086
FXUS65 KMSO 071851
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
1251 PM MDT WED OCT 7 2026
DISCUSSION
KEY MESSAGES:
- WARM CONDITIONS CONTINUE THROUGH FRIDAY.
- GUSTY WEST WINDS FRIDAY AFTERNOON CREATING NEAR-CRITICAL FIRE
WEATHER CONDITIONS ACROSS SOUTHWEST MONTANA.
- SHARP COLD FRONT SATURDAY BRINGS A DRAMATIC WINTER TRANSITION.
- GUSTY EAST-NORTHEAST WINDS SATURDAY NIGHT.
- HARD FREEZE MONDAY AND TUESDAY MORNINGS.
HIGH PRESSURE CONTINUES TO KEEP CONDITIONS WARM AND DRY ACROSS THE
NORTHERN ROCKIES THROUGH LATE WEEK, WITH TEMPERATURES REMAINING 15
DEGREES ABOVE NORMAL THROUGH FRIDAY. ON FRIDAY AFTERNOON, GUSTY
WEST-TO-SOUTHWESTERLY WINDS WILL INCREASE AHEAD OF AN INCOMING
TROUGH, GENERATING NEAR-CRITICAL FIRE WEATHER CONCERNS ACROSS
SOUTHWEST MONTANA.
CONFIDENCE REMAINS VERY HIGH FOR A COMPLETE PATTERN REVERSAL
STARTING SATURDAY AS A STRONG COLD FRONT PLUNGES SOUTHWARD ACROSS
THE REGION. AS HIGH PRESSURE BUILDS EAST OF THE DIVIDE, AN EAST-
TO-NORTHEAST PRESSURE GRADIENT WILL TIGHTEN RAPIDLY SATURDAY NIGHT
INTO SUNDAY MORNING. THIS WILL PRODUCE GUSTY EAST TO NORTHEAST
WINDS ACROSS PASS LEVELS AND EAST-WEST VALLEYS. FURTHERMORE, MODEL
SOUNDINGS INDICATE FAVORABLE CROSS-BARRIER FLOW AND STABILITY
PROFILES FOR A POTENTIAL BORA (DOWNSLOPING WIND) EVENT ALONG THE
WESTERN SLOPES OF THE MISSION MOUNTAINS SATURDAY NIGHT.
PRECIPITATION AND SNOWFALL IMPACTS:
LATEST MODEL GUIDANCE CONTINUES TO LOCK IN ON THE CONTINENTAL
DIVIDE AND SOUTHWEST MONTANA FOR THE BULK OF THE MOISTURE. FOR
THE 36-HOUR WINDOW ENDING SUNDAY EVENING:
CONTINENTAL DIVIDE TERRAIN: 5 TO 12 INCHES OF SNOW EXPECTED IN
THE MOUNTAINS ALONG THE DIVIDE.
MOUNTAIN PASSES: MARIAS, MACDONALD AND HOMESTAKE PASSES ARE
CURRENTLY PROJECTED TO RECEIVE 2 TO 6 INCHES, WHICH WILL CREATE
HAZARDOUS TRAVEL CONDITIONS.
VALLEYS: VALLEYS SITUATED EAST OF HIGHWAY 93 CAN EXPECT 1 TO 3
INCHES OF SLUSHY ACCUMULATION, WHILE WESTERN VALLEYS CLOSER TO
IDAHO SEE LOWER PROBABILITIES.
TEMPERATURES AND HARD FREEZE:
THE INCOMING AIRMASS WILL BRING AN ABRUPT REALITY CHECK. HIGH
TEMPERATURES ON SUNDAY WILL RUN 15 TO 20 DEGREES BELOW SEASONAL
AVERAGES—A REMARKABLE 30 TO 35-DEGREE DROP FROM FRIDAY'S HIGHS.
CALM WINDS AND CLEARING SKIES SUNDAY AND MONDAY NIGHTS WILL
SUPPORT STRONG RADIATIONAL COOLING, LEADING TO A WIDESPREAD HARD
FREEZE ACROSS ALL WESTERN MONTANA VALLEYS ON BOTH MONDAY AND
TUESDAY MORNINGS. PROTECTIVE MEASURES FOR AGRICULTURAL INTERESTS,
OUTDOOR PLUMBING, AND IRRIGATION SYSTEMS SHOULD BE COMPLETED AHEAD
OF THIS WEEKEND.
AVIATION
VFR CONDITIONS WILL CONTINUE ACROSS THE NORTHERN
ROCKIES TERMINALS THROUGH THURSDAY UNDER HIGH PRESSURE. LIGHT
TERRAIN DRIVEN WINDS AND MOSTLY CLEAR SKIES ARE EXPECTED, WITH
PASSING HIGH CLOUDS. STRONG VALLEY INVERSIONS WILL PROMOTE THE
DEVELOPMENT OF LOCALIZED MORNING MIST/FOG NEAR BODIES OF WATER,
INCLUDING AREA RIVERS AND LAKES.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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