650
FXUS65 KMSO 242048
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
248 PM MDT FRI OCT 24 2025
DISCUSSION
KEY MESSAGES:
- BREEZY THIS AFTERNOON THROUGH SATURDAY. STRONG GUSTS TO 40-45
MPH IN THE CAMAS PRAIRIE OF IDAHO THIS AFTERNOON/EVENING. GUSTS
TO 30-40 MPH IN LEMHI COUNTY AND SOUTHWEST MONTANA ON
SATURDAY.
- 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 UPSLOPE REGIONS OF IDAHO WHERE
SIGNIFICANT PRECIPITATION IS LIKELY.
SOUTHWEST WINDS WILL STRENGTHEN TODAY, PEAKING THIS EVENING. GUSTS
OF 40-45 MPH ARE HIGHLY LIKELY (80%+) IN THE CAMAS PRAIRIE,
ESPECIALLY IN LOCATIONS LIKE GRANGEVILLE. ELSEWHERE, EXPECT
WIDESPREAD GUSTS OF 20-35 MPH, STRONGEST IN THE HIGHER TERRAIN.
THESE WINDS ARE ONE OF THE PRIMARY IMPACTS OF THIS STORM AND WILL
CONTINUE THROUGH SATURDAY. 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.
THE FIRST COLD FRONT WILL MOVE THROUGH THE REGION AROUND MIDNIGHT
TONIGHT, BRINGING THE FIRST ROUND OF SHOWERS TO NORTH-CENTRAL
IDAHO. SHOWERS COULD BE MODERATE AT TIMES (UP TO 0.10" PER HOUR)
FROM THE US-95 CORRIDOR NORTHEAST INTO CLEARWATER COUNTY. THE
HIGHER TERRAIN OF NORTHWEST MONTANA WILL ALSO SEE LIGHT
PRECIPITATION, WITH SNOW LEVELS BETWEEN 6,000 AND 7,000 FEET.
THE SECOND, AND MORE VIGOROUS, COLD FRONT ARRIVES AFTER 5 PM ON
SATURDAY. 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 UPSLOPE-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 TIMEFRAME IS ALSO LOOKING RATHER STORMY,
WITH THE POTENTIAL FOR ANOTHER FETCH OF PACIFIC MOISTURE PUSHING
INLAND.
AVIATION
VFR FLYING, ALONG WITH MILD AND DRY CONDITIONS ARE EXPECTED
THROUGH THIS AFTERNOON AS THE REGION WILL BE UNDER GENERAL
RIDGING, WHICH WILL BREAK DOWN BY THIS EVENING. GUSTY SOUTH WINDS
OVER 30 KNOTS WILL DEVELOP BY 5 PM PDT THIS EVENING IN THE CAMAS
PRAIRIE, IDAHO. LOW LEVEL WIND SHEAR AT GRANGEVILLE COULD APPROACH
45 KNOTS AT 1500 FEET AGL THROUGH 11 PM PDT FRIDAY. SOUTHWEST
WINDS WILL INCREASE OVER THE CONTINENTAL DIVIDE IN THE GLACIER
REGION TONIGHT INTO SATURDAY. THIS COULD INDUCE MOUNTAIN WAVE
ACTIVITY.
BY SATURDAY MORNING, CONDITIONS WILL DETERIORATE TO MVFR WITH
LOCAL IFR ACROSS NORTH-CENTRAL IDAHO DUE TO STEADY RAIN AND LOWER
CEILINGS. VALLEY WINDS ARE EXPECTED TO PICK UP AGAIN LATE MORNING
ON SATURDAY 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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