Thompson Falls, Montana Weather Forecast Discussion

562
FXUS65 KMSO 220828
AFDMSO
Area Forecast Discussion
National Weather Service Missoula MT
228 AM MDT Mon Sep 22 2025
.DISCUSSION...
KEY MESSAGES:
- Widespread valley frost possible Tuesday morning, especially
  western Montana.
- Warming and drying trend through late week.
The cold front that brought widespread showers and isolated
thunderstorms to the region yesterday has moved east of the
Continental Divide this morning. Isolated rain showers have
lingered overnight on the backside of the trough and will continue
to move east through the morning hours. For most, today will be
mostly sunny with afternoon temperatures around normal for this
time of year; however, smoke from wildfires in Washington may
cause hazy skies, especially in north-central Idaho and west-
central Montana this afternoon and Tuesday.
With clearing skies, diminishing winds, and a cool, dry airmass
moving in, conditions will become favorable for the first
widespread valley frost of the season Tuesday morning. Sheltered,
low-lying areas across western Montana and the higher valleys of
north-central Idaho have the highest potential for seeing
temperatures drop to near or below freezing. The probability for
frost is highest (90%) in the Deer Lodge, Butte, and Anaconda
areas, with lower probabilities (50-70%) for the valleys along
Highway 93.
High pressure will build back over the Northern Rockies mid-week,
causing high temperatures to moderate. Afternoon temperatures are
expected to return to the low to mid-80s in western Montana and
low 90s in north-central Idaho by Wednesday. These temperatures
will remain 10 to 15 degrees above normal until Friday, when the
ridge begins to flatten, ushering in another day of breezy
westerly winds.
&&
.AVIATION...VFR conditions will prevail for most of the period
across western Montana and north-central Idaho. Lingering isolated
rain showers on the backside of a departing trough may bring brief
lowering ceilings along the Continental Divide through 15Z this
morning. Clear skies and calm winds overnight will be conducive to
widespread valley frost development by Tuesday morning.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&
$$

NWS MSO Office Area Forecast Discussion