790
FXUS65 KMSO 081938
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
138 PM MDT WED JUL 8 2026
DISCUSSION
KEY MESSAGES:
- BREEZY WINDS 15 TO 25 MPH TODAY WILL CAUSE CHOPPY CONDITIONS ON
AREA LAKES. THUNDERSTORMS ARE POSSIBLE IN SOUTHWEST MONTANA
AND LEMHI COUNTY, WITH ABOUT A 5% CHANCE OF A SEVERE STORM.
- WARMEST TEMPERATURES OF THE SUMMER THIS WEEKEND THROUGH EARLY
NEXT WEEK.
- LOW RELATIVE HUMIDITY AND INCREASED WEST WINDS WILL RESULT IN
ELEVATED FIRE WEATHER CONCERNS ON SATURDAY AND SUNDAY.
RADAR RETURNS EARLY THIS MORNING SHOWED WANING CONVECTION OVER
NORTHWEST MONTANA SPAWNED BY AN ELONGATED TROUGH OF LOW PRESSURE
CENTERED OVER THE COAST OF BRITISH COLUMBIA. A SURFACE LOW SOUTH
AND EAST OF THIS TROUGH WILL PUSH A COLD FRONT THROUGH THE
NORTHERN ROCKIES THIS AFTERNOON, BRINGING INCREASED WINDS. EXPECT
CHOPPY CONDITIONS ON AREA LAKES, ESPECIALLY FLATHEAD LAKE THIS
AFTERNOON. INSTABILITY, AIDED BY THE COLD FRONT, WILL ALSO
INCREASE THIS AFTERNOON, BRINGING CHANCES FOR THUNDERSTORMS THIS
AFTERNOON AND EVENING. THE GEOGRAPHICAL FOCUS OF THUNDERSTORM
ACTIVITY WILL BE SOUTHWEST MONTANA AND LEMHI COUNTY. THE
COMBINATION OF INSTABILITY, SHEAR, AND MOISTURE WILL BE GREATEST
FOR EASTERN LEMHI AND SILVER BOW COUNTIES, WHICH IS WHERE THERE
WILL BE ABOUT A 5% CHANCE FOR A SEVERE THUNDERSTORM (58 MPH WINDS
AND/OR 1 INCH DIAMETER HAIL). THE REST OF SOUTHWEST MONTANA AND
LEMHI COUNTY SHOULD EXPECT THUNDERSTORMS TO PRODUCE GUSTY OUTFLOW
WINDS OF ABOUT 30-40 MPH, SMALL HAIL, BRIEF HEAVY RAIN, AND
LIGHTNING.
HIGH PRESSURE WILL CONTINUE TO BUILD OVER THE NORTHERN ROCKIES
GOING INTO THE WEEKEND. THUNDERSTORM ACTIVITY WILL DECREASE ON
THURSDAY. MODEL SOUNDINGS INDICATE SOME INCREASED INSTABILITY ON
FRIDAY EVENING, SO NOT RULING OUT ANOTHER ROUND OF (SUB-SEVERE)
THUNDERSTORMS THEN. TEMPERATURES WILL BOUNCE UP ON SATURDAY AND
STAY ELEVATED INTO EARLY NEXT WEEK. EXPECT DAYTIME HIGH
TEMPERATURES IN THE 90S FOR THE VALLEYS OF WESTERN MONTANA AND
TRIPLE DIGITS IN THE HELLS CANYON AND LOWER SALMON RIVER VALLEYS.
AN UPPER LEVEL JET STREAK WILL MOVE OVER THE NORTHERN ROCKIES ON
SATURDAY. STRONG WINDS, ALONG WITH ABNORMALLY HIGH TEMPERATURES
AND LOW RELATIVE HUMIDITY, WILL RESULT IN CONCERNS FOR NEAR-
CRITICAL FIRE WEATHER CONDITIONS IN SOUTHWEST MONTANA AND LEMHI
COUNTY ON SATURDAY AND SUNDAY.
NEXT WEEK WILL BRING AN INCREASE IN SUBTROPICAL MOISTURE. THIS
INFLUX OF MOISTURE WOULD ELEVATE THE RISK FOR WIDESPREAD, RAIN-
PRODUCING THUNDERSTORMS ACROSS WESTERN MONTANA AND NORTH-CENTRAL
IDAHO BY MIDWEEK, PROVIDING A DISTINCT CHANGE FROM THE DRY, AND
WINDY CONDITIONS ANTICIPATED OVER THE WEEKEND.
AVIATION
WEST TO NORTHWEST SURFACE WINDS WILL INCREASE ACROSS
NORTHWEST AND WEST-CENTRAL MONTANA TERMINALS, WITH SUSTAINED
SPEEDS OF 15 TO 25 MPH (15 TO 20 KNOTS) ANTICIPATED. MEANWHILE,
SCATTERED CONVECTIVE ACTIVITY IS EXPECTED ACROSS SOUTHWEST
MONTANA AND LEMHI COUNTY. THE PRIMARY THREAT TO AVIATION
OPERATIONS FROM THESE THUNDERSTORMS WILL BE ERRATIC, STRONG
OUTFLOW BOUNDARIES. HIGH- RESOLUTION GUIDANCE INDICATES A 25 TO
35 PERCENT PROBABILITY OF CONVECTIVE WIND GUSTS EXCEEDING 35
KNOTS NEAR FLIGHT ROUTES AND TERMINALS ALONG THE I-90 AND I-15
CORRIDORS SOUTH OF GARRISON JUNCTION, WITH A 5 PERCENT PROBABILITY
OF LOCALIZED GUSTS REACHING UP TO 50 KNOTS IN THE MOST INTENSE
CELLS.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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