136
FXUS65 KMSO 250952
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
352 AM MDT TUE AUG 25 2026
DISCUSSION
KEY MESSAGES:
- WARMEST TEMPERATURES TODAY AND WEDNESDAY.
- THUNDERSTORM CHANCES THIS AFTERNOON, INCREASING IN COVERAGE AND
NORTHWARD EXTENT FOR WEDNESDAY, BRINGING GUSTY OUTFLOW AND
LIGHTNING.
- PACIFIC NORTHWEST TROUGH BRINGS GUSTY WINDS LATER THIS WEEK AND
COOLER TEMPERATURES FOR THE WEEKEND.
HIGH PRESSURE WILL MAINTAIN A WARMING TREND ACROSS THE NORTHERN
ROCKIES TODAY AND TOMORROW WITH HIGH TEMPERATURES RUNNING ROUGHLY
10 DEGREES ABOVE SEASONAL AVERAGES. LIGHT SOUTHEASTERLY WINDS WILL
REROUTE SMOKE FROM FIRES TO THE EAST CAUSING LOCALIZED REDUCTIONS
IN AIR QUALITY AND MINOR IMPACTS TO LONG-RANGE VISIBILITY.
MONSOONAL MOISTURE WILL BEGIN TO SURGE NORTHWARD TODAY
REINTRODUCING SHOWER AND THUNDERSTORM CHANCES, PRIMARILY ACROSS
SOUTHWEST MONTANA AND CENTRAL IDAHO, EXTENDING AS FAR NORTHWARD AS
THE I-90 CORRIDOR. ERRATIC OUTFLOW WIND GUSTS OF 30 TO 40 MPH
WILL BE COMMONPLACE, WITH ISOLATED STRONGER GUSTS IN THE 50 MPH
RANGE POSSIBLE ACROSS SOUTHWEST MONTANA AND LEMHI COUNTY.
DEEPER MOISTURE WILL ENCOMPASS THE REGION BY WEDNESDAY, EXPANDING
THE COVERAGE OF CONVECTIVE SHOWER AND STORM CHANCES.
ENSEMBLE FORECAST GUIDANCE MAINTAINS HIGH CONFIDENCE IN AN
APPROACHING PACIFIC NORTHWEST UPPER-LEVEL TROUGH LATE THIS WEEK
INTO THE WEEKEND. THIS TRANSITION WILL INCREASE SYNOPTIC-SCALE
WESTERLY AND SOUTHWESTERLY WINDS FOR THURSDAY AND FRIDAY
INTRODUCING ANOTHER PROLONGED PERIOD OF ELEVATED FIRE WEATHER
CONDITIONS. THE INCOMING TROUGH WILL ALSO PROVOKE A LONGER-TERM
ACTIVE WEATHER PATTERN WITH MUCH COOLER TEMPERATURES FOR THIS
COMING WEEKEND.
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 TODAY DUE TO WILDFIRE SMOKE
THROUGHOUT THE AFTERNOON. MONSOONAL MOISTURE MOVING NORTHWARD WILL
INTRODUCE ISOLATED TO SCATTERED THUNDERSTORMS STARTING THIS
AFTERNOON 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...NONE.
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