867
FXUS65 KMSO 210714
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
114 AM MDT TUE APR 21 2026
DISCUSSION
KEY MESSAGES:
- WELL ABOVE NORMAL TEMPERATURES TODAY, WITH VALLEY REACHING THE
UPPER 70S TO 80S.
- RAIN SHOWERS AND A FEW THUNDERSTORMS ARE POSSIBLE THIS EVENING,
BRINGING A RISK OF GUSTY WINDS, ESPECIALLY IN NORTH-CENTRAL
IDAHO AND NW MONTANA.
- WIDESPREAD RAIN AND MUCH COLDER TEMPERATURES ARRIVE WEDNESDAY
THROUGH FRIDAY.
A STRONG LOW PRESSURE SYSTEM IS LOCATED OFF THE WEST COAST. THIS
SYSTEM WILL CONTINUE PROGRESSING EASTWARD, BRINGING A SIGNIFICANT
CHANGE IN THE WEATHER TO THE NORTHERN ROCKIES BY TOMORROW. IN THE
MEANTIME, SUMMER-LIKE CONDITIONS ARE EXPECTED TODAY WITH DAYTIME
HIGH TEMPERATURES 20 TO 30 DEGREES ABOVE NORMAL. RECORD HIGH
TEMPERATURES WILL BE POSSIBLE IN MISSOULA, BUTTE, AND KALISPELL AS
TEMPERATURES CLIMB INTO THE UPPER 70S AND LOW 80S. DRY CONDITIONS
AND STRONG SOUTHWEST WINDS ACROSS SOUTHWEST MONTANA WILL ALSO
BRING CONCERNS FOR ELEVATED FIRE DANGER.
THE CHANGE ARRIVES TONIGHT AND EARLY TOMORROW MORNING. THE PACIFIC
STORM SYSTEM WILL MAKE ITS WAY INTO THE NORTHERN ROCKIES, BRINGING
A STRONG COLD FRONT WITH IT. EXPECT DAYTIME HIGHS TOMORROW TO BE
ABOUT 20 TO 25 DEGREES COOLER THAN TODAY. THE FRONT WILL ALSO
BRING STRONG WESTERLY WINDS AND ABUNDANT MOISTURE, RESULTING IN
WIDESPREAD MODERATE TO HEAVY RAIN AND ISOLATED THUNDERSTORMS.
48-HOUR PRECIPITATION TOTALS ENDING FRIDAY MORNING WILL FAVOR THE
MOUNTAINS OF NORTH-CENTRAL IDAHO, THE BITTERROOT CREST, AND
NORTHWEST MONTANA, WHERE THERE IS A 70 PERCENT PROBABILITY OF
EXCEEDING ONE INCH AND A 20 TO 40 PERCENT OF EXCEEDING TWO INCHES.
WHILE LOCAL RIVERS AND STREAMS WILL RISE, WIDESPREAD FLOODING IS
UNLIKELY AT THIS TIME. PLEASE STAY ALERT FOR WATER POOLING ON
ROADWAYS AND THE POTENTIAL FOR SMALL ROCKSLIDES OR DEBRIS FLOWS IN
STEEP TERRAIN.
SNOW LEVELS WILL DROP LATER THURSDAY, LOWERING ENOUGH FOR 3 TO 6
INCHES OF SNOW TO FALL ON LOOKOUT, LOLO, AND LOST TRAIL PASSES IN
THE BITTERROOT MOUNTAINS AND MARIAS, MCDONALD, AND HOMESTAKE
PASSES ALONG THE CONTINENTAL DIVIDE BY FRIDAY MORNING. THERE IS A
15 PERCENT PROBABILITY THAT UP TO 10 INCHES OF SNOW COULD FALL
ALONG LOST TRAIL AND HOMESTAKE PASSES. IF YOU ARE TRAVELING OVER
AREA PASSES THURSDAY EVENING AND FRIDAY MORNING, BE PREPARED FOR
WINTER DRIVING CONDITIONS.
AS FOR THE VALLEYS, IF THERE IS A PERIOD FOR VALLEY SNOW, IT WILL
BE EARLY FRIDAY MORNING. THERE IS CURRENTLY A 15 TO 20 PERCENT
PROBABILITY OF AN INCH OF SNOW, AND A 50 PERCENT FOR THE HIGHER
VALLEYS ALONG THE CONTINENTAL DIVIDE FOR THE FRIDAY MORNING
COMMUTE.
AVIATION
MOSTLY CLEAR SKIES AND LOCAL MOUNTAIN BREEZES WILL
RESULT IN GOOD FLYING CONDITIONS (VFR) THOUGH THIS MORNING. THERE
IS A 10 TO 15 PERCENT PROBABILITY FOR ISOLATED THUNDERSTORMS
DEVELOPING LATER THIS EVENING BETWEEN 22/000Z AND 22/0600Z FOR ALL
OF NORTHWEST MONTANA AND NORTH-CENTRAL IDAHO.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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