794
FXUS65 KMSO 292000
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
200 PM MDT SAT AUG 29 2026
DISCUSSION
KEY MESSAGES:
- SHOWERS AND THUNDERSTORMS TODAY WITH FREQUENT
LIGHTNING, BRIEF HEAVY RAIN, AND ERRATIC GUSTS.
- ELEVATED POST-FRONTAL WINDS CREATING CHOPPY CONDITIONS ON
FLATHEAD LAKE THROUGH EARLY SUNDAY.
- UNSEASONABLY COLD TEMPERATURES (10 TO 15 DEGREES BELOW
AVERAGE) BRINGING HIGH- ELEVATION VALLEY FROST SUNDAY AND MONDAY
MORNINGS.
- BRIEF WARM-UP EARLY NEXT WEEK FOLLOWED BY ANOTHER
COOL, ACTIVE TROUGH LATE NEXT WEEK.
TODAY-SUNDAY:
NUMEROUS SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ACROSS NORTH-
CENTRAL IDAHO INTO NORTHWEST MONTANA AHEAD OF AN APPROACHING COLD
FRONT CURRENTLY POSITIONED ALONG THE IDAHO/WASHINGTON BORDER. THIS
FRONT WILL PUSH STEADILY ACROSS THE REGION THROUGH THIS AFTERNOON
AND EVENING. STORMS ALONG AND AHEAD OF THE BOUNDARY WILL BE
CAPABLE OF BRIEF MODERATE TO HEAVY RAINFALL, LIGHTNING, AND GUSTY,
ERRATIC OUTFLOW WINDS.
BEHIND THE FRONTAL PASSAGE, SURFACE WINDS WILL BECOME WIDESPREAD
AND REMAIN ELEVATED THROUGH THE OVERNIGHT HOURS INTO SUNDAY. THESE
GUSTY WINDS WILL GENERATE CHOPPY, HAZARDOUS BOATING CONDITIONS ON
FLATHEAD LAKE EARLY SUNDAY MORNING BEFORE DIMINISHING IN THE
AFTERNOON. MEANWHILE, THE MAIN CENTER OF THE LOW PRESSURE SYSTEM
WILL TRACK ALONG THE CANADIAN BORDER TONIGHT INTO SUNDAY, KEEPING
SHOWERS AND ISOLATED THUNDERSTORMS LINGERING ACROSS NORTHWEST
MONTANA.
THIS UNSEASONABLY COLD AIRMASS WILL PUSH TEMPERATURES ROUGHLY 10
TO 15 DEGREES BELOW AVERAGE FOR LATE AUGUST. CLEARER SKIES AND
COLD AIR DRAINAGE WILL ALLOW MORNING LOW TEMPERATURES TO DROP INTO
THE UPPER 20S TO LOW 30S ACROSS THE HIGH-ELEVATION VALLEYS OF
NORTH-CENTRAL IDAHO AND WESTERN MONTANA ON BOTH SUNDAY AND MONDAY
MORNINGS, RESULTING IN WIDESPREAD FROST.
MONDAY-LATE NEXT WEEK:
A TRANSIENT RIDGE OF HIGH PRESSURE WILL BUILD OVER THE REGION
MONDAY INTO TUESDAY, RETURNING WARM AND DRY CONDITIONS TO THE
NORTHERN ROCKIES. HOWEVER, LONG-RANGE MODEL GUIDANCE REMAINS IN
STRONG AGREEMENT THAT ANOTHER SIGNIFICANT TROUGH OF LOW PRESSURE
WILL DIG INTO THE PACIFIC NORTHWEST DURING THE LATTER PART OF NEXT
WEEK, USHERING IN ANOTHER STRETCH OF COOLER TEMPERATURES AND
ACTIVE WEATHER.
AVIATION
SHOWERS AND SCATTERED THUNDERSTORMS WILL MOVE ACROSS
REGIONAL TERMINALS THIS AFTERNOON ALONGSIDE AN ADVANCING COLD
FRONT. HEAVY DOWNPOURS MAY CAUSE BRIEF LOCALIZED IFR/MVFR
VISIBILITIES, ACCOMPANIED BY ERRATIC WIND GUSTS. WESTERLY SURFACE
WINDS WILL REMAIN ELEVATED OVERNIGHT INTO SUNDAY MORNING POST-
FRONT, GRADUALLY EASING BY SUNDAY AFTERNOON.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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