204
FXUS65 KMSO 061757
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
1157 AM MDT MON JUL 6 2026
DISCUSSION
KEY MESSAGES:
- LOCALIZED HEAVY RAINFALL, GUSTY OUTFLOW WIND, LIGHTNING AND
SMALL HAIL THREAT TODAY WITH SHOWERS AND STORMS.
- BREEZY WINDS 15 TO 25 MPH ON WEDNESDAY COULD CAUSE CHOPPY
LAKES. A FEW THUNDERSTORMS ARE POSSIBLE.
- WARMEST TEMPERATURES OF THE SUMMER THIS WEEKEND THROUGH EARLY
NEXT WEEK.
A 5 MILLIBAR PRESSURE GRADIENT BETWEEN MISSOULA AND HELENA HAS
RESULTED IN EASTERLY WINDS GUSTING TO AROUND 25 MPH ACROSS WESTERN
MONTANA LATE THIS MORNING.
LATEST HIGH-RESOLUTION MODELS DEPICT THE FOCUS OF THUNDERSTORMS
OCCURRING FROM SOUTHEASTERN IDAHO COUNTY TO POINTS EAST AND SOUTH
OVER LEMHI COUNTY THIS AFTERNOON. THE EARLY NATURE OF THE
SHORTWAVE HAS BROUGHT IN A LOT OF CLOUD COVER WHICH COULD
INITIALLY LIMIT INSTABILITY. CURRENT SATELLITE IMAGERY SHOWS SOME
BREAKS IN THE CLOUDS LOCATED SOUTH OF THE SALMON RIVER CORRIDOR.
THE GREATEST PROBABILITY FOR STORMS PRODUCING HEAVY RAIN IS OVER
THE BITTERROOT AND SAPPHIRE MOUNTAIN RANGES. NEAR THE OLD DALY
BURN SCAR OR NEAR SKALKAHO PASS, THE PROBABILITY IS AROUND 55%. IF
A STORM WERE TO HIT THIS PARTICULAR SPOT, THEN THERE COULD BE SOME
RUNOFF ISSUES. THE STORM MOTION OF THE STORMS WILL BE FAIRLY
QUICK, MOVING OFF TO THE NORTHEAST BETWEEN 20 AND 25 MPH WHICH
WOULD LIMIT THE AMOUNT OF RAIN. THERE COULD BE ENOUGH SHEAR AND
INSTABILITY THAT A FEW STORMS COULD PRODUCE 0.25 TO 0.75 INCH
HAIL.
MODELS HAVE TRENDED DOWN WITH SHOWER ACTIVITY ON TUESDAY. A
DEPARTING SHORTWAVE WITH BUILDING RIDGE USUALLY DOESN'T BODE WELL
FOR THUNDERSTORMS. THERE IS STILL A SLIGHT CHANCE FOR STORMS OVER
THE DIVIDE.
A WESTERLY WAVE WILL BRING BREEZY CONDITIONS ACROSS THE REGION ON
WEDNESDAY, ALONG WITH A CHANCE FOR THUNDERSTORMS ACROSS SOUTHWEST
MONTANA. WESTERLY WINDS BETWEEN 15 AND 25 MPH COULD BRING CHOPPY
CONDITIONS TO AREA LAKES. ZONAL FLOW CONTINUES ON THURSDAY AND
COULD BRING SIMILAR WINDS TO THE REGION.
THE HEAT RIDGE STARTS TO BUILD ACROSS THE FOUR CORNERS OF THE
COUNTRY STARTING FRIDAY. WE'LL BE UNDER MOSTLY DRY, SOUTHWEST FLOW
WITH TEMPERATURES CLIMBING INTO THE 80S AND 90S, AND EVEN UP TO
102 IN THE HELLS CANYON AND SALMON RIVER VALLEY IN NORTH-CENTRAL
IDAHO. THERE COULD BE JUST ENOUGH INSTABILITY FOR A FEW SHOWERS OR
THUNDERSTORMS TO FORM OVER THE TERRAIN IN SOUTHWEST MONTANA.
THE HOTTER AIR FROM UTAH AND SOUTHERN IDAHO PUSHES UP HERE OVER
THE WEEKEND. THE GREATER PROBABILITIES(70-80+%) FOR 100 TO 105
DEGREES ARE SITUATED IN THE LOWER VALLEYS OF NORTH- CENTRAL IDAHO
AND LEMHI COUNTY THROUGH MONDAY. DURING THIS PERIOD, MAKE SURE
YOU DRINK PLENTY OF WATER, TAKE FREQUENT BREAKS IN THE AFTERNOON
HOURS AND DO NOT LEAVE CHILDREN OR PETS IN VEHICLES.
AVIATION
SOME CLEARING IS OCCURRING AT MIDDAY ON THE SOUTH
SIDE OF THE HIGH/MID LEVEL CLOUD SHIELD THAT HAS KEPT DOWN
HEATING THIS MORNING FOR AREAS I-90 SOUTHWARD. SHOWER/THUNDERSTORM
ACTIVITY IS EXPECTED TO INCREASE DUE TO THE DIFFERENTIAL HEATING
NEAR THE CLEARING AND DYNAMIC FORCING AHEAD OF A DECENT SHORTWAVE.
SEVERAL ROUNDS OF SHOWERS/THUNDERSTORMS ARE LIKELY ACROSS
SOUTHWEST/WEST-CENTRAL MONTANA AND NORTH-CENTRAL IDAHO INTO EARLY
EVENING WITH ACTIVITY SHIFTING INTO NORTHWEST MONTANA OVERNIGHT
(MAINLY ALONG AND EAST OF US-93). TERMINALS DIRECTLY IMPACTED BY
THESE STORMS CAN EXPECT BRIEF MVFR/IFR CONDITIONS IN HEAVY
DOWNPOURS, ALONG WITH FREQUENT LIGHTNING AND TERRAIN OBSCURATION.
ERRATIC CONVECTIVE OUTFLOW GUSTS OF 25 TO 35 KNOTS ARE POSSIBLE.
THERE IS A POTENTIAL FOR A SOUTHERLY WIND SURGE TRACKING NORTH
THROUGH THE BITTERROOT AND MISSOULA VALLEYS (DIRECTLY IMPACTING
KMSO) BETWEEN 23Z AND 01Z WITH GUSTS OF 25-30 KTS BUT HIGH
RESOLUTION GUIDANCE IS LESS CONFIDENT COMPARED TO EARLIER RUNS.
SHOWERS AND ISOLATED THUNDERSTORMS WILL LINGER EARLY TUESDAY
MORNING, PARTICULARLY ACROSS NORTHWEST MONTANA (KGPI) AND ALONG
THE CONTINENTAL DIVIDE. THE LOWER LEVELS OF THE ATMOSPHERE DRY OUT
ON TUESDAY BEHIND THE DEPARTING DISTURBANCE BUT ISOLATED
AFTERNOON THUNDERSTORMS ARE STILL EXPECTED, FOCUSING PRIMARILY
NEAR THE CONTINENTAL DIVIDE.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page