659
FXUS65 KMSO 241905
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
105 PM MDT TUE MAR 24 2026
DISCUSSION
KEY MESSAGES:
- ATMOSPHERIC RIVER: WIDESPREAD PRECIPITATION, HIGH ELEVATION
SNOW, AND GUSTY WINDS THROUGH WEDNESDAY.
- MOUNTAIN SNOW: SNOW ACCUMULATIONS WILL PRIMARILY IMPACT HIGH
ELEVATIONS ABOVE 6,000 FEET, FOLLOWED BY MINOR TRAVEL IMPACTS
ON MOUNTAIN PASSES, MAINLY WEDNESDAY NIGHT.
- WIND AND FIRE RISK: STRONG WINDS ARRIVE WEDNESDAY. COMBINED
WITH LOW HUMIDITY, CONFIDENCE IS GROWING FOR CRITICAL FIRE
WEATHER CONDITIONS EAST OF THE DIVIDE IN SOUTHWEST MONTANA.
- MILD WEEKEND: A WARMING TREND BEGINS FRIDAY, BRINGING ABOVE-
NORMAL TEMPERATURES BY SATURDAY.
ATMOSPHERIC RIVER (TODAY-TONIGHT): A BRIEF ATMOSPHERIC RIVER
ARRIVES THIS AFTERNOON, BRINGING 0.5" TO 1.5" OF LIQUID
PRECIPITATION TO THE IDAHO/MONTANA BORDER AND NORTHWEST MONTANA.
SNOW LEVELS WILL RISE SHARPLY TO NEAR 7,000 FEET TONIGHT. WHILE
MAINSTEM RIVERS SHOULD REMAIN BELOW ACTION STAGE, CREEKS IN
LINCOLN, SANDERS, AND MINERAL COUNTIES WILL SEE FURTHER RISES BUT
OVERALL THE CONCERN FOR FLOODING IS MINOR. ROCK AND MUDSLIDES
REMAIN A POSSIBILITY ALONG TERRAIN-ADJACENT ROADWAYS.
COLD FRONT & SNOW LEVELS (WEDNESDAY-THURSDAY): A POTENT COLD
FRONT CROSSES THE REGION WEDNESDAY MORNING.
- NORTHWEST MONTANA: SNOW LEVELS WILL CRASH TO 3,500 FEET BY
WEDNESDAY AFTERNOON. WHILE LOOKOUT AND MARIAS PASSES MAY SEE
SEVERAL INCHES OF ACCUMULATION WEDNESDAY NIGHT INTO THURSDAY
MORNING, TRAVEL IMPACTS APPEAR MINOR.
- SOUTHWEST MONTANA/LEMHI COUNTY: LEVELS WILL RISE TO 7,000 FEET
AHEAD OF THE FRONT BEFORE FALLING REGION-WIDE WEDNESDAY NIGHT.
WIND HAZARDS (TONIGHT-WEDNESDAY): A 40-60 KT LOW-LEVEL JET WILL
PRODUCE WIDESPREAD WIND CONCERNS.
- PEAK GUSTS: 50-70% CHANCE OF GUSTS > 40 MPH IN LEMHI COUNTY AND
SOUTHWEST MONTANA; 25-50% CHANCE OF 30-40 MPH GUSTS FOR MOST
WESTERN MONTANA VALLEYS (THOUGH HIGHER PROBABILITIES IN NW
MONTANA).
- HIGH TERRAIN: GUSTS UP TO 60 MPH ALONG THE CONTINENTAL DIVIDE.
- IMPACTS: EXPECT CHOPPY LAKE CONDITIONS, THE POTENTIAL FOR
LOCALIZED TREE DAMAGE AND POWER OUTAGES.
CRITICAL FIRE WEATHER (WEDNESDAY): A RED FLAG WARNING IS IN
EFFECT FOR THE EAST BEAVERHEAD (SOUTHWEST MONTANA) WEDNESDAY
AFTERNOON. THE COMBINATION OF PEAK WINDS AND RELATIVE HUMIDITY
DROPPING INTO THE TEENS WILL CREATE CRITICAL FIRE CONDITIONS AHEAD
OF THE FRONTAL PASSAGE.
EXTENDED OUTLOOK: TEMPERATURES DROP BELOW SEASONAL NORMALS
THURSDAY FOLLOWING THE FRONT. A DRYING AND WARMING TREND BEGINS
FRIDAY AS A RIDGE BUILDS, WITH TEMPERATURES RETURNING TO ABOVE-
NORMAL LEVELS BY SATURDAY. SHOWERS RETURN AS EARLY AS SUNDAY
AFTERNOON. ENSEMBLE CLUSTERS ARE IN GOOD AGREEMENT (80-90%) ON
UPPER LEVEL TROUGHING (WIDESPREAD COOLER/UNSETTLED WEATHER)
RETURNING TO THE NORTHERN ROCKIES BY THE SECOND HALF OF NEXT WEEK.
AVIATION
A FAST-MOVING ATMOSPHERIC RIVER ARRIVES THIS AFTERNOON, BRINGING
WIDESPREAD RAIN AND TERRAIN-OBSCURING CLOUDS TO NORTH- CENTRAL
IDAHO AND NORTHWEST MONTANA. CEILINGS AND VISIBILITY REDUCTIONS
WILL BECOME MORE COMMON BY MID AFTERNOON.
CEILINGS/VISIBILITY: VFR CONDITIONS WILL DETERIORATE TO AREAS OF
MVFR THIS AFTERNOON (APPROX. 21Z-00Z) ACROSS NORTH-CENTRAL IDAHO
AND NORTHWEST MONTANA AS WIDESPREAD PRECIPITATION BEGINS. EXPECT
PERSISTENT MOUNTAIN OBSCURATION ALONG THE MONTANA/IDAHO BORDER AND
THE CONTINENTAL DIVIDE THROUGH THE PERIOD.
WIND/TURBULENCE: LOW-LEVEL WIND SHEAR AND MECHANICAL TURBULENCE
WILL BECOME A HAZARD THIS EVENING THROUGH WEDNESDAY. SURFACE
GUSTS OF 25-40 KT ARE EXPECTED IN WESTERN MONTANA VALLEYS BY LATE
WEDNESDAY MORNING AS A COLD FRONT PASSES. BY WEDNESDAY AFTERNOON,
GUSTS WILL EXCEED 40 KT OVER RIDGES AND THROUGH WIND- PRONE
CANYONS IN SOUTHWEST MONTANA AND LEMHI COUNTY (NEAR KBTM AND
KSMN).
MSO WATCHES/WARNINGS/ADVISORIES
MT...WIND ADVISORY FROM 11 AM TO 7 PM MDT WEDNESDAY FOR
BUTTE/BLACKFOOT REGION.
WIND ADVISORY FROM 6 AM TO 7 PM MDT WEDNESDAY FOR
KOOTENAI/CABINET REGION.
WIND ADVISORY FROM 8 AM TO 7 PM MDT WEDNESDAY FOR
FLATHEAD/MISSION VALLEYS...WEST GLACIER REGION.
RED FLAG WARNING FROM NOON TO 9 PM MDT WEDNESDAY FOR EAST
BEAVERHEAD.
ID...WIND ADVISORY FROM 11 AM TO 7 PM MDT WEDNESDAY FOR EASTERN LEMHI
COUNTY...WESTERN LEMHI COUNTY.
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