918
FXUS65 KMSO 191822
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
1222 PM MDT SAT SEP 19 2026
DISCUSSION
KEY MESSAGES:
- PATCHY FOG EXPECTED SUNDAY MORNING.
- WARM, DRY WEEK AHEAD FOR THE REGION.
- SHOWERS RETURN LATE NEXT WEEK OR EARLY NEXT WEEKEND.
THE RECENT RAINFALL COMBINED WITH DECREASING CLOUD COVER AND
STABLE CONDITIONS THE NEXT FEW DAYS WILL CAUSE PATCHY FOG IN MANY
OF THE VALLEYS OF CENTRAL IDAHO AND WESTERN MONTANA SUNDAY
MORNING. THE FOG IS EXPECTED TO CLEAR OUT BY SUNDAY AFTERNOON DUE
TO DRIER AIR FROM ALOFT MIXING DOWN IN THE AFTERNOON.
AS THE CUTOFF LOW OVER THE REGION MOVES OUT, ANOTHER IS MOVING
INTO THE U.S. WEST COAST AND HEADING SOUTH OF THE DESERT
SOUTHWEST. THERE'S ALSO A BROAD TROUGH ESTABLISHED ACROSS THE
NORTHERN PACIFIC OCEAN. THE TWO FEATURES COMBINED WILL SETUP A
SOUTHWEST, SPLIT FLOW PATTERN INTO THE NORTHERN ROCKIES REGION. AS
A RESULT, THE REGION WILL SEE WARM AND MILD CONDITIONS MOST OF THE
WEEK. AFTERNOON TEMPERATURES WILL BE ABOUT 10 DEGREES ABOVE SEASON
AVERAGES WITH LIGHT WINDS AND PARTLY CLOUDY SKIES.
AS THE BROAD TROUGH OVER THE NORTHERN PACIFIC STARTS TO PROGRESS
EASTWARD, IT WILL START TO BRING SHOWERS BACK TO THE REGION LATE
NEXT WEEK OR EARLY NEXT WEEKEND. WITH THE SOUTHWEST FLOW PATTERN,
THE SNOW LEVELS WILL REMAIN VERY HIGH AND MOUNTAIN SNOW ISN'T A
CONCERN YET, HOWEVER, AS WE GET INTO THE WEEK AFTER IF THE TROUGH
CONTINUES TO PROGRESS EASTWARD IT WOULD BRING SOME COOLER AIR INTO
THE REGION. SO THE BOTTOM LINE IS EXPECT A WARM, MILD WEEK WITH
SOME SHOWERS MOVING IN NEXT WEEKEND AND THE POTENTIAL FOR MORE
MOUNTAIN SNOW A WEEK OR MORE AWAY.
AVIATION
RECENT RAIN FALL COMBINED WITH STABLE CONDITIONS WILL
CAUSE SOME PATCHY FOG ACROSS THE REGION SUNDAY MORNING. TERMINALS
KMSO, KHRF, AND KSMN ARE MOST LIKELY TO BE IMPACTED. SOME PATCHY
FOG NEAR TERMINAL KGPI IS ALSO POSSIBLE DUE TO THE HIGH DEW
POINTS, THOUGH THEY DID NOT RECEIVE ANY PRECIPITATION IN THE LAST
24 HOURS, SO MUCH LESS COVERAGE IS EXPECTED THERE. OTHERWISE, WARM
AND MILD CONDITIONS ARE AHEAD FOR THE NEXT WEEK.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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