140
FXUS65 KMSO 040837
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
237 AM MDT SAT JUL 4 2026
DISCUSSION
KEY MESSAGES:
- BREEZY AND WARM FOURTH OF JULY: CHOPPY CONDITIONS ON AREA
LAKES. WINDS CALMING AND SKIES CLEARING FOR THE EVENING.
- LOCALIZED HEAVY RAINFALL THREAT MONDAY AND TUESDAY WITH
SHOWERS AND STORMS.
TODAY AND SUNDAY (THE HOLIDAY WEEKEND): FOR THE FOURTH OF JULY, A
WEATHER SYSTEM PASSING TO OUR NORTH THROUGH BRITISH COLUMBIA WILL
FLATTEN THE UPPER-LEVEL RIDGE OVERHEAD, TRANSLATING TO AN
INCREASE IN WESTERLY WINDS THIS AFTERNOON. EXPECT SUSTAINED WINDS
OF 10 TO 20 MPH WITH GUSTS REACHING 20 TO 25 MPH. THIS WILL CREATE
CHOPPY CONDITIONS ON AREA LAKES, SO RECREATIONAL BOATERS SHOULD
EXERCISE CAUTION. FORTUNATELY, WINDS WILL DIMINISH BY DUSK,
LEAVING MOSTLY CLEAR SKIES AND CALM CONDITIONS FOR EVENING
FIREWORKS AND HOLIDAY FESTIVITIES.
SUNDAY PROMISES WARM AND MOSTLY STABLE CONDITIONS FOR THE MAJORITY
OF THE NORTHERN ROCKIES. THE MAIN EXCEPTION WILL BE ACROSS THE
SOUTHERN TIER OF OUR FORECAST AREA (SPECIFICALLY SOUTHWEST MONTANA
AND LEMHI COUNTY, ID), WHERE A SLOW NORTHWARD CREEP OF MOISTURE
WILL INTRODUCE ISOLATED AFTERNOON THUNDERSTORMS.
MONDAY AND TUESDAY: THE MOST IMPACTFUL WEATHER OF THE WEEK ARRIVES
MONDAY INTO TUESDAY. MODEL GUIDANCE HIGHLIGHTS A ROBUST SURGE OF
SUBTROPICAL MOISTURE PUSHING INTO THE REGION, DRIVING PRECIPITABLE
WATER (PWAT) VALUES WELL ABOVE NORMAL FOR EARLY JULY (NEAR OR
ABOVE 1.0 INCH). AS A MID-LEVEL DISTURBANCE TRACKS THROUGH THIS
MOISTURE-RICH ENVIRONMENT DURING PEAK AFTERNOON HEATING, IT WILL
TRIGGER ORGANIZED SHOWERS AND THUNDERSTORMS. BECAUSE OF THIS DEEP
MOISTURE PROFILE, ANY STORMS THAT DEVELOP WILL BE HIGHLY
EFFICIENT RAINFALL PRODUCERS.
WEDNESDAY THROUGH LATE WEEK: ONCE TUESDAY'S SYSTEM CLEARS, THE REMAINDER
OF THE WEEK LOOKS WARM AND RELATIVELY UNEVENTFUL. WE WILL RETURN
TO A MORE TYPICAL SUMMER PATTERN, WITH NEAR-DAILY CHANCES FOR
ISOLATED, POP-UP AFTERNOON THUNDERSTORMS LARGELY CONFINED TO THE
HIGHER TERRAIN OF SOUTHWEST MONTANA.
AVIATION
VFR CONDITIONS WILL PREVAIL ACROSS ALL NORTHERN ROCKIES
TERMINALS THROUGH TONIGHT. THE PRIMARY OPERATIONAL IMPACT TODAY
WILL BE AN INCREASE IN WESTERLY SURFACE WINDS AS A WEATHER SYSTEM
PASSING THROUGH BRITISH COLUMBIA FLATTENS THE UPPER-LEVEL RIDGE.
TERMINALS CAN EXPECT SUSTAINED WESTERLY WINDS OF 10 TO 15 KNOTS
WITH AFTERNOON GUSTS REACHING 20 KNOTS, WHICH MAY GENERATE
LOCALIZED MECHANICAL TURBULENCE FOR LIGHT AIRCRAFT ALONG AND NEAR
ELEVATED TERRAIN. THESE GUSTY WINDS WILL DECOUPLE AND RAPIDLY
DIMINISH BY DUSK, RESULTING IN LIGHT, TERRAIN-DRIVEN WINDS AND
MOSTLY CLEAR SKIES FOR THE OVERNIGHT HOURS INTO SUNDAY MORNING.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page