262
FXUS65 KMSO 081039
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
439 AM MDT THU OCT 8 2026
DISCUSSION
KEY MESSAGES:
- GUSTY WEST WINDS FRIDAY AFTERNOON CREATING NEAR-CRITICAL FIRE
WEATHER CONDITIONS ACROSS SOUTHWEST MONTANA, CHOPPY CONDITIONS
AT AREA LAKES, AND HAZARDOUS CONDITIONS FOR EMPTY, HIGH-PROFILE
VEHICLES ON I-90 DEER LODGE TO BUTTE, AND I-15 SOUTH OF BUTTE.
- STRONG NORTHEAST WINDS 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 IS EXPECTED TO BRING SNOW, COLD
TEMPERATURES AND GUSTY NORTHEAST WINDS TO THE MOUNTAINS AND HIGH
VALLEYS FROM WEST- CENTRAL TO SOUTHWEST AND CENTRAL MONTANA LATE
SATURDAY THROUGH SUNDAY AND SUNDAY NIGHT. THIS COULD HIGHLY
IMPACT BACKCOUNTRY RECREATION, HUNTERS AND TRAVEL.
TODAY AND TOMORROW WILL BE THE LAST SUMMER-LIKE DAYS FOR US FOR A
WHILE. ON FRIDAY, A RELATIVELY DRY COLD FRONT WILL MOVE ACROSS THE
REGION. THE WESTERLY WIND GRADIENT WILL TIGHTEN AND SOUTHWEST
WINDS OF 15 TO 25 MPH WILL BRING A 1 TO 2 FOOT CHOP ON FLATHEAD
LAKE. STRONGER WINDS OF 20 TO 30 MPH WITH GUSTS TO 45 MPH ARE
POSSIBLE FROM LEMHI COUNTY TO SOUTHWEST MONTANA. BESIDES THE
DANGERS OF CROSS-WINDS ON NORTH-SOUTH HIGHWAYS, THE COMBINATION OF
DRY AND WINDY CONDITIONS WILL CREATE NEAR-CRITICAL FIRE WEATHER
CONDITIONS ACROSS SOUTHWEST MONTANA.
ON SATURDAY, AS A LOW PRESSURE SYSTEM MOVES ONSHORE OVER
WASHINGTON AND OREGON, A NORTHEAST WIND GRADIENT WILL DEVELOP
ACROSS MUCH OF THE REGION. AT THE SAME TIME, A COLD, SUB-
FREEZING AIRMASS WILL PUSH SOUTH OUT OF ALBERTA CANADA WHICH WILL
ENHANCE THE NORTHEAST WINDS EVEN MORE. FLATHEAD LAKE WILL AGAIN
EXPERIENCE CHOPPY CONDITIONS, BUT FROM THE OPPOSITE DIRECTION
(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 TOWARDS THE NARROWS AND BIG
ARM. THE LAKE IS AT 2,892.52 FEET WHICH IS 0.48 FEET BELOW FULL
POOL.
MOISTURE WRAPPING AROUND THE TROF OVER OREGON WILL OVERRUN THE
COLD AIR THAT WILL BE PUSHING SOUTHWARDS ACROSS WESTERN MONTANA
SATURDAY NIGHT. SNOW LEVELS WILL BE FALLING TO VALLEY FLOORS ALONG
AND WEST OF THE DIVIDE. THE COLD AIR WILL START TO LOSE STEAM AS
IT BANKS UP AGAINST THE IDAHO/MONTANA BORDER, SO SNOW LEVELS IN
CENTRAL IDAHO WILL BE HIGHER GENERALLY 3000 TO 4000 FEET.
TEMPERATURES FALLING INTO THE 20S AT MACDONALD PASS, COMBINED WITH
GUSTY NORTHEAST WINDS AND SNOW WILL BE ENOUGH TO OVERCOME THE
WARM GROUND AND COULD MAKE TRAVEL CONDITIONS SLICK. 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. DEPENDING ON HOW FAR NORTH THE MOISTURE TRAVELS, EVEN RAIN
COULD CHANGEOVER TO SNOW FOR PLACES LIKE MISSOULA BUT MAY BE
MINIMAL IMPACT COME SUNDAY MORNING EXCEPT FOR THE CHILL IN THE
AIR! THIS IS A VERY RARE CIRCUMSTANCE, BUT MOISTURE FROM THE
REMNANTS OF HURRICANE RACHEL WILL TRACK NORTHEASTWARDS FROM
CALIFORNIA AND NEVADA TOWARDS THE YELLOWSTONE AND WYOMING AREA.
WE'LL BE JUST ON THE EDGE OF FURTHER MOISTURE AND LINGERING SNOW
LATER SUNDAY INTO SUNDAY NIGHT...I.E. BUTTE AND HOMESTAKE PASS ON
I-90 MAY HOLD ON TO SNOW SUNDAY NIGHT!
AS THE WEATHER SYSTEM PULLS AWAY ON MONDAY, HIGH TEMPERATURES
WILL BE 5 TO 8 DEGREES BELOW AVERAGE.
AVIATION
VFR CONDITIONS WILL CONTINUE ACROSS THE NORTHERN
ROCKIES TERMINALS THROUGH TODAY UNDER HIGH PRESSURE. LIGHT
TERRAIN DRIVEN WINDS AND MOSTLY CLEAR SKIES ARE EXPECTED, WITH
PASSING HIGH CLOUDS. STRONG VALLEY INVERSIONS WILL PROMOTE THE
DEVELOPMENT OF LOCALIZED MORNING MIST/FOG NEAR BODIES OF WATER,
INCLUDING AREA RIVERS AND LAKES. A DRY COLD FRONT WILL BRING GUSTY
WEST TO SOUTHWEST WINDS ON FRIDAY. TERMINALS GPI AND BTM MAY
EXPERIENCE THE STRONGEST GUSTS BETWEEN 25 AND 35 KNOTS.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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