389
FXUS65 KMSO 030914
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
214 AM MST WED DEC 3 2025
DISCUSSION
KEY MESSAGES:
- SLICK TRAVEL CONTINUES: STRATUS AND FOG WILL CAUSE PERIODS OF
SLOW DRIVING CONDITIONS THIS MORNING.
- MID-WEEK LULL: A BRIEF BREAK IN WIDESPREAD PRECIPITATION IS
EXPECTED TODAY, THOUGH STABLE AIR MAY TRAP LOW CLOUDS AND
FREEZING FOG IN THE VALLEYS.
- COMPLEX LATE WEEK STORM: AN ACTIVE PATTERN RESUMES THURSDAY INTO
THIS WEEKEND WITH A POTENT MOISTURE SURGE. THERE IS SIGNIFICANT
UNCERTAINTY REGARDING VALLEY SNOW LEVELS, WHICH WILL DETERMINE
WHETHER IMPACTFUL SNOW OR A WINTRY MIX OCCURS IN LOWER
ELEVATIONS.
CURRENT SATELLITE AND RADAR IMAGERY SHOW THE BACK EDGE OF OUR
RECENT STORM SYSTEM SLOWLY MOVING EAST INTO CENTRAL MONTANA.
WHILE MOST OF THE SNOWFALL HAS ENDED, LIGHT SNOW SHOWERS WILL BE
POSSIBLE IN THE MOUNTAINS ACROSS NORTHWEST MONTANA THIS AFTERNOON
AND AREAS OF FREEZING FOG CREATING LINGERING SLICK SURFACES IN THE
VALLEYS.
OUR NEXT WEATHER SYSTEM ARRIVES TOMORROW AND WILL BE THE START OF
A MULTI-DAY EVENT, LASTING THROUGH THIS WEEKEND. THE CRITICAL
FORECAST CHALLENGE WILL BE THE "BATTLEGROUND" BETWEEN THE COOL AIR
CURRENTLY IN THE VALLEYS AND THE INCOMING MILDER AIR ALOFT.
LATEST MODEL GUIDANCE HAS TRENDED SLIGHTLY COOLER COMPARED TO
PREVIOUS RUNS THE PAST 24 TO 48 HOURS. WE EXPECT A PERIOD OF SNOW
AS WARM AIR MOVES IN AT THE ONSET FOR MOST LOCATIONS IN WESTERN
MONTANA. HOWEVER, AS THE MILDER AIR STRENGTHENS FRIDAY AFTERNOON,
SNOW LEVELS ARE EXPECTED TO RISE TO BETWEEN 4,000 TO 5,000 FEET.
THIS MAY TRANSITION VALLEY SNOW TO RAIN OR A WINTRY MIX,
PARTICULARLY FOR AREAS SOUTH OF I-90. NORTHWEST MONTANA VALLEYS
APPEAR MORE LIKELY TO HOLD ONTO THE COLD AIR LONGER, MAINTAINING
MOSTLY SNOW THROUGH FRIDAY.
CURRENT FORECASTS SHOW SNOW LEVELS PEAKING AROUND 5,000 FEET ON
SATURDAY. SATURDAY MORNING IS LOOKING PARTICULARLY CONCERNING
REGARDING THE POTENTIAL FOR VALLEY FREEZING RAIN, AS SURFACE
TEMPERATURES ARE EXPECTED TO HOVER NEAR FREEZING. TRAVELERS
PLANNING TRIPS FOR THE END OF THE WEEK AND SATURDAY ARE ADVISED TO
KEEP A CLOSE EYE ON THE FORECAST, AS SNOW ACROSS MOUNTAIN PASSES
AND A WINTRY MIX IN THE VALLEYS ARE EXPECTED TO IMPACT TRAVEL
CONDITIONS.
SNOWFALL ACCUMULATIONS THURSDAY THROUGH THE WEEKEND ARE LIKELY TO
BE MEASURED IN FEET ACROSS AREA MOUNTAINS ABOVE 5,000 FEET.
AVIATION
A BRIEF RIDGE OF HIGH PRESSURE WILL BUILD OVER THE
NORTHERN ROCKIES TODAY, BRINGING A BREAK IN THE PRECIPITATION TO
MOST LOCATIONS. HOWEVER, THIS WILL INCREASE THE LIKELIHOOD FOR
THE DEVELOPMENT OF LOW STRATUS AND/OR FREEZING FOG FOR ALL
AVIATION SITES ACROSS WESTERN MONTANA AND NORTH-CENTRAL IDAHO. IF
FOG DOES ULTIMATELY DEVELOP THIS MORNING, THE TIMING FOR REDUCED
VISIBILITY IS LIKELY TO BE BETWEEN 03/1200Z-03/1800Z. LOW CEILINGS
DUE TO STRATUS WILL HOWEVER LINGER THROUGH THE DAY TODAY.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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