298
FXUS65 KMSO 301954
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
154 PM MDT SUN AUG 30 2026
DISCUSSION
KEY MESSAGES:
- UNSEASONABLY COLD TEMPERATURES WILL BRING FROST TO HIGH-
ELEVATION VALLEYS MONDAY MORNING, MARKING SOME OF THE COLDEST
TEMPERATURES SEEN SO FAR THIS YEAR.
- A BRIEF WARM-UP WITH DRY CONDITIONS AND LOW RELATIVE HUMIDITIES
IN THE TEENS TO LOW 20S IS EXPECTED EARLY NEXT WEEK.
- A SHORTWAVE DISTURBANCE ON WEDNESDAY WILL INCREASE THUNDERSTORM ACTIVITY
AND WINDS, POSING A NEAR-CRITICAL FIRE WEATHER RISK IN
SOUTHWEST MONTANA BEFORE PRECIPITATION ARRIVES.
- AN ACTIVE, COOLER WEATHER PATTERN WITH ABOVE-NORMAL PRECIPITATION
PROBABILITIES RETURNS LATE NEXT WEEK.
TODAY THROUGH TUESDAY:
CLEARING SKIES AND DRYING AIR TONIGHT WILL PROMOTE STRONG
RADIATIONAL COOLING, LEADING TO QUITE CHILLY MONDAY MORNING LOW
TEMPERATURES. THESE MORNING LOWS WILL BE SOME OF THE COLDEST
TEMPERATURES WE HAVE SEEN SO FAR THIS YEAR. WIDESPREAD FROST IS
EXPECTED IN HIGH-ELEVATION LOCATIONS, INCLUDING SEELEY LAKE,
GEORGETOWN, DRUMMOND TO BUTTE, AND DIXIE IDAHO, WHERE TEMPERATURES
WILL DROP INTO THE UPPER 20S TO LOW 30S. LOCALIZED LIGHT FROST
MAY ALSO REACH LOWER ELEVATION SPOTS LIKE STEVENSVILLE AND THE
WESTERN MISSOULA VALLEY.
TRANSITORY RIDGING WILL BRING WARM, DRY CONDITIONS MONDAY INTO
TUESDAY, PUSHING VALLEY HIGHS BACK INTO THE 80S. WITH THIS
RIDGE, A DRIER AIRMASS WILL SPREAD ACROSS THE REGION, DROPPING
AFTERNOON RELATIVE HUMIDITIES INTO THE WIDESPREAD TEENS TO LOW 20
PERCENT RANGE ON MONDAY. BY TUESDAY AFTERNOON AND EVENING, THE
RIDGE WILL BEGIN TO BREAK DOWN, YIELDING A SLIGHT INCREASE IN
WINDS, SCATTERED SHOWERS, AND ISOLATED THUNDERSTORMS. HIGH CLOUD
BASES SHOWERS ON TUESDAY AFTERNOON ELEVATING THE POTENTIAL FOR
STRONG, GUSTY OUTFLOW WINDS.
WEDNESDAY THROUGH LATE WEEK:
A NOTABLE SHORTWAVE DISTURBANCE WILL MOVE THROUGH THE AREA ON
WEDNESDAY, BRINGING A DEFINITE UPTICK IN WINDS AND MORE WIDESPREAD
THUNDERSTORM ACTIVITY, PARTICULARLY ACROSS SOUTHWEST MONTANA.
BEFORE THE PRECIPITATION ARRIVES WEDNESDAY AFTERNOON, THESE
STRONGER WINDS COMBINED WITH THE DRY CONDITIONS COULD CREATE NEAR-
CRITICAL FIRE WEATHER CONDITIONS IN SOUTHWEST MONTANA. AS THE
SYSTEM FULLY MOVES IN, THE SHOWERS AND THUNDERSTORMS WILL CARRY
THE POTENTIAL TO PRODUCE MODERATE TO HEAVY RAINFALL. WETTING RAIN
PROBABILITIES WILL INCREASE TO 50-70% ACROSS MUCH OF THE NORTHERN
ROCKIES DURING THIS TIMEFRAME.
LINGERING SHOWERS AND ELEVATED WINDS WILL PERSIST INTO THURSDAY
AND FRIDAY BEFORE WINDS TAPER OFF FOR THE WEEKEND. LOOKING INTO
THE WEEKEND, ENSEMBLE GUIDANCE SHOWS STRONG CONFIDENCE THAT A
TROUGH OF LOW PRESSURE WILL SIT OVER THE PACIFIC NORTHWEST. THIS
WILL MAINTAIN SOUTHWESTERLY FLOW OVER THE NORTHERN ROCKIES,
KEEPING TEMPERATURES SLIGHTLY BELOW SEASONAL AVERAGES AND FAVORING
AN ACTIVE REGIME WITH ABOVE-NORMAL PRECIPITATION PROBABILITIES
DUE TO DAILY SHOWER AND THUNDERSTORM ACTIVITY.
AVIATION
SHOWERS AND LOWERED CEILINGS WILL CONTINUE TO IMPACT
NORTHWEST MONTANA ESPECIALLY BETWEEN KGPI AND GLACIER NATIONAL
PARK, THAT WILL OBSCURED MOUNTAINS AT TIMES. GUSTY WESTERLY WINDS
WILL STEADILY DECREASE THROUGHOUT THE AFTERNOON INTO THE EVENING.
A RIDGE OF HIGH PRESSURE WILL BE BUILDING OVER THE REGION TONIGHT
INTO MONDAY. THIS RIDGE WILL ALLOW FOR THE DEVELOPMENT OF PATCHY
FOG AND LOW STRATUS. KGPI WILL HAVE THE BEST POTENTIAL OF
EXPERIENCING FOG.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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