579
FXUS65 KMSO 230900
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
300 AM MDT THU APR 23 2026
DISCUSSION
KEY MESSAGES:
- A POTENTIALLY IMPACTFUL BAND OF HEAVY, WET SNOW COULD DISRUPT
THE THURSDAY AND FRIDAY MORNING COMMUTES ACROSS WESTERN MONTANA
VALLEYS, MOSTLY IN THE FORM OF DOWNED TREES/ POWER OUTAGES.
- COLD OVERNIGHT LOWS ON FRIDAY AND SATURDAY MORNINGS COULD IMPACT
SENSITIVE VEGETATION.
WIDESPREAD PRECIPITATION WILL CONTINUE INTO FRIDAY AS THE MONTANA
LOW MOVES EAST AND ANOTHER DISTURBANCE MOVES OVER THE NORTHERN
ROCKIES FROM THE NORTH. COLDER AIR ASSOCIATED WITH THIS SYSTEM
WILL BRING SNOW LEVELS DOWN TO MOUNTAIN PASSES AND SOME VALLEYS.
EXPECT WET, HEAVY SNOW OVER PASSES AND HIGHER VALLEYS FOR THURSDAY
MORNING. MOTORISTS SHOULD EXPECT WINTER DRIVING CONDITIONS OVER
HOMESTAKE, MACDONALD, LOLO, MARIAS, AND LOOKOUT PASSES.
VALLEY IMPACTS ARE LESS CERTAIN THAN MOUNTAIN PASSES. RAIN SHOWERS
ARE EXPECTED TO CHANGE OVER TO OR MIX WITH WET SNOW. A WAVE IS
FORECAST TO DROP SOUTH INTO THE NORTHERN ROCKIES IN THE NEXT FEW
HOURS (THURSDAY MORNING). THIS BOUNDARY WILL ALLOW FOR A PERIOD
OF ENHANCED PRECIPITATION AND HEAVY WET SNOW COULD ACCUMULATE ON
TREE BRANCHES THIS MORNING IN NORTHWEST MT AND OVERNIGHT INTO
FRIDAY MORNING FOR WEST-CENTRAL AND SOUTHWEST MT. THE BIGGEST
CONCERN WOULD BE BREAKING BRANCHES UNDER THE WEIGHT OF SNOW,
PRODUCING ISOLATED POWER OUTAGES. HIGHER VALLEYS OF SOUTHWEST MT
AND SEELEY/ SWAN VALLEYS COULD ALSO HAVE A TRACE TO 3 INCHES OF
WET, SLUSHY ACCUMULATIONS ON SIDEWALKS AND ROADS FRIDAY MORNING.
FRIDAY AND SATURDAY MORNINGS, DEPENDING ON CLEARING CLOUDS,
TEMPERATURES ARE FORECAST TO DROP INTO THE UPPER TEENS AND LOWER
20S. PLEASE PROTECT SENSITIVE VEGETATION, THAT MAY HAVE ALREADY
BEEN PLANTED OR SPROUTED.
COOLER AND SHOWERY CONDITIONS WILL CONTINUE THROUGH LATE SUNDAY,
WITH THE POTENTIAL OF A WEAK WAVE PRODUCING MORE ORGANIZED SHOWERS
ON SUNDAY.
AVIATION
SHOWERS ARE COMING TO AN END ALONG AND WEST OF US-93,
IE KGPI, KMSO, KSMN, AND KHRF. HOWEVER, THE ATMOSPHERE IS
SATURATED IN THESE LOCATIONS AND LOWER CEILINGS ARE EXPECTED TO
PERSIST THROUGHOUT THE MORNING HOURS. THROUGH 23/1000Z, PERIODS OF
LIGHT SNOW ARE EXPECTED AT KBTM, PRODUCING 1SM OR LESS VISIBILITY
AND CEILINGS DOWN TO 1000 FEET OR LESS.
THE NORTHERN ROCKIES AIRSPACE WILL REMAIN IN NORTHWEST FLOW
THROUGHOUT THE AFTERNOON WITH RAIN AND SNOW SHOWERS AT ALL
TERMINALS POTENTIALLY PRODUCING TEMPORARY IFR CONDITIONS IN
SHOWERS. A MORE ORGANIZED BAND OF SHOWERS IS POSSIBLE ALONG I-90
OVERNIGHT INTO FRIDAY MORNING FROM KMSO TO KBTM.
MSO WATCHES/WARNINGS/ADVISORIES
MT...WINTER WEATHER ADVISORY UNTIL NOON MDT FRIDAY FOR
BITTERROOT/SAPPHIRE MOUNTAINS...BUTTE/BLACKFOOT REGION...
POTOMAC/SEELEY LAKE REGION.
WINTER WEATHER ADVISORY UNTIL 6 PM MDT THURSDAY FOR WEST GLACIER
REGION.
ID...WINTER WEATHER ADVISORY UNTIL NOON MDT /11 AM PDT/ FRIDAY FOR
EASTERN LEMHI COUNTY...SOUTHERN CLEARWATER MOUNTAINS...
WESTERN LEMHI COUNTY.
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