317
FXUS65 KMSO 120922
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
222 AM MST MON JAN 12 2026
DISCUSSION
KEY MESSAGES:
- LIGHT SNOW AND POCKETS OF FREEZING RAIN ACROSS NORTHWEST
MONTANA, NEAR US-CANADA BORDER THROUGH THIS MORNING.
- HIGH PRESSURE TO BRING PROLONGED DRY PATTERN NEXT 7-10 DAYS
A WEAK DISTURBANCE, ASSOCIATED WITH THE REMNANTS OF AN
ATMOSPHERIC RIVER PRIMARILY IMPACTING CANADA, WILL MOVE THROUGH
NORTHWEST MONTANA THROUGH THIS MORNING. RISING SNOW LEVELS WILL
CAUSE A MIX OF LIGHT SNOW AND FREEZING RAIN. PRECIPITATION WILL
REMAIN LIGHT (TRACE TO 0.02 INCHES), WITH POCKETS OF FREEZING
RAIN IN VALLEYS AREAS OF LINCOLN AND FLATHEAD COUNTIES. COMMUTERS
IN THESE AREAS SHOULD PREPARE FOR LOCALIZED AREAS OF SNOW-COVERED
OR ICY ROADS THIS MORNING. SNOW LEVELS WILL RISE ABOVE 6,000 FEET
THIS AFTERNOON WITH LIGHT SHOWERS AND PRECIPITATION MAINLY
FOCUSING ACROSS THE HIGHER TERRAIN.
A RIDGE OF HIGH PRESSURE WILL MOVE OVER THE NORTHERN ROCKIES FOR
THE REMAINDER OF THE WORK WEEK AND INTO THE WEEKEND. THIS WILL BE
AN ANOMALOUSLY STRONG RIDGE, WITH HEIGHTS (575-580 DAM) REACHING
THE 99TH OR HIGHER PERCENTILE FOR THIS TIME OF YEAR. VALLEY
INVERSIONS ARE EXPECTED TO STRENGTHEN EACH NIGHT, ESPECIALLY BY
WEDNESDAY AND THURSDAY, INCREASING THE RISK FOR FOG AND LOW
STRATUS CLOUDS. A PROLONGED PERIOD OF STAGNANT CONDITIONS IS
EXPECTED FOR VALLEY AREAS, LEADING TO AREAS OF DEGRADING AIR
QUALITY BY MID-LATE WEEK. FUTURE SHIFTS WILL MONITOR THE NEED FOR
AIR STAGNATION ADVISORIES.
GLOBAL ENSEMBLES SUGGEST THIS WILL BE A PROLONGED BLOCKING RIDGE,
WITH MODELS INDICATING A GREATER THAN 65% CHANCE THAT THIS
STAGNANT PATTERN PERSISTS INTO EARLY NEXT WEEK (JANUARY 19-20).
AVIATION
REMNANTS OF AN ATMOSPHERIC RIVER WILL CONTINUE TO STREAM ACROSS
THE NORTHERN ROCKIES THIS MORNING. GOES SATELLITE IMAGERY SHOWS
MID TO HIGH LEVEL CLOUDS MOVING WEST TO EAST. REGIONAL RADAR
IMAGERY HIGHLIGHTS WEAK SHOWER ACTIVITY ACROSS NORTHWEST MONTANA
ALONG THE US-CANADA BORDER OVERNIGHT THROUGH 12/0900Z. COLD
GROUND TEMPERATURES AND AIR TEMPERATURES NEAR FREEZING WILL LEAD
TO LOCALIZED AREAS OF LIGHT FREEZING RAIN ACROSS LINCOLN AND
FLATHEAD COUNTY THROUGH THIS MORNING. THE PROBABILITY OF KGPI
BEING IMPACTED BY PRECIPITATION IS LOW (LESS THAN 30 PERCENT), BUT
SHOWERS ARE ANTICIPATED TO BE IN THE VICINITY OF THE TERMINAL
THROUGH MID MORNING.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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