927
FXUS65 KMSO 150836
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
236 AM MDT WED OCT 15 2025
DISCUSSION
KEY MESSAGES:
- SEASONABLE TEMPERATURES WITH VALLEY RAIN SHOWERS AND LIGHT
MOUNTAIN SNOWFALL TODAY INTO THURSDAY FOR SOUTHWEST MONTANA.
- TRAVEL IMPACTS ARE POSSIBLE OVER MOUNTAIN PASSES EARLY NEXT
WEEK DUE TO SNOWFALL.
A MIX OF CLOUD COVER AND FOG ARE COMMON ACROSS THE REGION THIS
MORNING DUE TO THE LINGERING COOL AIRMASS AND MOISTURE. SHOWERS
WILL AGAIN ENTER THE REGION FROM THE SOUTH TODAY WITH HIGHEST
SHOWER CHANCES ALONG THE DIVIDE. SNOW LEVELS ARE RISING SO THESE
SHOWERS SHOULD PREDOMINATELY BE VALLEY RAIN AND MOUNTAIN SNOW.
HIGH RESOLUTION MODELS ARE TRENDING TOWARD PRECIPITATION SHIFTING
EASTWARD TONIGHT WITH THE MAIN FOCUS BEING EAST OF THE DIVIDE.
LOCATIONS NORTH AND WEST WITH LESS CLOUD COVER AND CALM WINDS HAVE
INCREASED CHANCES FOR AREAS OF VALLEY FOG TO DEVELOP, ESPECIALLY
IN PLACES LIKE THE FLATHEAD AND MISSION VALLEYS.
ON THURSDAY, AN UPPER-LEVEL RIDGE BEGINS TO BUILD OVER THE
REGION, LEADING TO EXPANDING SUNSHINE. HIGH TEMPERATURES ARE
FORECAST TO REBOUND INTO THE UPPER 50S AND LOW 60S FOR MOST VALLEY
LOCATIONS.
THE UPPER-LEVEL PATTERN SHIFTS TO NORTHWESTERLY OF FRIDAY WITH
SHOWERS AND SLIGHTLY BELOW AVERAGE HIGH TEMPERATURES. HEADING INTO
THE WEEKEND, MODEL GUIDANCE NOW INDICATES A BRIEF RIDGE OF HIGH
PRESSURE BUILDING INTO THE REGION WITH MILD TEMPERATURES AND
ISOLATED SHOWERS ON SATURDAY AND SUNDAY BEFORE THE MAIN SYSTEM
ARRIVES LATE SUNDAY INTO MONDAY
THE LATEST NBM GUIDANCE AND ENSEMBLE MODEL DATA CONTINUE TO SHOW
A DEEP AND COLD TROUGH DIGGING SOUTH ALONG THE WEST COAST AND INTO
OUR REGION FROM MONDAY INTO TUESDAY. THERE ARE TIMING AND
STRENGTH DIFFERENCES WITH THIS TROUGH, BUT THERE IS INCREASED
POTENTIAL FOR COOLER TEMPERATURES AND BELOW-AVERAGE SNOW LEVELS.
POTENTIAL IMPACTS FROM THE EARLY WEEK SYSTEM INCLUDE:
- WIDESPREAD PRECIPITATION: WIDESPREAD RAIN IS EXPECTED IN THE
VALLEYS BEGINNING LATE SUNDAY OR MONDAY.
- MOUNTAIN SNOW: SNOW LEVELS ARE FORECAST TO LOWER SIGNIFICANTLY
THROUGH THE DAY ON MONDAY, POTENTIALLY FALLING TO NEAR PASS
LEVELS (4500-5500 FEET). THIS COULD RESULT IN ACCUMULATING SNOW
FOR MOUNTAIN PASSES LIKE LOLO, LOOKOUT, AND MARIAS, LIKELY
CAUSING TRAVEL IMPACTS.
AVIATION
LOW CLOUDS AND FOG HAVE SPREAD OVERNIGHT, FILLING MOST
OF THE VALLEYS THIS MORNING. THIS HAS CREATED MVFR CEILINGS AT
AREA AIRPORTS, A CONDITION THAT WILL LIKELY CONTINUE FOR MOST OF
THE MORNING. SHOWERS ARE ALSO APPROACHING FROM THE SOUTH AND ARE
EXPECTED TO REACH THE CONTINENTAL DIVIDE TODAY, BRINGING REDUCED
VISIBILITY AND OBSCURED MOUNTAIN TERRAIN INTO TONIGHT. AS SKIES
CLEAR BEHIND THE SHOWERS, IT'S POSSIBLE FOR FOG AND LOW CLOUDS TO
REDEVELOP, ESPECIALLY IN NORTH-CENTRAL IDAHO AND NORTHWEST MONTANA
ON THURSDAY MORNING.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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