048
FXUS65 KMSO 260807
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
207 AM MDT WED AUG 26 2026
DISCUSSION
KEY MESSAGES:
- THUNDERSTORMS THIS AFTERNOON ACROSS WESTERN MONTANA AND NORTH
CENTRAL IDAHO. MAIN THREATS WILL BE LIGHTNING AND GUSTY OUTFLOW
WINDS. THUNDERSTORMS AGAIN ON THURSDAY, WITH GEOGRAPHICAL
FOCUS MORE ON SOUTHWEST MONTANA.
- A COLD FRONT WILL ARRIVE LATE FRIDAY INTO SATURDAY, BRINGING
GUSTY WESTERLY WINDS, DRIER AIR, AND ELEVATED FIRE WEATHER
CONDITIONS.
- THERE IS INCREASING CONFIDENCE IN A COOLER, BREEZIER PATTERN
THIS WEEKEND
A RIDGE OF HIGH PRESSURE WITH ITS AXIS JUST EAST OF THE NORTHERN
ROCKIES WILL DRAW MOISTURE UP FROM THE SOUTHWEST AND INTO WESTERN
MONTANA AND NORTH-CENTRAL IDAHO TODAY. HOT, DRY CONDITIONS WILL
PERSIST. INSTABILITY WILL INCREASE WITH AFTERNOON HEATING,
ALLOWING SCATTERED, HIGH-BASED SHOWERS AND THUNDERSTORMS TO
DEVELOP. MODEL SOUNDINGS INDICATE A DRY LOWER ATMOSPHERE. AS A
RESULT, THE PRIMARY THREATS FROM THESE STORMS WILL BE STRONG,
ERRATIC OUTFLOW WINDS AND LIGHTNING. THUNDERSTORM ACTIVITY WILL
INITIATE OVER SOUTHWEST MONTANA AND CENTRAL IDAHO THIS AFTERNOON
BEFORE TRACKING NORTHWARD TOWARD THE I-90 CORRIDOR AND NORTHWEST
MONTANA BY THIS EVENING. THE COMBINATION OF MOSTLY DRY STORMS,
LIGHTNING, AND GUSTY WINDS WILL ELEVATE THE POTENTIAL FOR NEW FIRE
STARTS. ON THURSDAY, THE HIGH PRESSURE RIDGE BEGINS TO BREAK DOWN
AS A TROUGH OF LOW PRESSURE APPROACHES FROM THE WEST. EXPECT BREEZY
CONDITIONS WITH ANOTHER ROUND OF THUNDERSTORMS, MAINLY ACROSS
SOUTHWEST MONTANA. A SUBTLE DROP IN TEMPERATURES ARRIVES FRIDAY
AS A COLD FRONT MOVES THROUGH THE REGION. GUSTY WINDS, DRY
CONDITIONS, AND LINGERING THUNDERSTORMS WILL KEEP FIRE WEATHER
CONDITIONS ELEVATED BOTH DAYS.
THE WEEKEND WILL TREND SIGNIFICANTLY COOLER WITH TEMPERATURES AT
OR EVEN SLIGHTLY BELOW NORMAL. THERE ARE STILL A FEW MODELS
SHOWING A MORE SIGNIFICANT LOW PRESSURE SYSTEM MOVING THROUGH
NORTHWEST MONTANA, BUT THE MAJORITY OF MODELS SOLUTIONS ARE
TRENDING MORE TOWARDS AN OPEN WAVE, WHICH DECREASES THE CHANCE OF
PRECIPITATION. THERE IS STILL POTENTIAL TO SEE SHOWER AND
THUNDERSTORM ACTIVITY IN THIS PATTERN, BUT THIS WOULD BE MORE
FOCUSED ACROSS SOUTHWEST MONTANA AND LEMHI COUNTY.
AVIATION
AFTERNOON THUNDERSTORMS WILL BE THE BIGGEST IMPACT TO
AVIATION TODAY AND THURSDAY. CONVECTION WILL INITIALLY DEVELOP
AROUND 26/2000Z NEAR KSMN AND KBTM, EVENTUALLY SPREADING NORTHWARD
TOWARD KMSO, KHRF, AND KGPI THIS EVENING. THE PRIMARY AVIATION
HAZARDS WITH THESE HIGH-BASED STORMS WILL BE LOCALIZED, ERRATIC
OUTFLOW WIND GUSTS OF 35 TO 45 KNOTS. FLIGHT CATEGORIES WILL
LARGELY REMAIN VFR, THOUGH BRIEF MVFR CONDITIONS AND LOCALIZED
MOUNTAIN OBSCURATIONS ARE POSSIBLE DURING DIRECT THUNDERSTORM
IMPACTS.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...RED FLAG WARNING FROM 11 AM THIS MORNING TO 7 PM PDT THIS
EVENING FOR PALOUSE/HELLS CANYON.
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