968
FXUS65 KMSO 200918
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
218 AM MST Thu Nov 20 2025

.DISCUSSION...

KEY MESSAGES:

-  Reduced visibility due to valley fog during the morning
   commute today.

 - Mild Weekend: continued unseasonably warm temperatures (10 to
   15 degrees above average) are expected this weekend, with
   spotty rain showers.

 - Monday Cold Front: A sharp change in weather arrives Monday,
   bringing strong winds, cooler temperatures, and snow to
   mountain passes.

Satellite imagery early this morning is indicating low stratus
clouds over the valleys of the Northern Rockies. Valley fog could
thicken for this mornings commute. The extent of fog will depend
on where the stratus deck gives way to clearing skies. Where skies
can clear, low level cooling will bring in the fog. The
Bitterroot, Missoula, Flathead, and Mission valleys will all be
suspect for decreased visibility this morning. Upper level flow
will become northwesterly today. Some chances for precipitation
will stay in the forecast for Clearwater range, especially in the
higher terrain, while western Montana and the rest of north-
central Idaho stays mostly dry under low stratus decks to start
the day. Chances for precipitation will shift northwards into
northwest Montana on Friday.

Mild weather will continue this weekend as daytime high
temperatures will be about 10 degrees above normal. Enough
moisture remains embedded in the westerly flow aloft to keep
precipitation in the forecast (20 to 40 percent chance) for
northwest and west-central Montana, as well as the northern
Clearwater range, on Saturday and Sunday. On Monday, the polar jet
drops south over the Northern Rockies, bringing a change to the
mild fall weather.

A trough of low pressure and an associated cold front will
accompany the change in position of the jet on Monday. Expect:

 - Wind: This will be a breezy system. Current probabilities show
   a 50% chance of wind gusts exceeding 50 mph along the
   Continental Divide and near Anaconda. The Bitterroot and
   Mission Valleys will see a 20-30% chance of similarly high gusts.

 - Mountain Snow: While not a massive snow producer, the front
   will bring accumulating snow to the passes. Preliminary
   forecasts indicate Trace to 3 inches for Lookout Pass and Trace
   to 6 inches for Marias Pass.

 - Cooling: Behind the front, temperatures will drop back to
   near- seasonal normals.

Looking ahead to the holiday travel period (Wednesday and
Thanksgiving Day), forecast models have trended drier. While early
indications suggested an active storm, the current consensus
points toward seasonable temperatures and mainly dry conditions,
though a few light mountain snow showers cannot be ruled out. It
is worth noting that the pattern is still evolving. Travelers
should monitor updates, as even small shifts in the jet stream
could re-introduce light snow to the forecast for both valley and
pass-level travel.

The day after Thanksgiving can be a busy travel day, and the
weather pattern looks unsettled. The NBM has 20 to 40 percent
chance for snow in the valleys, and 60 to 80 percent chance for
snow occurrence in the mountains.


&&

.AVIATION...Fog is already impacting KBTM and KSMN early this
morning. Expect decreases in visibility and ceiling into mid
morning at all Northern Rockies terminals. Visibility down to
1/4SM will be possible. Chances for visibility reductions due to
fog last through mid morning. Once the fog lifts, precipitation
will be limited to Idaho and Clearwater counties (about 30%
chance) through this evening, obscuring terrain over the
Clearwater and Bitterroot mountains. There is about a 20% chance
for more fog on Friday morning.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&

$$