043
FXUS65 KMSO 251935
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
135 PM MDT SAT APR 25 2026
DISCUSSION
KEY MESSAGES:
- NEAR RECORD COLD TEMPERATURES FORECAST FOR SUNDAY MORNING
- SLOW WARMING TREND WITH LINGERING SHOWERS, ESPECIALLY DURING
THE AFTERNOON AND EVENING
THE COLD AIR THAT HAS SETTLED OVER THE NORTHERN ROCKIES WILL
ALLOW TEMPERATURES TO DROP NEAR TO WELL BELOW FREEZING IN MANY
LOCATIONS ACROSS THE REGION TONIGHT PUTTING FLOWERING PLANTS AND
ABOVE GROUND PLUMBING IN DANGER OF DAMAGE, SO A FROST ADVISORY AND
FREEZE WARNINGS REMAIN IN PLACE.
THE NORTHERN ROCKIES WILL REMAIN UNDER NORTHERLY TO NORTHWESTERLY
FLOW THIS WEEKEND INTO MID NEXT WEEK. THIS FLOW PATTERN WILL ALLOW
FOR A VERY GRADUAL WARMING TREND WITH TEMPERATURES FINALLY
REACHING NEAR NORMAL SEASONAL READINGS BY WEDNESDAY. THE FLOW
PATTERN IS ALSO CONDUCIVE TO LINGERING LIGHT SHOWERS, ESPECIALLY
ACROSS WESTERN MONTANA. THE SHOWER ACTIVITY WILL PICK UP IN
COVERAGE AND INTENSITY DURING THE AFTERNOON HOURS AND THEN
DIMINISH AFTER SUNSET EACH DAY. A FEW SUBTLE FEATURES ARE EXPECTED
TO PASS THROUGH THE REGION UNDER THIS FLOW PATTERN WHICH APPEARS
TO KEEP THE SHOWER ACTIVITY TO LINGER SLIGHTLY LONGER, ESPECIALLY
ALONG THE CONTINENTAL DIVIDE AROUND GLACIER NATIONAL PARK. THESE
SHOWERS COULD CREATE ISOLATED SNOW COVERED ROADS DURING THE
OVERNIGHT HOURS AND INTO THE EARLY MORNING HOURS.
THE LONG TERM GUIDANCE IS SHOWING A WEAK RIDGE OF HIGH PRESSURE
MOVING OVER THE REGION BY THE LATTER PART OF THE WORK WEEK. THIS
RIDGE APPEARS TO CAUSE TEMPERATURES TO CLIMB TO AROUND 10 DEGREES
ABOVE NORMAL ALONG WITH DRIER CONDITIONS. THIS RIDGE APPEARS TO BE
SHORT LIVED AS ANOTHER DISTURBANCE IS EXPECTED TO IMPACT THE
WESTERN UNITED STATES BY THE WEEKEND.
AVIATION
SHALLOW MOISTURE AND INSTABILITY HAS ALLOWED FOR
SCATTERED SHOWERS ACROSS THE NORTHERN ROCKIES THIS AFTERNOON,
WITH ACTIVITY FOCUSED ALONG AND NORTH OF THE I-90 CORRIDOR. SHOWER
ACTIVITY HAS LARGELY DEVELOPED ACROSS THE HIGHER TERRAIN, WHERE
BRIEF PERIODS OF IFR/MVFR VISIBILITY CAN BE EXPECTED FROM
RAIN/SNOW SHOWERS. THESE SHOWERS WILL BE CONVECTIVE IN NATURE,
WITH TURBULENCE NEAR CONVECTIVE CORES. HIGH-RESOLUTION MODELS
SUGGEST SHOWER ACTIVITY WILL DEVELOP NEAR KBTM THIS EVENING, WITH
A 30% CHANCE FOR BRIEF VISIBILITY REDUCTIONS TO 3SM AFTER
26/0200Z. OVERNIGHT, A TIGHTENING PRESSURE GRADIENT WILL DRIVE
EAST-NORTHEASTERLY WINDS THROUGH TERRAIN-CHANNELED VALLEYS,
INTRODUCING AREAS OF TURBULENCE AND LOCALIZED CROSSWINDS AT
IMPACTED TERMINALS. FURTHERMORE, STRATUS CLOUDS WILL EXPAND, WITH
3,000-5,000 FEET CEILINGS ACROSS WESTERN MT, WITH THE LOWEST
CEILINGS ALONG THE DIVIDE.
MSO WATCHES/WARNINGS/ADVISORIES
MT...FREEZE WARNING UNTIL 8 AM MDT SUNDAY FOR BITTERROOT/SAPPHIRE
MOUNTAINS...FLATHEAD/MISSION VALLEYS...KOOTENAI/CABINET
REGION...LOWER CLARK FORK REGION...MISSOULA/BITTERROOT
VALLEYS.
ID...FREEZE WARNING UNTIL 8 AM MDT /7 AM PDT/ SUNDAY FOR EASTERN
LEMHI COUNTY...NORTHERN CLEARWATER MOUNTAINS...SOUTHERN
CLEARWATER MOUNTAINS.
FROST ADVISORY UNTIL 8 AM MDT /7 AM PDT/ SUNDAY FOR
OROFINO/GRANGEVILLE REGION...WESTERN LEMHI COUNTY.
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