586
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.
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