112
FXUS65 KMSO 151918
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
1218 PM MST SUN FEB 15 2026
DISCUSSION
KEY MESSAGES:
- STRONG COLD FRONT TUESDAY, BRINGING COLDER TEMPERATURES,
WIDESPREAD SNOW, AND RISK FOR SNOW SQUALLS.
- ARCTIC INTRUSION NORTH OF I-90 AND ALONG THE DIVIDE TUESDAY
NIGHT INTO WEDNESDAY MORNING.
- SNOW SHOWERS ALONG WITH COLDER TEMPERATURES WEDNESDAY INTO
FRIDAY.
TODAY THROUGH MONDAY AFTERNOON:
*SATELLITE AND REGIONAL RADAR IMAGERY THIS AFTERNOON SHOW PACIFIC
MOISTURE STREAMING INTO THE NORTHERN ROCKIES VIA WEST-SOUTHWEST
FLOW. WHILE TODAY HAS BEEN RELATIVELY MILD UNDER A SOUTHERLY
GRADIENT PUSHING SNOW LEVELS TOWARD 4,500-5,000 FEET SOUTH OF
I-90, A TRANSITION IS ALREADY UNDERWAY. THIS EVENING AND TONIGHT,
SHOWER ACTIVITY WILL SHIFT NORTHWARD, FOCUSING A RENEWED PERIOD
OF LIGHT SNOW ACCUMULATIONS ACROSS NORTHWEST MONTANA. LOOKOUT AND
MARIAS PASSES SHOULD EXPECT PERIODIC IMPACTS FROM LIGHT TO
MODERATE SNOW, WHILE LOCALIZED VALLEY ACCUMULATIONS OF UP TO ONE
INCH BE CENTERED ON LINCOLN, FLATHEAD, AND EASTERN MISSOULA
COUNTIES (SPECIFICALLY THE POTOMAC AND SEELEY LAKE REGIONS). MILD
TEMPERATURES WILL RETURN MONDAY AFTERNOON, AS VALLEY HIGHS CLIMB
INTO THE 40S AND 50S AS SOUTHERLY FLOW DEEPENS AHEAD OF A COLD
FRONT.
TUESDAY COLD FRONT:
*THE PRIMARY FOCUS OF THIS FORECAST REMAINS THE ARRIVAL OF AN
UPPER LEVEL TROUGH AND DEEPENING SURFACE LOW TRACKING FROM THE
GREAT BASIN INTO SOUTHWEST MONTANA ON TUESDAY. THIS EVOLUTION
DRIVES A POTENT COLD FRONT ACROSS THE REGION, CHARACTERIZED BY
RAPIDLY FALLING SNOW LEVELS AND A FOCUSED BAND OF FRONTAL
PRECIPITATION.
*OF PARTICULAR CONCERN IS THE POTENTIAL FOR SNOW SQUALLS ACROSS
SOUTHWEST MONTANA AND LEMHI COUNTY TUESDAY MORNING. HIGH-
RESOLUTION GUIDANCE SUGGESTS SHARP PRESSURE RISES AND WIND GUSTS
EXCEEDING 35 MPH COINCIDING WITH INTENSE SNOW BURSTS ALONG THE
FRONT. THIS COMBINATION CREATES A HIGH RISK FOR FLASH FREEZE
CONDITIONS, ESPECIALLY ON THE I-90 AND I-15 CORRIDORS NEAR BUTTE,
WHERE TEMPERATURES WILL DROP RAPIDLY JUST AS THE HEAVIEST
PRECIPITATION ARRIVES.
*SNOWFALL TOTALS WITH THIS SYSTEM WILL BE MOST SIGNIFICANT IN THE
MOUNTAINS, WITH A 48-HOUR RANGE (25TH-75TH PERCENTILE) OF 4 TO 10
INCHES ABOVE 4,000 FEET. HOWEVER, VALLEY SNOW WILL BE WIDESPREAD;
NBM PROBABILITIES FOR MEASURABLE ACCUMULATION EXCEED 50% FOR ALL
VALLEY AREAS IN THE NORTHERN ROCKIES. WE ARE CLOSELY MONITORING
THE FLATHEAD VALLEY, EASTERN PORTIONS OF FLATHEAD LAKE, AND THE
SEELEY/POTOMAC CORRIDOR FOR HIGHER TOTALS. A MESOSCALE SNOW BAND
IS EXPECTED TO DEVELOP ON THE NORTHWEST PERIPHERY OF THE SURFACE
LOW, WHICH, COMBINED WITH FAVORABLE UPSLOPE FLOW, COULD LEAD TO
LOCALIZED HIGHER SNOW RATES TUESDAY MORNING INTO THE EARLY
AFTERNOON.
