WESTERN INTO NORTH CENTRAL

MONTANA...



...SUMMARY...

Strong to severe wind gusts may develop with a consolidating cluster

of thunderstorms across western through north central Montana this

evening into the overnight hours.



...01Z Update...



...Northern Rockies...

Thunderstorms have begun to initiate across the Bitterroots

vicinity, with deepening convection also evident to the lee of the

mountains of western Montana, between Great Falls and Cut Bank. 

Although the hot and deeply mixed boundary layer which has evolved

across the region appears only characterized by weak CAPE, models

suggest that mid-level forcing for ascent overspreading the region

will probably become supportive of a consolidating cluster, in the

presence of cloud-bearing layer mean flow strengthening to 30-40+

kt.  Even with onset of boundary-layer cooling within the next

couple of hours, sub-cloud thermodynamic profiles will remain

conducive to strengthening downward momentum transfer accompanied by

surface gusts approaching or exceeding severe limits.  As convection

approaches better boundary-layer moisture across the Havre vicinity

by late evening, more unstable updraft inflow might support further

intensification of thunderstorms before spreading across the

international border.



..Kerr.. 08/20/2025



$$