338
FXUS65 KMSO 121321 CCA
AFDMSO
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE MISSOULA MT
621 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 TO
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 MOISTURE
PUSHES INTO THE REGION MONDAY THROUGH TUESDAY AS SNOW LEVELS WILL
REMAIN VERY HIGH, AROUND 7000 FEET. 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.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page