175
FXUS65 KMSO 090949
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
349 AM MDT FRI OCT 9 2026
DISCUSSION
KEY MESSAGES:
- GUSTY WEST WINDS FRIDAY AFTERNOON WILL CREATE CRITICAL FIRE
WEATHER CONDITIONS ACROSS SOUTHWEST MONTANA, CHOPPY CONDITIONS
AT AREA LAKES, AND HAZARDOUS CROSSWINDS FOR HIGH- PROFILE
VEHICLES ON I-90 FROM DEER LODGE TO BUTTE, AND I-15 SOUTH OF
BUTTE.
- STRONG NORTHEAST WINDS WILL DEVELOP SATURDAY, CAUSING CHOPPY
WAVES THAT COULD POSE A DANGER TO DOCKS AND BOATS ON THE
SOUTHWESTERN PORTION OF FLATHEAD LAKE. ISOLATED POWER OUTAGES
ARE POSSIBLE ACROSS NORTHWEST MONTANA THROUGH SATURDAY NIGHT.
- THE FIRST WINTER STORM OF THE SEASON IS EXPECTED TO BRING WET,
HEAVY SNOW, COLD TEMPERATURES, AND GUSTY NORTHEAST WINDS TO THE
MOUNTAINS AND HIGH VALLEYS OF WEST-CENTRAL, SOUTHWEST, AND
CENTRAL MONTANA LATE SATURDAY THROUGH SUNDAY NIGHT. THIS HEAVY
SNOW COULD DAMAGE TREES AND POWER LINES, AND WILL SIGNIFICANTLY
IMPACT BACKCOUNTRY RECREATION, HUNTERS, AND TRAVEL.
IT BE A BREEZY DAY ACROSS THE NORTHERN ROCKIES. SOUTHWEST WINDS
WILL INCREASE TO 15 TO 25 MPH, BRINGING A 1 TO 2 FOOT CHOP TO
FLATHEAD LAKE. STRONGER WINDS OF 20 TO 30 MPH WITH GUSTS UP TO 45
MPH ARE POSSIBLE FROM LEMHI COUNTY TO SOUTHWEST MONTANA. IN
ADDITION TO DANGEROUS CROSSWINDS ON NORTH-SOUTH HIGHWAYS, THE DRY
AND WINDY CONDITIONS WILL CREATE CRITICAL FIRE WEATHER CONDITIONS
ACROSS SOUTHWEST MONTANA.
ON SATURDAY, AS A LOW PRESSURE SYSTEM MOVES ONSHORE OVER WASHINGTON AND
OREGON, NORTHEAST WINDS WILL INCREASE ACROSS MUCH OF THE REGION. AT THE
SAME TIME, COLD, BELOW-FREEZING AIR WILL PUSH SOUTH FROM ALBERTA, CANADA,
FURTHER INCREASING THE NORTHEAST WINDS. FLATHEAD LAKE WILL AGAIN EXPERIENCE
CHOPPY CONDITIONS, BUT FROM THE NORTHEAST BY SATURDAY AFTERNOON. NORTHEAST
WINDS OF 15 TO 25 MPH WITH GUSTS TO 35 MPH COULD POSE A DANGER TO DOCKS AND
BOATS FROM YELLOW BAY SOUTH AND WEST TOWARD THE NARROWS AND BIG ARM.
MOISTURE WRAPPING AROUND THE LOW PRESSURE SYSTEM OVER OREGON WILL MOVE OVER
THE COLD AIR PUSHING SOUTH ACROSS WESTERN MONTANA SATURDAY NIGHT. SNOW
LEVELS WILL FALL TO THE VALLEY FLOORS ALONG AND WEST OF THE DIVIDE. THE
COLD AIR WILL WEAKEN AS IT REACHES THE IDAHO/MONTANA BORDER, SO SNOW LEVELS
IN CENTRAL IDAHO WILL REMAIN HIGHER, GENERALLY ABOVE 4000 FEET.
TEMPERATURES FALLING INTO THE 20S AT MACDONALD PASS, COMBINED WITH GUSTY
NORTHEAST WINDS AND WET, HEAVY SNOW, WILL OVERCOME THE WARM GROUND AND MAKE
TRAVEL CONDITIONS SLICK. THIS WET, HEAVY SNOW MAY ALSO CAUSE IMPACTS TO
POWER LINES AND TREES. OTHER LOCATIONS, INCLUDING GEORGETOWN LAKE, BUTTE,
AND HOMESTAKE PASS, COULD ALSO EXPERIENCE WINTER-LIKE CONDITIONS. THE
HIGHEST PROBABILITIES FOR 3 INCHES OF SNOW OR GREATER EXIST IN
THESE AREAS.
