888
FXUS65 KMSO 251913
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
113 PM MDT SAT OCT 25 2025
DISCUSSION
- BREEZY TODAY WITH GUSTS TO 30-40 MPH IN LEMHI COUNTY AND
SOUTHWEST MONTANA.
- PACIFIC STORM SYSTEM THIS OPENING WEEKEND OF RIFLE SEASON INTO
EARLY NEXT WEEK. THIS WILL BRING WINTER WEATHER CONDITIONS TO
THE MOUNTAINS AND A RAIN/SNOW MIX TO THE VALLEYS.
- PRECIPITATION AMOUNTS CONTINUE TO TREND SLIGHTLY DOWNWARD. THIS
TREND IS LESS NOTICEABLE FOR UP-SLOPE REGIONS OF IDAHO WHERE
SIGNIFICANT PRECIPITATION IS LIKELY.
STRONG WINDS ARE ONE OF THE PRIMARY IMPACTS OF THE ONGOING STORM
TODAY. WHEN COMBINED WITH SOAKING RAINS OR HEAVY, WET SNOW AT HIGH
ELEVATIONS, THERE IS AN INCREASED RISK FOR DOWNED TREES AND
POTENTIAL POWER OUTAGES. THERE IS A 70 TO 90 PERCENT PROBABILITY
THAT GUSTS WILL EXCEED 30 MPH IN THE TERRAIN ALONG AND SOUTH OF
I-90 BY 2 PM THIS AFTERNOON, SPREADING NORTH INTO THE REST OF
WESTERN MONTANA AND NORTH-CENTRAL IDAHO BY 6 PM THIS EVENING.
THOSE TRAVELING IN THE BACKCOUNTRY ABOVE MOUNTAIN PASS LEVELS CAN
EXPECT MODERATE SNOWFALL THROUGH THIS EVENING AS MOISTURE SURGES
IN AHEAD OF A COLD FRONT, CURRENTLY IN CENTRAL WASHINGTON. THE
COLD FRONT WILL ARRIVE IN THE NORTHERN ROCKIES AROUND MIDNIGHT
TONIGHT, BRINGING COLDER TEMPERATURES AND CAUSING SNOW LEVELS TO
CRASH TO AROUND 3,200 FEET BY SUNDAY MORNING. THIS WILL SIGNAL THE
BEGINNING OF WIDESPREAD WINTER DRIVING CONDITIONS OVER MOST
MOUNTAIN PASSES, ESPECIALLY ALONG THE MONTANA-IDAHO BORDER. ANY
ROADS THAT WERE PREVIOUSLY WET MAY BEGIN TO FREEZE RAPIDLY
OVERNIGHT, AND ACCUMULATING SNOW ON ROADS WILL BECOME A CONCERN.
DURING THIS TIME, TREAT SHINY WET ROADS AS IF THEY ARE ICY,
BECAUSE THEY JUST MIGHT BE.
HIGH-RESOLUTION MODELING SUGGESTS LINGERING SHOWERS BEHIND THE
FRONT, WHICH HAVE THE POTENTIAL TO BRING LIGHT SNOWFALL TO THE
VALLEYS OF WEST-CENTRAL MONTANA EARLY TOMORROW MORNING. ANY
ACCUMULATIONS WILL LIKELY BE ON GRASSY AREAS, THOUGH ELEVATED
ROADWAYS MAY SEE ISOLATED SLICK SPOTS. LIGHT TO MODERATE VALLEY
RAIN AND MOUNTAIN SNOW SHOWERS WILL CONTINUE IN A MOIST WESTERLY
FLOW THROUGHOUT THE DAY SUNDAY.
BY SUNDAY NIGHT INTO MONDAY MORNING, A THIRD (YET WEAKER) COLD
FRONT MOVES THROUGH, REINVIGORATING ANOTHER ROUND OF SHOWERS.
