980 
FXUS65 KMSO 200806
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
206 AM MDT Mon Oct 20 2025

.DISCUSSION...

KEY MESSAGES:

- A ridge builds over the region causing mild conditions through
  most of the week. 

- Stable conditions under the ridge will promote valley fog this
  week. 

- Another atmospheric river event is in the forecast for next
  weekend. 

During the morning commute watch for icy roads above 5000 feet as
a little wet snow is expected through the morning. In the valleys
be prepared for fog, although there is sufficient flow aloft that
fog development may be inhibited. 

The rest of this week temperatures rebound, almost 10 to 15
degrees above normal by Friday. Each morning with stable
conditions valley fog will be possible persisting into the 
afternoon.

Ensembles agree well on another atmospheric river arriving for
next weekend. Of course at that lead time, there are considerable
differences in the timing and intensity, but the overall message
is that another round of moderate and high elevation snow is
expected next weekend. Even low end forecasts (10th percentile)
are showing a few inches of snow above 6,000 feet late next
weekend or early next week, with high end forecasts (90th
percentile) showing a few tenths of an inch down to the valley
floors in western Montana. 

&&

.AVIATION...Expect low to moderate ceilings to persist behind the
cold front pushing the atmospheric river out of the region 
through Tuesday morning. The recent moisture and clearing skies 
mid-week are causing concerns for dense valley fog this week.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory until 9 AM MDT this morning for 
     Bitterroot/Sapphire Mountains...Potomac/Seeley Lake 
     Region...West Glacier Region.

ID...Winter Weather Advisory until 8 AM PDT Monday for Southern 
     Clearwater Mountains.

&&

$$