605
FXUS65 KMSO 252014
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
214 PM MDT TUE AUG 25 2026
DISCUSSION
KEY MESSAGES:
- WARMEST TEMPERATURES TODAY AND WEDNESDAY.
- THUNDERSTORMS THIS AFTERNOON SOUTH OF INTERSTATE 90. EXPANDING
COVERAGE INTO ALL OF WESTERN MONTANA AND NORTH CENTRAL IDAHO ON
WEDNESDAY. MAIN THREATS WILL BE LIGHTNING AND GUSTY OUTFLOW
WINDS.
- PACIFIC NORTHWEST TROUGH BRINGS GUSTY WINDS LATER THIS WEEK AND
COOLER TEMPERATURES FOR THE WEEKEND.
HOT, DRY AND SMOKY CONDITIONS WILL CONTINUE THROUGH WEDNESDAY AS
HIGH PRESSURE REMAINS ANCHORED OVER WESTERN MONTANA. MONSOON
MOISTURE FROM THE DESSERT SOUTHWEST WILL BE EXPANDING NORTHWARDS,
INCREASING THE CHANCES FOR THUNDERSTORMS IN THE AFTERNOON AND
EVENING HOURS. THIS AFTERNOON, STORMS WILL BE MOST LIKELY ALONG
AND SOUTH OF INTERSTATE 90. THUNDERSTORM COVERAGE WILL EXPAND
NORTHWARDS TO THE CANADIAN BORDER BY WEDNESDAY AFTERNOON AND
EVENING. DUE TO THE VERY DRY LOW LEVELS OF THE ATMOSPHERE AND HIGH
CLOUD BASES, LITTLE PRECIPITATION IS EXPECTED TO ACCOMPANY STORMS.
GUSTY OUTFLOW WINDS WILL ALSO BE A CONCERN WITH STORMS, BETWEEN 30
TO 40 MPH TODAY AND POSSIBLY UP TO 50 MPH ON WEDNESDAY. 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. BREEZY CONDITIONS
ARE ANTICIPATED WITH ANOTHER ROUND OF THUNDERSTORMS, MAINLY ACROSS
WESTERN MONTANA. A SUBTLE DROP IN TEMPERATURES IS ANTICIPATED BY
FRIDAY AS A WEAK 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
HIGH PRESSURE WILL MAINTAIN WIDESPREAD VFR WEATHER
CONDITIONS ACROSS THE REGION TODAY, THOUGH WARMING TEMPERATURES
WILL SIGNIFICANTLY INCREASE DENSITY ALTITUDES, PARTICULARLY AT
HIGH-ELEVATION TERMINALS LIKE KBTM. DEGRADED SLANT-RANGE
VISIBILITY ALOFT IS ANTICIPATED DUE TO WILDFIRE SMOKE THROUGHOUT
THE AFTERNOON. SOME IMPROVEMENT IS POSSIBLE BY THIS EVENING,
HOWEVER VISIBILITY WILL LIKELY DEGRADE ONCE AGAIN LATE TONIGHT
INTO WEDNESDAY MORNING. MONSOONAL MOISTURE MOVING NORTHWARD WILL
INTRODUCE ISOLATED TO SCATTERED THUNDERSTORMS STARTING AROUND
25/2200Z, PARTICULARLY NEAR KSMN AND KBTM. THESE HIGH-BASED
STORMS WILL BE CAPABLE OF ERRATIC CONVECTIVE OUTFLOW WIND GUSTS OF
GENERALLY 30 TO 40 KNOTS NEAR STORM CORES.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...RED FLAG WARNING FROM 11 AM TO 7 PM PDT WEDNESDAY FOR
PALOUSE/HELLS CANYON.
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