THE HEAVIEST PRECIPITATION WILL BE WITH A NARROW BAND THAT IS CURRENTLY
FORECAST TO BE OVER THE ANACONDA/PINTLER RANGE AND SPREADING EAST OVER
HOMESTAKE AND MACDONALD PASSES. IF THIS BAND WERE TO SHIFT FURTHER NORTH,
AREAS AROUND SEELEY LAKE AND THE BOB MARSHALL WILDERNESS COULD SEE A HIGHER
IMPACT, WHICH WOULD ALSO ALLOW RAIN TO CHANGE OVER TO SNOW IN PLACES LIKE
MISSOULA. HOWEVER, IMPACTS SHOULD BE MINIMAL IN THE LOWER ELEVATIONS, ASIDE
FROM THE CHILL.
A WINTER STORM WATCH IS CURRENTLY VALID FOR AREAS ENCOMPASSING
HOMESTAKE AND MACDONALD PASSES AND THE GEORGETOWN LAKE AREA NEAR
THE ANACONDA/PINTLER RANGES. LOWER ELEVATIONS, INCLUDING BUTTE AND
ANACONDA, WILL ALSO SEE ACCUMULATING SNOW, THOUGH TO A LESSER
EXTENT. THERE ARE WINTER WEATHER ADVISORIES OUT FOR THE MOUNTAINS
NORTH AND WEST OF THIS REGION, INCLUDING THE BITTERROOT AND
SAPPHIRE RANGES AND THE SEELEY-SWAN REGION.
ON SUNDAY, SUBTROPICAL MOISTURE FROM THE REMNANTS OF HURRICANE
RACHEL (WHICH IS CURRENTLY SITUATED SOUTHWEST OF THE BAJA
CALIFORNIA) IS STILL ON TRACK TO MOVE NORTHWARDS TOWARDS THE
YELLOWSTONE AND WYOMING AREAS. THE ENSEMBLE WEATHER MODELING
SYSTEMS ARE STILL DIVIDED IN HOW THE UPPER LOW WILL EVOLVE LATER
SUNDAY INTO SUNDAY NIGHT. THIS IS A KEY FEATURE THAT DECIDE HOW
FAR NORTH AND WEST THE MOISTURE WILL ADVECT. WE CONTINUE TO BE ON
THE EDGE OF IT, WITH LINGERING SNOW POSSIBLE SUNDAY INTO SUNDAY
NIGHT.
AS THE WEATHER SYSTEM PULLS AWAY, MONDAY MAY BRING THE FIRST WIDESPREAD
HARD FREEZE OF THE SEASON. WESTERN MONTANA MAY SEE LOWS IN THE UPPER TEENS
TO LOW 20S, WHILE THE LOWER ELEVATIONS IN NORTH-CENTRAL IDAHO GET CLOSE TO
FREEZING.
AVIATION
A DRY COLD FRONT WILL BRING GUSTY WEST TO SOUTHWEST
WINDS TODAY. TERMINALS GPI, MSO, AND BTM MAY EXPERIENCE THE
STRONGEST GUSTS BETWEEN 25 AND 35 KNOTS. GUSTY NORTHEAST WINDS
WILL DEVELOP ON SATURDAY. A WINTER STORM WILL BRING LOW CEILINGS,
VISIBILITY AND SNOW ALONG THE DIVIDE AND POINTS WEST SATURDAY
NIGHT THROUGH SUNDAY NIGHT.
MSO WATCHES/WARNINGS/ADVISORIES
MT...LAKE WIND ADVISORY FROM NOON TODAY TO 9 PM MDT THIS EVENING FOR
FLATHEAD/MISSION VALLEYS.
WINTER WEATHER ADVISORY FROM 6 PM SATURDAY TO 6 PM MDT SUNDAY
FOR BITTERROOT/SAPPHIRE MOUNTAINS...POTOMAC/SEELEY LAKE
REGION.
WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY
AFTERNOON FOR BUTTE/BLACKFOOT REGION.
ID...NONE.
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