540
FXUS65 KMSO 272014
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
114 PM MST Thu Nov 27 2025

.DISCUSSION...

KEY MESSAGES:

-  Major winter weather impacts expected tonight through Friday,
   widespread snow, strong winds and much colder temperatures.

-  Coldest minimums so far this season during the weekend

-  Active weather next week with potential of widespread snow on
   Tuesday and Thursday


A Pacific low pressure system will continue to move westward this
afternoon causing widespread precipitation. Snow levels will be
hovering around 6000 feet south of I-90 corridor this afternoon
and evening. While areas north of the interstate will have snow
levels between 3000-4000 feet. The moisture associated with this
low pressure system will begin to interact with an arctic front
pushing over the Continental Divide this evening around Glacier
National Park and Marias Pass. This interaction will cause an
enhancement in the snow production of Hwy 2 along with gusty
easterly winds and rapidly dropping temperatures. The combination
of snow, wind and potential freeze up of roadways will create
hazardous to dangerous conditions so a winter storm warning is in
effect.

The low pressure system will weaken and start to move southward
overnight pulling the shield of precipitation to the south. The
latest model guidance is showing the precipitation to begin to
diminish by the time the arctic air infiltrates the Flathead
valley down into the Mission valley. This arctic air appears to
cause wind gusts up to 40 mph along with rapidly dropping
temperatures. The strongest winds are expected near Badrock
canyon. Wet and snow covered roadways have the potential to become
icy tonight as the cold air settles into the valleys.

The models are showing that the arctic boundary will start to
interact with the precipitation around Ovando, Helmville and
Garrison junction region late tonight into Friday morning. Heavy
snow, wind gusts to 40 mph and rapidly dropping temperatures will
once again be the main concern. The arctic boundary appears to
push this heavy snow over the I-90 corridor from Clinton to Deer
Lodge, so a winter storm warning is in effect for this region.

The remainder of the region will experience gusty easterly winds,
widespread snow and significantly cooler temperatures, but not to
the extent that would warrant a dangerous conditions. If you are
heading out on Friday prepare for significant winter conditions
especially across western Montana.

A subtle disturbance appears to slide through the Northern Rockies
on Saturday under northwesterly flow aloft which should help pull
a little more arctic air into the Northern Rockies. Partial clear
skies Friday night and Saturday night should allow for
temperatures to drop dramatically overnight to some of the coldest
readings experienced so far this season. Western Montana will have
temperatures in the single digits by Sunday morning with a few
valleys having the potential of dropping below zero. While the low
valleys of Idaho and Clearwater counties having morning readings
in the mid teens to mid 20 degrees.

The majority of the model clusters is showing a disturbance moving
across the Northern Rockies Tuesday into Wednesday bringing
widespread snow. Then around 25% of the models have a second
disturbance impacting the region by the latter part of the work
week. The trajectory of these storms along with entrenched cold
air would indicating that the Northern Rockies would experience
mainly snow with the mountains potentially getting a significant
amount.


&&

.AVIATION...Low-to-mid level cloud cover is still in place across
the airspace along and north of I-90. Cloud cover will continue to
increase through the evening and overnight. Mountain obscurations
will become increasingly widespread. Precipitation will begin to
increase in intensity overnight. Strong low-level north and
easterly winds will develop into Friday morning especially near
and along the Continental Divide. Timing of the surface front will
be close to 28/0700z at KGPI, around 28/1400z at KMSO, and
after 28/1900z at KBTM. Weather conditions will further
deteriorate with the frontal passage creating periods of
visibility less than 1sm at times with low ceilings and heavy
snowfall intensities. Surface wind gusts may reach 35 knots along
and behind the front.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory from 11 PM this evening to 5 PM MST
Friday for Bitterroot/Sapphire Mountains...Kootenai/Cabinet
Region...Lower Clark Fork Region...Missoula/Bitterroot Valleys.

     Winter Storm Warning from 5 PM this afternoon to 2 PM MST Friday
     for West Glacier Region.

     Winter Weather Advisory from 6 PM this evening to 5 PM MST
     Friday for Flathead/Mission Valleys.

     Winter Storm Warning from 2 AM to 6 PM MST Friday for
     Butte/Blackfoot Region...Potomac/Seeley Lake Region.

ID...Winter Weather Advisory from 10 PM this evening to 4 PM PST
     Friday for Southern Clearwater Mountains.

&&

$$