453
FXUS65 KMSO 190809
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
209 AM MDT SAT APR 19 2025
DISCUSSION
KEY MESSAGES:
- GUSTY WINDS ASSOCIATED WITH A COLD FRONT, MOUNTAIN SNOW, AND
VALLEY RAIN SHOWERS LATE THIS AFTERNOON
- SCATTERED SHOWERS, BREEZY WINDS, AND POTENTIAL FOR MINOR ROAD
IMPACTS OVER MOUNTAIN PASSES.
- UNSETTLED WEATHER LASTS THROUGH MOST OF NEXT WEEK, BREEZY
AFTERNOONS, SLIGHT AND GRADUAL WARMING TREND.
A RELATIVELY WEAK PACIFIC COLD FRONT ASSOCIATED WITH A SHORTWAVE
TROUGH WILL SLIDE SOUTHEAST OUT OF THE PACIFIC NW LATE THIS
AFTERNOON AND INTO THE EVENING. THIS SYSTEM WILL NOT BE AS COLD
AS THE PREVIOUS EVENT LEADING TO SCATTERED MOUNTAIN SNOW AND
VALLEY RAIN SHOWERS. AN INCREASE IN SUSTAINED WESTERLY WINDS AND
GUSTS AROUND 25 MPH SHOULD BE QUITE COMMON ACROSS MUCH OF THE AREA
WITH THIS FRONTAL PASSAGE.
A SUCCEEDING COOLER TROUGH WILL DIG SOUTHEAST OUT OF BRITISH
COLUMBIA INTO EARLY NEXT WEEK CAPABLE OF PRODUCING PERIODS OF
VALLEY RAIN AND SNOW SHOWERS ABOVE 4,000FT LATE SUNDAY INTO THE
FIRST HALF OF MONDAY. A LOW-PROBABILITY CHANCE EXISTS FOR
SNOWFLAKES FALLING TO SOME VALLEY FLOORS MONDAY MORNING WITH NO
EXPECTED ACCUMULATION AT THIS TIME. THIS COOLER TROUGH WILL ALSO
BRING ANOTHER BREEZY SET OF DAYS, WITH A 50 TO 70 PERCENT
PROBABILITY FOR GUSTS REACHING 30 MPH DURING THE AFTERNOON HOURS
ON SUNDAY AND MONDAY. AS A RESULT, LOCAL LAKES WITH OPEN WATER
INCLUDING FLATHEAD LAKE MAY EXPERIENCE ROUGH AND CHOPPY CONDITIONS
DURING THIS TIME FRAME.
ENSEMBLE MEMBERS ARE ALIGNING INTO AGREEMENT FOR A RELATIVELY
STATIONARY, AND BROAD, LONGWAVE TROUGH BEING REINFORCED OVER THE
WEST COAST OF THE U.S FOR MUCH OF NEXT WEEK. THIS WILL CONTINUE TO
BRING AN UNSETTLED, YET VERY SEASONABLE, WEATHER PATTERN UNDER
LIGHT WEST-SOUTHWESTERLY FLOW THROUGH AT LEAST THE 24TH OF APRIL.
AVIATION
VFR CONDITIONS WILL PREVAIL THROUGH THIS AFTERNOON.
WINDS REMAIN LIGHT UNTIL AROUND 19/1900Z FOR GPI AND 19/2100Z FOR
KMSO, KHRF, KBTM AND KSMN. THEN, GUSTS OF 15-25 KTS OCCUR
ASSOCIATED WITH A WEAK PACIFIC COLD FRONT. SCATTERED LIGHT SHOWERS
WILL ACCOMPANY THE FRONT THAT MAY BRIEFLY LOWER CEILINGS AND THE
VISIBILITY. MOUNTAIN OBSCURATIONS WILL BE COMMON THROUGHOUT THE
NORTHERN ROCKIES DURING THIS TIME AS WELL.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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