872
FXUS65 KMSO 250846
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
246 AM MDT SAT OCT 25 2025
DISCUSSION
KEY MESSAGES:
- 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.
WINDS ARE ONE OF THE PRIMARY IMPACTS OF THE ONGOING STORM AND WILL
CONTINUE THROUGH 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. THESE STRONG WINDS WILL ALSO
HELP FREEZE WET ROADS FASTER ONCE COLDER AIR ARRIVES.
A COLD FRONT ARRIVES THIS EVENING. IT WILL BRING A CHANCE FOR
BRIEF HEAVY SHOWERS AND THUNDERSTORMS, ALONG WITH GUSTY OUTFLOW
WINDS, AS IT TRACKS WEST TO EAST. THIS FRONT WILL BRING MUCH
COLDER TEMPERATURES AND CRASHING SNOW LEVELS, DROPPING THEM TO
ABOUT 4,000 FEET.
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.
LIGHT VALLEY RAIN AND MOUNTAIN SNOW SHOWERS WILL CONTINUE IN A
MOIST AND COOL WESTERLY FLOW THROUGH SUNDAY. BY SUNDAY NIGHT INTO
MONDAY MORNING, A THIRD (YET WEAKER) COLD FRONT MOVES THROUGH,
REINVIGORATING ANOTHER ROUND OF SHOWERS. AT THIS TIME,
TEMPERATURES MAY COOL ENOUGH TO MIX SNOWFLAKES DOWN TO VALLEY
LOCATIONS ABOVE 3,000 FT. NO SIGNIFICANT VALLEY IMPACTS ARE
ANTICIPATED, BUT WE WILL CONTINUE TO MONITOR THE POTENTIAL FOR
ISOLATED SLICK SPOTS DURING THE MONDAY MORNING COMMUTE.
THE MOST SIGNIFICANT CHANGE TO THE FORECAST HAS BEEN THE CONTINUAL
DOWNTREND IN PRECIPITATION AMOUNTS. THE ONE AREA HOLDING ON TO
SIGNIFICANT PRECIPITATION IS THE UP-SLOPE-FAVORED REGION OF NORTH-
CENTRAL IDAHO, WHERE 0.5-1.5 INCHES OF RAIN (BELOW 6,000 FT) IS
STILL ANTICIPATED.
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 / HALLOWEEN TIME FRAME IS ALSO LOOKING RATHER
STORMY, WITH THE POTENTIAL FOR ANOTHER FETCH OF PACIFIC MOISTURE
PUSHING INLAND.
AVIATION
EXPECT MVFR CONDITIONS WITH LOCAL IFR ACROSS NORTH-
CENTRAL IDAHO DUE TO STEADY RAIN AND LOWER CEILINGS THIS MORNING.
VALLEY WINDS ARE EXPECTED TO PICK UP AGAIN LATE MORNING THIS
MORNING FOR AREAS MAINLY SOUTH OF I-90 WITH GUSTS TO 25-35 KTS AT
KSMN AND KBTM. SHOWER COVERAGE EXPANDS AREAWIDE ON SATURDAY
AFTERNOON AND EVENING WITH ACCOMPANYING LOWERED CEILINGS AND
REDUCED VISIBILITY.
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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