FXUS65 KMSO 121102

AFDMSO



Area Forecast Discussion

National Weather Service Missoula MT

402 AM MST Fri Dec 12 2025



.DISCUSSION...



KEY MESSAGES:



-  Flooding threat continues in far northwest Montana but

   conditions are improving.



-  Arctic air and snow expected for Glacier National Park area

   today.

   

-  Ridge of high pressure this weekend then return to a very

   active weather pattern next week. 



The remnants of the atmospheric river continues to stream across 

north central Idaho into west central Montana this morning. The 

moisture plume moves back to the north throughout the day once 

again bringing rain to northwest Montana. The exception will be 

over Glacier National Park where arctic air is starting too 

infiltrate the area causing snow levels to drop to valleys. 

Marias pass is reporting single digit temperatures as the air 

moves down the Hwy 2 corridor towards West Glacier. A winter 

weather advisory is in effect for the area as light snow 

accumulations and pockets of freezing rain is expected in the 

region. 



The flooding appears to be improving across Sanders and Lincoln

county tonight, but the rivers and streams will remain extremely

high for another 24 hours. The rain that returns this afternoon

and evening will be capable of putting down an additional 0.1 to

0.25 inches. 



A ridge of high pressure will be building over the region this

weekend causing a respite in the precipitation. Valley inversions

are expected to develop this weekend with a high probability of

fog and low stratus developing due to the extreme moist

environment left behind after this past rain event. 



The ridge will be short lived as the Northern Rockies return to a

very active weather pattern next week. The first shot of moist

pushes into the region Monday through Tuesday as snow levels will

remain very high, around 7000. Widespread rain is anticipated for

the Northern Rockies which could bring about another round of

hydrological issues. Then a cold front pushes across the region

Tuesday night into Wednesday. This front will bring snow levels

down to the valley floor, but strong westerly winds will be

present. This showery and breezy pattern is expected to last

through the remainder of the week into the following weekend.





&&



.AVIATION...Rain is currently over north central Idaho into

western Montana. KMSO will continue to be impacted by the rain

until the afternoon along with fog. The moisture shifts to the

north by this afternoon causing rain at KGPI with the potential of

reduced visibility. Also an arctic airmass is filtering over the

Continental Divide near Glacier National Park causing snow levels

to drop to valley floors. 



&&



.MSO WATCHES/WARNINGS/ADVISORIES...

MT...Winter Weather Advisory until 5 AM MST Saturday for West Glacier 

     Region.



ID...None.

&&



$$