050
FXUS65 KMSO 142008
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
208 PM MDT MON SEP 14 2026
DISCUSSION
KEY MESSAGES:
- AREAS OF FROST ON TUESDAY MORNING.
- DRYING AND WARMING CONDITIONS BY MID-WEEK.
- TRENDING WETTER LATE THURSDAY INTO FRIDAY.
AN UPPER-LEVEL LOW CONTINUES TO TRACK EAST TOWARD THE NORTHERN
PLAINS, LEAVING LINGERING MOUNTAIN TERRAIN SHOWERS ALONG THE
CONTINENTAL DIVIDE. SCATTERED SNOW SHOWERS WILL CONTINUE FOR LOGAN
PASS IN GLACIER NP INTO THIS EVENING LEADING TO SLUSHY CONDITIONS
AT TIMES. WESTERLY WINDS GUSTING TO 20-25 MPH WILL DIMINISH NEAR
SUNSET, YIELDING A COOL, AUTUMNAL AFTERNOON.
CLOUDS WILL PERSIST ACROSS NORTHWEST MONTANA TONIGHT, BUT
CLEARING SKIES SOUTH OF INTERSTATE 90 WILL CREATE OPTIMAL
CONDITIONS FOR RADIATIONAL COOLING BY EARLY TUESDAY. AREAS OF
FROST ARE EXPECTED IN THE HIGHER VALLEYS ALONG THE DIVIDE AND
NORTH- CENTRAL IDAHO, AS WELL AS COLD-PRONE SPOTS WITHIN THE
MISSOULA, BITTERROOT, AND CLEARWATER VALLEYS. PROTECT SENSITIVE
VEGETATION.
SCATTERED SHOWERS REMAIN CONFINED NEAR THE CANADIAN BORDER ON
TUESDAY WITH PERIODIC MID- TO HIGH-LEVEL CLOUDINESS ELSEWHERE.
DAYTIME TEMPERATURES WILL GRADUALLY WARM BACK TO SEASONAL AVERAGES
THROUGH WEDNESDAY.
A WETTER PATTERN RETURNS THURSDAY INTO FRIDAY AS ANOTHER UPPER-
LEVEL TROUGH SLOWLY TRAVERSES THE NORTHERN ROCKIES. DEEP
SOUTHWESTERLY FLOW WILL ADVECT MONSOONAL MOISTURE INTO THE REGION,
ELEVATING PRECIPITABLE WATER (PWAT) VALUES TO 150-200% OF NORMAL.
WEAK BULK SHEAR WILL LIMIT ORGANIZED SEVERE WEATHER, BUT DIURNAL
HEATING WILL GENERATE MODEST INSTABILITY FOR SCATTERED
THUNDERSTORMS. WEAK STEERING CURRENTS AND HIGH PWATS MAKE SLOW-
MOVING THUNDERSTORMS CONTAINING LOCALLY HEAVY RAINFALL AND
LOCALIZED RUNOFF THE PRIMARY HAZARDS.
ENSEMBLE GUIDANCE AGREES WELL (90%) ON A WARMING AND DRYING TREND
FROM SATURDAY THROUGH NEXT MONDAY.
AVIATION
PERSISTENT SHOWERS ARE EXPECTED ACROSS WESTERN MONTANA
THROUGH THE EARLY EVENING HOURS. CLOUD COVER WILL GRADUALLY
DIMINISH TONIGHT FOR MOST AREAS EXCEPT NORTHWEST MONTANA. AN
INCREASING PRESSURE GRADIENT WILL PROMOTE BREEZY WESTERLY SURFACE
WINDS ACROSS WESTERN MONTANA THIS AFTERNOON, PRODUCING GUSTS OF 15
TO 25 KTS, EXCEPT CLOSER TO 30 KTS OVER THE DIVIDE. FOR TUESDAY,
THERE COULD BE PATCHES OF VALLEY FOG OVER NORTH-CENTRAL IDAHO AND
WEST-CENTRAL/SOUTHWESTERN MONTANA IN THE MORNING GIVING WAY TO
PARTLY CLOUDY SKIES AND VFR CONDITIONS. A NORTHERLY WIND GRADIENT
MAY HELP TO ENHANCE THE EARLY EVENING NORTH WINDS AT KMSO, AND
KGPI MAY EXPERIENCE MORE VARIABLE WIND RATHER THAN THE TYPICAL
SOUTHERLY LAKE BREEZE.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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