296
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

$$