476
FXUS65 KMSO 270909
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
209 AM MST SAT DEC 27 2025
DISCUSSION
KEY MESSAGES:
- SATURDAY ARCTIC PUSH: FLASH FREEZE POTENTIAL AS BITTERLY COLD
AIR MOVES WEST OF THE DIVIDE SATURDAY MORNING. STRONG NORTHEAST
WINDS WILL DEVELOP IN PRONE CANYONS AND GAP AREAS (E.G., BAD
ROCK CANYON).
- BUILDING RIDGE (EARLY NEXT WEEK): COLD AND MUCH DRIER CONDITIONS
STARTING SUNDAY.
A FEW LINGERING SHOWERS ARE POSSIBLE TODAY, POTENTIALLY FORMING
BANDS DURING THE AFTERNOON. IMPACTS WILL BE ISOLATED TO THESE
SHOWERS IF THEY DEVELOP AND SHOULD NOT BE LONG LASTING AS THEY
WILL PROPAGATE RAPIDLY SOUTHEASTWARD.
AN ARCTIC BOUNDARY IS STILL ON TRACK TO AFFECT PORTIONS OF
NORTHWEST MT TODAY. IN FACT, AROUND 11:30 PM FRIDAY THE FIRST
HINTS OF ARCTIC AIR CAN BE SEEN IN WEATHER STATIONS JUST NORTH OF
CUT BANK, MT WHERE WINDS TURNED NORTHERLY. ITS 'PICK YOUR FAVORITE
WEATHER MODEL FRIDAY' ON TIMING OF THE FRONT BUT A MIDDLE OF THE
ROAD TIMING WOULD BE:
6 AM - 9 AM MARIAS PASS
10 AM - 2 PM KALISPELL MT
1 PM - 5 PM LINCOLN MT
SUNDAY MORNING LOW PROBABILITY OF REACHING MISSOULA AND
BITTERROOT VALLEYS
THERE IS DECENT CONFIDENCE THAT US-2 FROM MARIAS PASS INTO THE
FLATHEAD VALLEY WILL HAVE ARCTIC FRONT IMPACTS SUCH AS GAP WINDS
UP TO 40 MPH, RAPIDLY DROPPING TEMPERATURES, ENHANCED SNOWFALL
RATES, AND POTENTIAL FOR WET ROADS TO FREEZE UP. ELSEWHERE, THE
ONLY EFFECTS FROM THE ARCTIC MAY BE THE COLDEST TEMPERATURES YET
THIS SEASON. FOR INSTANCE, THE COLDEST TEMPERATURE YET THIS SEASON
FOR MISSOULA HAS BEEN 17F ON NOV 30TH. THERE IS A 50/50 CHANCE
THE LOW TEMPERATURE WILL BE BELOW 10F ON SUNDAY IN MISSOULA.
NORTH AND EAST OF MISSOULA, EXPECT LOWS OF SINGLE DIGITS ABOVE
ZERO. CONTINUED WINDS AND CLOUD COVER WILL LIKELY INHIBIT
TEMPERATURES FROM LOWERING BELOW ZERO EXCEPT IN HIGHER ELEVATIONS.
NOW COMES THE DIFFICULT PART OF THE FORECAST, A RIDGE WILL DEVELOP
OVER THE REGION ON SUNDAY. QUESTION IS HOW DOES THE RIDGE OF HIGH
PRESSURE PLAY OUT? VALLEY LOCATIONS THAT RECEIVE A FEW INCHES OF
SNOW BY THIS EVENING, MAY QUICKLY DEVELOP COLD POOLS. THESE
LOCATIONS COULD SEE EFFECTS SUCH AS HIGH TEMPERATURES REMAINING IN
THE UPPER 20S FOR A FEW DAYS, WITH LOW STRATUS OR FREEZING FOG
FOR MOST OF THE MORNINGS. IN VALLEYS THAT DO NOT RECEIVE A FEW
INCHES OF SNOW, CONDITIONS WILL TAKE LONGER TO DEVELOP. OVER A FEW
DAYS THESE LOCATIONS WILL EXPERIENCE EXPANDING AREAS OF MORNING
FOG OR LOW STRATUS, THAT LASTS LONGER EACH DAY. HIGH TEMPERATURES
THAT QUICKLY RECOVER INTO THE UPPER 30S SUNDAY, MAY SLOWLY LOWER
INTO LOWER 30S. IT WILL BE ALL ABOUT WHO GETS A FEW INCHES OF SNOW
OR NOT.
HIGH PRESSURE IS EXPECTED TO LAST THROUGH THE END OF THE COMING WORK
WEEK. THIS LOOKS TO BE A DIRTY RIDGE, SO THERE WILL BE TIMES WITH
MOISTURE MOVING THROUGH THE RIDGE PRODUCING CLOUDS WITH LOW
PROBABILITY OF ANY PRECIPITATION BEYOND A FEW LIGHT SHOWERS IN THE
MOUNTAINS NORTH OF I-90.
AVIATION
AN ARCTIC BOUNDARY IS STILL FORECAST TO IMPACT KGPI
BETWEEN 27/1600 AND 27/1900Z. EXPECT WINDS TO SWING NORTHEASTERLY
WITH GUSTS 25 TO 30 KTS. A BRIEF PERIOD OF SNOW IS POSSIBLE WITH
THE FRONT, TEMPORARILY LOWERING VISIBILITY AND CEILINGS.
ELSEWHERE, ISOLATED SHOWERS ARE EXPECTED DURING THE AFTERNOON,
THEY WILL ALSO BE CAPABLE OF BRIEFLY LOWERING VISIBILITY AND
CEILINGS.
MSO WATCHES/WARNINGS/ADVISORIES
MT...WINTER WEATHER ADVISORY UNTIL 2 PM MST SATURDAY FOR LOWER CLARK
FORK REGION.
WINTER WEATHER ADVISORY UNTIL 8 PM MST SATURDAY FOR
BITTERROOT/SAPPHIRE MOUNTAINS...FLATHEAD/MISSION VALLEYS...
POTOMAC/SEELEY LAKE REGION.
WINTER WEATHER ADVISORY UNTIL 5 PM MST SATURDAY FOR
KOOTENAI/CABINET REGION...WEST GLACIER REGION.
WINTER WEATHER ADVISORY UNTIL 5 PM MST SATURDAY FOR
MISSOULA/BITTERROOT VALLEYS.
WIND ADVISORY UNTIL 5 AM MST SATURDAY FOR BUTTE/BLACKFOOT REGION.
WINTER WEATHER ADVISORY FROM 5 AM TO 8 PM MST SATURDAY FOR
BUTTE/BLACKFOOT REGION.
WIND ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR POTOMAC/SEELEY LAKE
REGION.
ID...WINTER WEATHER ADVISORY UNTIL 1 PM PST SATURDAY FOR NORTHERN
CLEARWATER MOUNTAINS.
WINTER WEATHER ADVISORY UNTIL 8 PM MST /7 PM PST/ SATURDAY FOR
EASTERN LEMHI COUNTY...SOUTHERN CLEARWATER MOUNTAINS...
WESTERN LEMHI COUNTY.
WINTER WEATHER ADVISORY UNTIL 10 AM PST SATURDAY FOR
OROFINO/GRANGEVILLE REGION.
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