029
FXUS65 KMSO 300959
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
251 AM MST SUN NOV 30 2025
DISCUSSION
KEY MESSAGES:
- WIDESPREAD WINTER TRAVEL IMPACTS (MON–TUE): SNOW IS EXPECTED TO
COVER ROADS, CREATING SLICK CONDITIONS.
- ACTIVE PATTERN CONTINUES (LATE WEEK): A MIX OF MOISTURE AND
COLD GROUND TEMPERATURES COULD BRING ADDITIONAL ROUNDS OF SLICK
TRAVEL.
UPCOMING WIDESPREAD WINTER SYSTEM MONDAY–TUESDAY: SLICK TRAVEL
IMPACTS ARE EXPECTED IN BOTH MOUNTAINS AND VALLEYS FROM MONDAY
THROUGH TUESDAY. THIS IS DUE TO A STEADY SNOW EVENT ENABLED BY THE
COLD AIR MASS ALREADY IN PLACE. A STORM SYSTEM WILL MOVE SOUTHEAST
OUT OF BRITISH COLUMBIA, BRINGING AN ABUNDANCE OF MOISTURE WITH
IT.
THE MAIN FORECAST CHALLENGE IS DETERMINING EXACTLY WHEN THE SNOW
WILL DEVELOP. FORECAST SOUNDINGS INDICATES MOISTURE INCREASING
FROM NORTH TO SOUTH DURING THE DAY ON MONDAY. SNOW MAY INITIALLY
FALL DURING THE DAYLIGHT HOURS, BUT IT MAY STRUGGLE TO STICK TO
ROAD SURFACES DUE TO THE SUN'S WARMTH. HOWEVER, IF THE SNOW
ARRIVES EARLIER (SUCH AS IN THE MORNING), ROAD SURFACES COULD
BECOME SLICK, PARTICULARLY ACROSS NORTHWEST MONTANA. HIGH
TEMPERATURES ON MONDAY WILL RANGE FROM THE UPPER 20S IN THE NORTH
TO THE 30S AND 40S OVER IDAHO.
SNOWFALL TOTALS AND LOCATIONS: THIS WEATHER PATTERN FAVORS THE
HEAVIEST SNOW ACCUMULATION ACROSS THE MOUNTAINS AND VALLEYS ALONG
THE MONTANA/IDAHO BORDER, AS WELL AS THE MOUNTAINS OF NORTHWEST
MONTANA. THANKS TO THE COLD AIR TRAPPED IN THE REGION, INTERIOR
VALLEYS ARE LIKELY TO RECEIVE ACCUMULATING SNOW.
- VALLEY SNOWFALL: EXPECT 2 TO 4 INCHES NORTH OF I-90 (LOCALLY
HIGHER AMOUNTS POSSIBLE).
- MOUNTAIN SNOWFALL: EXPECT 4 TO 6 INCHES (EXCLUDING SOUTHWEST
MONTANA).
- HIGH END POTENTIAL: THERE IS A 30% CHANCE OF SNOWFALL
EXCEEDING 8 INCHES IN THE MISSION MOUNTAINS.
SNOW LEVELS WILL REMAIN QUITE LOW ACROSS WESTERN MONTANA,
GENERALLY EXTENDING DOWN TO THE VALLEY FLOORS DUE TO THE LINGERING
COLD AIR MASS. HOWEVER, SOME LOCATIONS IN IDAHO COUNTY COULD SEE
HIGHER SNOW LEVELS, NEARING 3000 FEET.
EXTENDED FORECAST (LATE WEEK): THE PATTERN REMAINS ACTIVE THROUGH
NEXT WEEKEND. THE STRONG HIGH-PRESSURE SYSTEM OVER THE
NORTHEASTERN PACIFIC IS EXPECTED TO WEAKEN SLIGHTLY. IF THIS
OCCURS, THE PACIFIC NORTHWEST AND OUR REGION COULD RECEIVE FLOWS
OF WARM, SUBTROPICAL MOISTURE.
THIS SETS UP A "BATTLEGROUND" FOR TEMPERATURES ACROSS THE REGION.
EXISTING SNOW COVER WILL HELP KEEP COLD AIR TRAPPED IN THE VALLEYS
UNLESS STRONG WINDS SCOUR IT OUT. THE PATH OF THE JET STREAM WILL
DETERMINE WHO SEES WINTRY PRECIPITATION AND WHO SEES RAIN.
CURRENTLY, THE PROBABILITY OF SNOW REMAINING AT VALLEY LEVELS IS
HIGHEST ACROSS NORTHWEST MONTANA NEXT FRIDAY INTO THE WEEKEND.
ELSEWHERE, A WINTRY MIX IS POSSIBLE.
AVIATION
CLEARING SKIES FROM NORTH TO SOUTH, IS EXPECTED TO
BRING A MIX OF PATCHY VALLEY FOG AND STRATUS, PARTICULARLY TO
NORTHWEST MONTANA NORTH OF I-90. WITH THE LACK OF A GRADIENT
TODAY, VALLEY INVERSIONS WILL BE TOUGH TO BREAK, ALLOWING THE FOG
AND STRATUS TO LINGER THROUGH MUCH OF THE DAY, ESPECIALLY NEAR
FLATHEAD LAKE. WIDESPREAD LIGHT TO MODERATE SNOWFALL IS STILL ON
TRACK, WITH THE FIRST ROUND OF MOISTURE ARRIVING MONDAY AFTERNOON
ACROSS NORTHWEST MONTANA AND A SECOND SURGE OF MOISTURE IMPACTING
MUCH OF THE REGION BY TUESDAY MORNING. EXPECT SEVERAL HOURS OF AT
LEAST LIGHT SNOWFALL AT ALL AVIATION SITES IN WESTERN MONTANA INTO
WEDNESDAY MORNING.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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