585
FXUS65 KMSO 230906
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
306 AM MDT SUN AUG 23 2026
DISCUSSION
KEY MESSAGES:
- COLD FRONT BRINGS COOLER TEMPERATURES ALONGSIDE GUSTY WESTERLY
WINDS, DRY AIR, AND INCREASED FIRE WEATHER TODAY.
- RIDGE OF HIGH PRESSURE REBUILDS EARLY THIS UPCOMING WEEK WITH
A WARMING TREND.
A COLD FRONT WILL CONTINUE TO SWEEP ACROSS THE NORTHERN ROCKIES
TODAY. A FEW LINGERING SHOWERS OR ISOLATED THUNDERSTORMS WILL
REMAIN POSSIBLE THIS MORNING BEFORE A SIGNIFICANTLY DRIER AIRMASS
PUSHES PRECIPITATION THREATS EASTWARD FROM THE I-15 CORRIDOR INTO
CENTRAL MONTANA. THE FRONTAL PASSAGE WILL PROVIDE A BRIEF RESPITE
FROM THE HEAT, DROPPING DAYTIME HIGHS 10 TO 15 DEGREES FROM WHAT
WAS OBSERVED ON SATURDAY BRINGING TEMPERATURES CLOSER TO SEASONAL
AVERAGES. DEEP BOUNDARY LAYER MIXING WILL TAP INTO STRONGER
MOMENTUM ALOFT AND DRIVE GUSTY SURFACE WESTERLY WINDS ACROSS THE
REGION THROUGH EARLY THIS EVENING. THE COMBINATION OF THESE
STRONGER SYNOPTIC WINDS AND A VERY DRY POST-FRONTAL AIRMASS WILL
CREATE ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS TODAY. WINDS
WILL GRADUALLY DECOUPLE AND DIMINISH AFTER SUNSET TONIGHT.
A RIDGE OF HIGH PRESSURE RAPIDLY REBUILDS OVER THE REGION EARLY
THIS UPCOMING WEEK, MARKING A RETURN TO STABLE AND WARM IF NOT HOT
CONDITIONS. A MOSTLY DRY FORECAST CARRIES US THROUGH AT LEAST
WEDNESDAY ASIDE FROM NEAR-DAILY CHANCES FOR AFTERNOON SHOWERS AND
ISOLATED THUNDERSTORMS IN LEMHI COUNTY AND SOUTHWEST MONTANA.
LOOKING TOWARD THE MID-TO-LATE PORTION OF THE WORKWEEK, ENSEMBLE
GUIDANCE CONTINUES TO IDENTIFY A RETURN TO MORE ACTIVE WEATHER
WITH ANOTHER MODERATING COOLDOWN, AFTERNOON BREEZES, AND
INCREASING SHOWER AND STORM CHANCES.
AVIATION
LINGERING MORNING SHOWERS OR ISOLATED THUNDERSTORMS
WILL QUICKLY DIMINISH AS A COLD FRONT SWEEPS ACROSS THE REGIONAL
AIRSPACE TODAY. A SIGNIFICANTLY DRIER AIRMASS WILL MIX INTO THE
REGION MARKING A RETURN OF WIDESPREAD VFR WEATHER CONDITIONS. DEEP
MIXING WILL PRODUCE STRONG SYNOPTIC-SCALE WESTERLY WINDS BETWEEN
15 AND 30 KNOTS ACROSS ALL TERMINALS FROM LATE MORNING THROUGH THE
EVENING HOURS. WINDS DECOUPLE AND RELAX CLOSE TO AND AFTER SUNSET.
MSO WATCHES/WARNINGS/ADVISORIES
MT...RED FLAG WARNING UNTIL 6 AM MDT EARLY THIS MORNING FOR
KOOTENAI...WEST LOLO.
RED FLAG WARNING FROM 1 PM THIS AFTERNOON TO 8 PM MDT THIS
EVENING FOR DEERLODGE/WEST BEAVERHEAD.
ID...NONE.
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