634
FXUS65 KMSO 012004
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
204 PM MDT Mon Sep 1 2025

.DISCUSSION...

KEY MESSAGES:

-  Isolated thunderstorms afternoon hours and evening, mainly
   focused to western Montana

-  Warming and drying trend through the weekend with localized
   heat impacts through at least Wednesday

Radar and satellite imagery is indicating convection to start to
develop across portions of west central Montana this afternoon
especially along the Continental Divide. A subtle disturbance is
expected to move into northwest Montana later this afternoon into
the evening which has the potential to kick off a few storms.
Storms will be capable of gusty erratic outflow winds due to dry
low levels, but decent rain is expected under the core of the
storms.

The ridge is still expected to shift to the west over the next
couple of days which will continue the warming and drying trend
over the Northern Rockies. The lower valleys of north central
Idaho and northwest Montana (including Riggins, Orofino, Thompson
Falls and Libby) are expected to reach moderate to major heat risk
conditions due to extreme afternoon temperatures along with warm
minimums. The heat advisory for Idaho will more than likely be
extended but effects from local and regional smoke could hinder
temperatures from reaching their full potential. Also with the
ridge shifting to the west slightly that will cause the Northern
Rockies to experience easterly to northerly winds through at
least Thursday.

The models continue to indicate that the ridge will shift off to
the east by the weekend causing the upper level flow to become
more southwesterly over the Northern Rockies. Temperatures will
cool slightly, but still remain above seasonal averages. This flow
pattern is also conducive to causing convection across the region
as weak disturbances move through the region.


&&

.AVIATION...A few showers and potential thunderstorms are still
anticipated to develop across western Montana this afternoon and
evening, especially along the Continental Divide. Smoke from local
and regional fires will create hazy conditions throughout the
Northern Rockies. MVFR should still be anticipated near local
fires especially during the morning hours.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Heat Advisory from noon Tuesday to midnight MDT Wednesday night
     for Kootenai/Cabinet Region...Lower Clark Fork Region.

ID...Heat Advisory until 9 PM PDT Tuesday for Lower Hells
     Canyon/Salmon River Region...Orofino/Grangeville Region.

&&

$$