706
FXUS65 KMSO 110828
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
228 AM MDT SUN OCT 11 2026
DISCUSSION
KEY MESSAGES:
- COOL, WET WEATHER WITH WINTER STORM ALONG THE CONTINENTAL DIVIDE
CONTINUES THROUGH THE WEEKEND.
- HARD FREEZE IN VALLEYS OF WESTERN MONTANA EARLY THIS WEEK.
- WARMING UP TO ABOVE AVERAGE CONDITIONS IN THE LONG TERM.
THE UPPER LEVEL LOW OVER THE PACIFIC NORTHWEST CONTINUES TO PUMP
MOISTURE UP FROM THE SOUTH WHERE IT INTERACTS WITH A COLD AIR MASS
FROM THE NORTH TODAY. THE MAIN AREA WHERE THE TWO AIR MASSES
COLLIDE IS ALONG THE CONTINENTAL DIVIDE, AND THERE'S A BROAD AREA
OF WINTER STORM WARNINGS AND WINTER WEATHER ADVISORIES MANY MILES
EITHER SIDE OF THE CONTINENTAL DIVIDE AS A RESULT. OVERNIGHT SNOW
STARTED ACCUMULATING ON ROADWAYS IN THE MOUNTAINS AND EVEN SOME
LOWER ELEVATION AREAS LIKE GARRISON JUNCTION. THE FURTHER WEST,
THE WEAKER THE INTERACTION AND THE LESS MOISTURE TO WORK WITH, AND
IN THE VALLEYS OF CENTRAL IDAHO THERE HAS BEEN LITTLE TO NO IMPACT
FROM THIS SYSTEM.
EAST WINDS ALONG THE CONTINENTAL DIVIDE ARE ALSO CAUSING IMPACTS.
AS THE COLD AIR SPILLS OVER THE MOUNTAINS AND ACCELERATES DOWN
HILL IT HAS BEEN CAUSING FREQUENT GUSTS AROUND 40 MPH ON THE EAST
SHORES OF FLATHEAD LAKE AND BADROCK CANYON. THOSE CONDITIONS ARE
EXPECTED TO CONTINUE TODAY, BUT TO A LESSER EXTENT AS THE VALLEYS
OF WESTERN MONTANA START TO FILL UP WITH COLDER AIR.
MUCH COLDER AIR WILL BE IN THE PLACE OVER THE REGION ONCE THE
UPPER LEVEL LOW MOVES OUT OF THE REGION EARLY THIS WEEK. AS A
RESULT, MANY LOCATIONS IN WESTERN MONTANA WILL COOL INTO THE LOW
20S AND A FEW OF THE TYPICALLY COLDER SPOTS DOWN INTO THE TEENS
MONDAY THROUGH WEDNESDAY MORNINGS. IN CENTRAL IDAHO, CONDITIONS
WILL BE MORE MILD WITH VALLEYS COOLING INTO THE 30S AND LOW 40S.
ENSEMBLES STILL AGREE WELL ON A RIDGE BUILDING IN QUICKLY MID TO
LATE NEXT WEEK, AND AS A RESULT BY THE END OF THE WEEK AFTERNOON
TEMPERATURES WILL BE ABOVE AVERAGE AGAIN. HOWEVER, DUE TO A DRIER
AIR MASS IN PLACE AT THAT TIME AND LONGER NIGHTS, WE DO EXPECT
COLD MORNINGS TO CONTINUE THROUGH THE WEEK.
AVIATION
LOW CEILINGS AND POOR VISIBILITY ARE IN THE REGION DUE
TO A STREAM OF MOISTURE FROM THE SOUTH INTERACTING WITH A COLD AIR
MASS FROM THE NORTH OVER OUR REGION. MOST OF THE ACTION IS ALONG
THE CONTINENTAL DIVIDE, AND TERMINAL KBTM WILL BE IMPACTED THE
MOST. OTHER AREA TERMINALS, ESPECIALLY KGPI WILL CONTINUE TO SEE
ELEVATED EAST WINDS THROUGH TODAY. SNOW IS UNLIKELY BUT POSSIBLE
AT KGPI AND KMSO, HOWEVER, LOWER EXPECTED SNOW RATES AND A WARM
GROUND MEAN LITTLE TO NO IMPACT IS EXPECTED AS THE SNOW WILL MELT
QUICKLY ONCE IT FALLS, IF IT FALLS AT THOSE TERMINALS AT ALL.
MOUNTAIN OBSCURATIONS DUE TO THE LOW CLOUD COVER WILL LAST THROUGH
THE WEEKEND.
MSO WATCHES/WARNINGS/ADVISORIES
MT...WINTER WEATHER ADVISORY UNTIL 6 AM MDT MONDAY FOR
BITTERROOT/SAPPHIRE MOUNTAINS...POTOMAC/SEELEY LAKE
REGION...WEST GLACIER REGION.
WIND ADVISORY UNTIL 3 PM MDT THIS AFTERNOON FOR FLATHEAD/MISSION
VALLEYS.
WINTER STORM WARNING UNTIL 6 AM MDT MONDAY FOR BUTTE/BLACKFOOT
REGION.
ID...NONE.
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