TEMPERATURES WILL REMAIN COOL ENOUGH FOR SNOWFLAKES DOWN TO VALLEY
LOCATIONS AROUND 3,000 FEET. NO SIGNIFICANT VALLEY IMPACTS ARE
ANTICIPATED, BUT WE WILL CONTINUE TO MONITOR THE POTENTIAL FOR
ISOLATED SLICK SPOTS DURING THE MONDAY MORNING COMMUTE. TOTAL
SNOWFALL FROM THIS EVENING THROUGH MONDAY MORNING WILL RANGE
BETWEEN 6 TO 10 INCHES ABOVE 5,000 FEET, WITH A 50 PERCENT
PROBABILITY FOR UP TO A FOOT OR MORE ALONG THE BITTERROOT CREST
AND THE MISSION/SWAN RANGES.
FOLLOWING THE WEEKEND'S COLD FRONTS, TEMPERATURES WILL SETTLE
INTO A MUCH COOLER BUT MORE SEASONABLE PATTERN FOR LATE OCTOBER.
MODELING IS ALIGNING ON ANOTHER DISTURBANCE MOVING THROUGH
WEDNESDAY INTO THURSDAY, BRINGING ANOTHER CHANCE FOR SHOWERS.
THE LATE-WEEK AND HALLOWEEN TIME FRAME IS ALSO LOOKING RATHER
STORMY, WITH THE POTENTIAL FOR ANOTHER FETCH OF PACIFIC MOISTURE
PUSHING INLAND.
AVIATION
WIDESPREAD MVFR CONDITIONS, WITH LOCAL IFR, ARE
PRESENT ACROSS NORTH-CENTRAL IDAHO AND ARE EXPANDING ACROSS THE
REMAINDER OF THE REGION THIS AFTERNOON AS A BAND OF RAIN AND
MOUNTAIN SNOW MOVES THROUGH. GUSTY SOUTHERLY WINDS OF 25-35 KTS
ARE ALSO IMPACTING SOME OF THE TERMINALS, ESPECIALLY SOUTH OF I-90
LIKE KSMN AND KBTM. SHOWERY AND BREEZY CONDITIONS WITH WIDESPREAD
MVFR ARE EXPECTED TO CONTINUE THROUGH THIS EVENING AS A COLD
FRONT CROSSES THE AREA. THE BIGGEST CHANGE WILL OCCUR OVERNIGHT AS
MUCH COLDER AIR RUSHES IN, CAUSING SNOW LEVELS TO FALL RAPIDLY TO
AROUND 3,200 FEET BY SUNDAY MORNING. THIS WILL TRANSITION
PRECIPITATION FROM RAIN TO SNOW OVER ALL MOUNTAIN PASSES, CREATING
MOUNTAIN OBSCURATION AND IFR CONDITIONS. BY SUNDAY MORNING, A
RAIN/SNOW MIX WILL BE POSSIBLE IN HIGHER VALLEYS, MAINTAINING
PERIODS OF MVFR/IFR CONDITIONS IN SHOWERS AND LOW CEILINGS.
MSO WATCHES/WARNINGS/ADVISORIES
MT...WINTER WEATHER ADVISORY FROM 3 AM TO 11 AM MDT SUNDAY FOR
BITTERROOT/SAPPHIRE MOUNTAINS...LOWER CLARK FORK REGION...
WEST GLACIER REGION.
WINTER WEATHER ADVISORY FROM 6 PM SUNDAY TO NOON MDT MONDAY FOR
BITTERROOT/SAPPHIRE MOUNTAINS...BUTTE/BLACKFOOT REGION...
KOOTENAI/CABINET REGION...LOWER CLARK FORK REGION...
POTOMAC/SEELEY LAKE REGION...WEST GLACIER REGION.
ID...WINTER WEATHER ADVISORY FROM 2 AM TO 10 AM PDT SUNDAY FOR
NORTHERN CLEARWATER MOUNTAINS...SOUTHERN CLEARWATER
MOUNTAINS.
WINTER WEATHER ADVISORY FROM 6 PM MDT /5 PM PDT/ SUNDAY TO NOON
MDT /11 AM PDT/ MONDAY FOR LOWER HELLS CANYON/SALMON RIVER
REGION...NORTHERN CLEARWATER MOUNTAINS...SOUTHERN
CLEARWATER MOUNTAINS...WESTERN LEMHI COUNTY.
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