403
FXUS65 KMSO 031902
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
102 PM MDT FRI OCT 3 2025
DISCUSSION
KEY MESSAGES:
- SNOW FOR THE HIGHER TERRAIN SATURDAY INTO SUNDAY, ESPECIALLY
AROUND GLACIER NATIONAL PARK.
- WIDESPREAD FROST/FREEZE FOR MONDAY AND TUESDAY MORNINGS.
A STORM SYSTEM IS STILL ON TRACK TO SLIDE SOUTH OUT OF CANADA THIS
WEEKEND, BRINGING OUR FIRST WIDESPREAD MOUNTAIN SNOWFALL TO AREAS
ALONG THE CONTINENTAL DIVIDE, ESPECIALLY GLACIER NATIONAL PARK,
SATURDAY EVENING AND SUNDAY. THE LATEST GUIDANCE SUGGESTS 4 TO 8
INCHES OF SNOWFALL FOR ELEVATIONS ABOVE 5500 FEET IN THE GNP
REGION, WITH A 15 PERCENT PROBABILITY OF ACCUMULATIONS REACHING 10
INCHES AT ELEVATIONS SIMILAR TO LOGAN PASS. SNOW LEVELS ON SUNDAY
MORNING COULD BE AS LOW AS 3000 FEET ALONG HIGHWAY 2 FROM WEST
GLACIER TO MARIAS PASS, WITH AROUND A 60 PERCENT PROBABILITY FOR
UP TO 2 INCHES OF SNOW ON THE PASS ITSELF. ANY SNOW THAT FALLS IN
THE LOWER ELEVATIONS WILL BE LESS THAN AN INCH AND WILL LIKELY
MELT UPON CONTACT WITH ROAD SURFACES.
DUE TO THESE EXPECTED IMPACTS, THE WINTER STORM WATCH HAS BEEN
UPGRADED TO A WINTER STORM WARNING. THOSE WITH PLANS TO RECREATE
IN THE BACKCOUNTRY OF THE GLACIER PARK REGION SHOULD CONSIDER
DELAYING THEIR PLANS.
AS THE FRONT MOVES SOUTH EARLY SUNDAY, SNOW IS ALSO EXPECTED TO
IMPACT THE MOUNTAINS OF THE SEELEY LAKE/POTOMAC REGION, AS WELL AS
THE ANACONDA/PINTLER RANGE; WINTER WEATHER ADVISORIES HAVE BEEN
ISSUED FOR THESE AREAS. PLEASE PACK ADDITIONAL SUPPLIES FOR COLD,
WET, AND BREEZY CONDITIONS IN THE BACKCOUNTRY.
AS THE DISTURBANCE MOVES OUT OF THE AREA LATE SUNDAY INTO MONDAY,
A DRIER AIRMASS WILL SETTLE IN OVER THE REGION. WITH THE
COMBINATION OF CLEAR SKIES AND THIS COLDER AIRMASS, THE FIRST
WIDESPREAD HARD FREEZE IS EXPECTED FOR THE MAJORITY OF THE VALLEYS
OF WESTERN MONTANA. THE LOWER VALLEYS OF IDAHO AND CLEARWATER
COUNTIES ARE EXPECTED TO REMAIN ABOVE FREEZING BUT WILL STILL
LIKELY SEE THEIR FIRST FROST IN AREAS FROM OROFINO TO GRANGEVILLE.
A RIDGE OF HIGH PRESSURE BUILDS OVER THE REGION BY THE MIDDLE OF
NEXT WEEK, ALLOWING FOR A GRADUAL WARMING TREND WITH CHILLY
MORNING LOWS AND SEASONABLE AFTERNOON HIGHS.
AVIATION
A BAND OF LIGHT TO OCCASIONALLY MODERATE RAIN OVER
WEST-CENTRAL MONTANA WILL SLOWLY SHIFT EAST AND DISSIPATE THROUGH
THE EVENING. MOUNTAIN OBSCURATIONS AND LOWERED CEILINGS WILL
CONTINUE TO BE A PROBLEM. PARTIAL CLEARING TONIGHT MAY ALLOW FOR
PATCHY VALLEY FOG BY SATURDAY MORNING BUT OVERALL ENOUGH CLOUD
COVER SHOULD REMAIN TO LIMIT WIDESPREAD FOG DEVELOPMENT. A
DISTURBANCE DROPPING SOUTH FROM BRITISH COLUMBIA WILL OPEN UP THE
POTENTIAL OF SCATTERED LIGHT SHOWERS BEGINNING IN NORTHWEST
MONTANA DURING THE MORNING. SCATTERED LIGHT/MODERATE SHOWERS THEN
EXPAND AREAWIDE IN THE AFTERNOON.
FURTHER CHANGES ARRIVE EARLY SUNDAY AS A BACKDOOR COLD FRONT
INCREASES NORTHEAST WINDS (ESPECIALLY NEAR THE
DIVIDE) AND SHOWER COVERAGE WITH SNOW LEVELS DROPPING TO
4000-5000 FEET.
MSO WATCHES/WARNINGS/ADVISORIES
MT...WINTER STORM WARNING FROM MIDNIGHT SATURDAY NIGHT TO NOON MDT
SUNDAY FOR WEST GLACIER REGION.
WINTER WEATHER ADVISORY FROM MIDNIGHT SATURDAY NIGHT TO NOON MDT
SUNDAY FOR BUTTE/BLACKFOOT REGION...POTOMAC/SEELEY LAKE
REGION.
ID...NONE.
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