707
FXUS65 KMSO 161942
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
142 PM MDT MON MAR 16 2026
DISCUSSION
KEY MESSAGES:
- SNOW WILL TURN TO RAIN THIS AFTERNOON AND EVENING AS
TEMPERATURES RISE.
- HIGH PRESSURE WILL RESULT IN TEMPERATURES BECOMING WELL ABOVE
NORMAL AS SOON AS TUESDAY AND PEAKING ON THURSDAY AND FRIDAY
WHEN DAYTIME HIGHS REACH 15-20 DEGREES ABOVE NORMAL.
- THE RAPID RISE IN TEMPERATURES WILL QUICKLY MELT THE FRESH
VALLEY SNOW, WHICH MAY LEAD TO URBAN RUNOFF AND PONDING OF
WATER IN LOW-LYING AREAS AND POORLY DRAINED STREETS.
AS SNOW TRANSITIONS TO RAIN THIS AFTERNOON AND EVENING WITH
WARMING TEMPERATURES, WE SAY GOODBYE TO WINTER FOR NOW, AND LOOK
TOWARDS A PERIOD OF SPRINGLIKE WEATHER THIS WEEK. SATELLITE
IMAGERY THIS AFTERNOON DEPICTS A CIRCULATION OF HIGH PRESSURE OFF
THE COAST OF SOUTHERN CALIFORNIA. MOISTURE TODAY WAS RIDING UP AND
OVER THE RIDGE, LANDING IN THE NORTHERN ROCKIES. THAT HIGH WILL
SHIFT EAST OVER THE COMING DAYS, FORMING A BROAD, LOW-AMPLITUDE
RIDGE OF HIGH PRESSURE OVER THE NORTHERN ROCKIES. A WESTERLY
UPPER-LEVEL JET STAYS POINTED AT, OR JUST NORTH OF, THE NORTHERN
ROCKIES ON THE NORTH EDGE OF THE RIDGE. THE POSITION OF THE JET
WILL BRING PACIFIC MOISTURE AND ELEVATED WESTERLY OR SOUTHWESTERLY
WINDS. THAT PACIFIC MOISTURE WILL KEEP PRECIPITATION IN THE
FORECAST FOR NORTHWEST AND WEST-CENTRAL MONTANA, AS WELL AS
CLEARWATER AND NORTHERN IDAHO COUNTIES, ON TUESDAY NIGHT THROUGH
FRIDAY. HOWEVER, WARMING TEMPERATURES WILL KEEP SNOW OUT OF THE
QUESTION IN THE VALLEYS AS SNOW LEVELS GET UP TO ABOUT 7,000 FT ON
TUESDAY, AND CONTINUE TO RISE ON THURSDAY AND FRIDAY.
THURSDAY AND FRIDAY WILL BE THE WARMEST DAYS OF THE WEEK.
TEMPERATURES IN THE VALLEYS OF WESTERN MONTANA WILL FLIRT WITH 70,
WHILE THE LOWER SALMON AND CLEARWATER VALLEYS IN IDAHO WILL PUSH
80 DEGREES. THE DAYTIME HIGH RECORD AT BUTTE WILL BE IN THE
CROSSHAIRS ON BOTH THURSDAY AND FRIDAY, WHERE THE RECORD IS 65 ON
BOTH DAYS.
URBAN FLOODING WILL BECOME A CONCERN WITH RAIN AND RAPIDLY
MELTING LOW-ELEVATION SNOW. EXPECT LOCALIZED PONDING OF WATER IN
LOW-LYING AREAS, POOR DRAINAGE ZONES, AND URBAN ROADWAYS FROM
TUESDAY INTO THE WEEKEND.
MODEL ENSEMBLES DIVERGE FOR THE WEEKEND, SOME MEMBERS SHOWING THE
RIDGE FLATTENING FURTHER (BETTER CHANCES FOR MORE PRECIPITATION),
OTHERS KEEPING MORE OF A RIDGE (ALBEIT A LOW-AMPLITUDE RIDGE).
THE SPLIT IS ABOUT 50-50, SO CONFIDENCE IS VERY LOW ON EITHER
OUTCOME.
AVIATION
AS THE WARM FRONT PROGRESSES TODAY, SNOW LEVELS WILL
RISE, WITH PRECIPITATION TRANSITIONING PREDOMINANTLY TO RAIN BY
LATE THIS AFTERNOON. HOWEVER, NORTHWEST MONTANA, INCLUDING KGPI,
HAS BEEN STUBBORNLY SLOW TO WARM, WITH SNOW CONTINUING TO BE
REPORTED THIS AFTERNOON. VISIBILITIES AND CEILINGS WILL GRADUALLY
IMPROVE TO MVFR/VFR AS THE TRANSITION TO RAIN OCCURS, THOUGH
WIDESPREAD MOUNTAIN AND TERRAIN OBSCURATIONS WILL PERSIST THROUGH
TONIGHT.
LOOKING AHEAD, THE REGION WILL REMAIN ON THE PERIPHERY OF A
BUILDING RIDGE FOR THE REST OF THE WEEK. MOISTURE STREAMING OVER
THE RIDGE WILL PRODUCE INTERMITTENT SHOWERS, BUT UNSEASONABLY WARM
TEMPERATURES MEAN PRECIPITATION WILL FALL AS RAIN EVEN AT HIGHER
ELEVATIONS.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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