ARCTIC INTRUSION TUESDAY NIGHT AND WEDNESDAY MORNING:
*BY TUESDAY NIGHT, THE FOCUS SHIFTS TO A HIGH-PROBABILITY (80-90%)
ARCTIC INTRUSION SPILLING OVER THE CONTINENTAL DIVIDE. WHILE THE
WESTWARD EXTENT OF THIS COLD AIR REMAINS UNCERTAIN NEAR THE I-90
CORRIDOR (CURRENTLY A 30% PROBABILITY OF A DEEP PUSH), THE
TEMPERATURE DROP WILL BE SIGNIFICANT ALONG THE DIVIDE. EXPECT
SINGLE DIGITS AND TEENS BY WEDNESDAY MORNING, WITH WIND CHILLS
FALLING BELOW ZERO ALONG US HIGHWAY 2 AND MACDONALD PASS.
EXTENDED OUTLOOK (WEDNESDAY THROUGH FRIDAY):
*A BROAD LONGWAVE TROUGH WILL KEEP THE REGION IN AN UNSETTLED
WEST-NORTHWEST FLOW THROUGH THE REMAINDER OF THE WEEK. THIS
PATTERN FAVORS DAILY SNOW SHOWERS WITH SNOW LEVELS REMAINING AT
VALLEY FLOORS. WHILE THE MOST CONSISTENT ACCUMULATIONS WILL
TARGET THE MONTANA/IDAHO BORDER, TRAVELERS SHOULD BE PREPARED FOR
VARIABLE CONDITIONS AND QUICK VISIBILITY REDUCTIONS AREA-WIDE.
WEDNESDAY STANDS OUT FOR NORTH-CENTRAL IDAHO, WHERE A MID-LEVEL
CIRCULATION WILL LIKELY FOCUS SNOW SHOWERS ACROSS IDAHO AND
CLEARWATER COUNTIES, BRINGING A 50% OR GREATER CHANCE FOR AN INCH
OF ACCUMULATION.
AVIATION
WIDESPREAD TERRAIN OBSCURATIONS AND VARYING FLIGHT
CATEGORIES CONTINUE ACROSS THE NORTHERN ROCKIES AS PERSISTENT
SOUTHWESTERLY FLOW DRIVES OROGRAPHIC PRECIPITATION AGAINST THE
IDAHO-MONTANA BORDER, OCCASIONALLY REACHING VALLEYS. A STATIONARY
THERMAL BOUNDARY ALONG THE I-90 CORRIDOR WILL LIFT NORTHWARD
TONIGHT, SHIFTING THE FOCUS OF THE SHOWERS INTO NORTHWEST MONTANA.
SOUTHWESTERLY WINDS PICK UP ON MONDAY AFTERNOON WITH GUSTS OF
20-30 KTS FOR TERMINAL SITES.
A STRONGER AND VERY DYNAMIC SURFACE LOW AND COLD FRONT WILL BRING
WIDESPREAD SNOW AND GUSTY WESTERLY WINDS TO THE REGION MONDAY
NIGHT AND TUESDAY MORNING. SNOW SQUALLS ARE ALSO A CONCERN ON
TUESDAY MORNING ACROSS SOUTHWEST MONTANA INTO LEMHI COUNTY.
MSO WATCHES/WARNINGS/ADVISORIES
MT...WINTER WEATHER ADVISORY FROM 11 PM MONDAY TO 5 PM MST TUESDAY
FOR BITTERROOT/SAPPHIRE MOUNTAINS.
WINTER WEATHER ADVISORY FROM 2 AM TO 5 PM MST TUESDAY FOR
BUTTE/BLACKFOOT REGION...FLATHEAD/MISSION VALLEYS...
KOOTENAI/CABINET REGION...POTOMAC/SEELEY LAKE REGION...WEST
GLACIER REGION.
WINTER WEATHER ADVISORY FROM 5 PM MONDAY TO 5 PM MST TUESDAY FOR
LOWER CLARK FORK REGION.
ID...WINTER WEATHER ADVISORY FROM 10 PM MONDAY TO 4 PM PST TUESDAY
FOR NORTHERN CLEARWATER MOUNTAINS...SOUTHERN CLEARWATER
MOUNTAINS.
WINTER WEATHER ADVISORY FROM 7 PM MONDAY TO 10 AM PST TUESDAY
FOR LOWER HELLS CANYON/SALMON RIVER REGION...
OROFINO/GRANGEVILLE REGION.
WINTER WEATHER ADVISORY FROM 2 AM TO 5 PM MST TUESDAY FOR
EASTERN LEMHI COUNTY...WESTERN LEMHI COUNTY.
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