865
FXUS65 KMSO 210939
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
239 AM MST SAT FEB 21 2026
DISCUSSION
KEY MESSAGES:
- HIGH PRESSURE BUILDS THIS WEEKEND. PATCHY FOG IN THE MORNINGS,
THEN A MIX OF SUN AND CLOUDS.
- WINTRY WEATHER MONDAY IN NORTHWEST MONTANA, SPREADING SOUTH AND
EAST THROUGHOUT THE DAY. IMPACTS WILL BE SNOW ON MOUNTAIN
PASSES AND MIXED PRECIPITATION IN THE VALLEYS
- GUSTY WINDS/ORGANIZED SNOW SHOWERS MID NEXT WEEK
SATELLITE IMAGERY THIS MORNING DEPICTS AN ELONGATED LOW PRESSURE
CIRCULATION OFF THE COAST OF NORTHERN BRITISH COLUMBIA. IN THE
NEAR TERM, THIS FEATURE WILL HELP TO AMPLIFY HIGH PRESSURE TO ITS
SOUTHEAST, INCLUDING THE NORTHERN ROCKIES. WE ARE WELL VERSED ON
HIGH PRESSURE THIS YEAR, SO IT'S NO SURPRISE THAT PATCHY FOG AND
MILD TEMPERATURES ARE IN THE FORECAST THROUGH MONDAY MORNING FOR
MUCH OF THE NORTHERN ROCKIES. DAYTIME HIGH TEMPERATURES WILL START
TO CREEP UP TODAY AND TOP OUT ON SUNDAY OR MONDAY. VALLEYS OF
WESTERN MONTANA WILL SEE UPPER 40S TO LOWER 50S WHILE THE LOWER
SALMON AND CLEARWATER VALLEYS WILL SEE MID TO UPPER 50S.
MODEL GUIDANCE IS IN GOOD AGREEMENT BRINGING THE PACIFIC LOW SOUTH
AND WEST, PUTTING IT OFF THE COAST OF THE PACIFIC NORTHWEST BY
SUNDAY. UPPER LEVEL FLOW FLATTENS OUT ON MONDAY, OPENING THE DOOR
FOR THE LOW TO SEND PACIFIC MOISTURE ONSHORE. WHILE AT FIRST
GLANCE THIS SETUP WOULD RESEMBLE AN ATMOSPHERIC RIVER, WATER VAPOR
TRANSPORT ENSEMBLE MEMBERS ARE SHOWING LOW CHANCES (LESS THAN
30%) FOR MOISTURE AMOUNT AND DURATION TO REACH AR STATUS FOR THE
NORTHERN ROCKIES.
REGARDLESS OF AR STATUS, PRECIPITATION WILL BEGIN EARLY MONDAY
MORNING AND LAST THROUGH TUESDAY. PRECIPITATION TYPE REMAINS THE
PRIMARY UNCERTAINTY. CURRENTLY, NBM SNOW LEVELS APPEAR TOO HIGH
FOR MONDAY MORNING GIVEN THE WARM AIR ADVECTION PATTERN AND
LIMITED MIXING WITH COLD AIR TRAPPED IN THE VALLEYS, SO WE HAVE
TRENDED THESE DOWNWARD. THIS ADJUSTMENT INTRODUCES THE POTENTIAL
FOR LIGHT SNOW IN THE VALLEYS OF NORTHWEST MONTANA EARLY MONDAY.
THEREAFTER, ENHANCED MIXING SHOULD ALLOW SNOW LEVELS TO RISE,
TRANSITIONING VALLEY PRECIPITATION TO A WINTRY MIX, MOST LIKELY
RAIN AND SNOW AT NIGHT, CHANGING TO RAIN DURING THE AFTERNOON
HOURS. OVERALL, PREPARE FOR SLICK PASS-LEVEL ROADS AND POTENTIALLY
MESSY VALLEY ROADS, PRIMARILY DURING THE NIGHTTIME AND MORNING
PERIODS.
THE CHARACTER OF THE EVENT SHIFTS AS AN UPPER-LEVEL TROUGH AND COLD FRONT
PASS THROUGH LATE TUESDAY INTO WEDNESDAY. WESTERLY WINDS WILL INCREASE
ALONGSIDE A THREAT FOR ORGANIZED SNOW SHOWERS AND BANDING. WE WILL BE
WATCHING THIS PERIOD CLOSELY FOR MORE SIGNIFICANT VALLEY IMPACTS.
LOOKING FURTHER AHEAD, GUSTY WINDS ARE EXPECTED THROUGH THE SECOND HALF OF
NEXT WEEK.
AVIATION
A RIDGE OF HIGH PRESSURE THIS WEEKEND WILL BRING A
MIX OF SUN AND CLOUDS, WITH PATCHY FOG EACH MORNING, ESPECIALLY
ACROSS NORTHWEST MONTANA.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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