142
FXUS65 KMSO 110739
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
139 AM MDT FRI SEP 11 2026
DISCUSSION
KEY MESSAGES:
- NORTHEAST WINDS FRIDAY NIGHT THROUGH SATURDAY WILL CREATE
CHOPPY CONDITIONS ON AREA LAKES.
- A CUTOFF LOW PRESSURE SYSTEM BRINGS WIDESPREAD RAIN, WITH SNOW
ABOVE 6,000 FEET SATURDAY NIGHT THROUGH MONDAY MORNING.
SHOWERS AND THUNDERSTORMS WILL CONTINUE OVER WESTERN MT THROUGH
NOON, THESE SHOWERS ARE POWERED BY JET STREAM ENERGY ALOFT.
AFTERNOON SHOWERS WILL CONTINUE BUT MAINLY IN THE MOUNTAINS EAST
OF US-93, OROGRAPHIC UPLIFT WILL BECOME THE MAIN INSTIGATOR.
FRIDAY EVENING AN EASTERLY GRADIENT DEVELOPS OVER THE REGION AND
WINDS SLOWLY TURN EAST NORTHEASTERLY. GENERALLY, GUSTS UP TO 30
MPH IN THE GAPS SHOULD BE THE STRONGEST WINDS. FOR BOATERS GOING
OUT EARLY SATURDAY PREPARE FOR CHOPPY CONDITIONS ON AREA LAKES.
THIS IS A COOLER AIR MASS, THURSDAY WAS THE WARMEST DAY WITH BOTH
FRIDAY AND SATURDAY 8 TO 12 DEGREES COOLER. THEN AS THE CLOSED LOW
MOVES OVER THE REGION SUNDAY, UNDER THE CORE OF LOW PRESSURE TEMPERATURES
MAY COOL AN ADDITIONAL 10 TO 15 DEGREES. SNOW LEVELS THAT ARE
8000-9000 FEET ON SATURDAY, WILL LOWER TO AROUND 7000 FEET ON
SUNDAY. HISTORICALLY UNDER THE CORE OF LOW PRESSURE SNOW LEVELS
ARE AN ADDITIONAL 1000 FEET LOWER, TO AROUND 6000 FEET ON SUNDAY
EVENING, DUE TO DYNAMIC COOLING PROCESSES. STILL IT IS SEPTEMBER
AND THE MAIN MESSAGE FOR SNOW IS THE SAME FOR RAIN. SUNDAY INTO
MONDAY IN THE BACK COUNTRY WILL BE WET AND RAW, UNPREPARED OUTDOOR
ENTHUSIASTS MAY ENCOUNTER HYPOTHERMIA INDUCING CONDITIONS.
THE MODELS HAVE CONTINUED A NORTHWARD TREND IN THE CORE OF BEST
PRECIPITATION, STILL I-90 AND NORTHWARD INCLUDING ALL OF IDAHO AND
CLEARWATER COUNTIES ID, HAVE A 80 TO 90% CHANCE OF WIDESPREAD 0.25
OR MORE PRECIPITATION. SOUTH AND WEST TO BUTTE, THAT CHANCE LOWERS
TO 30 TO 40%. CLOSED LOWS ARE NOTORIOUS FOR WOBBLING AT THE LAST
MINUTE, SO IF TOTAL PRECIPITATION IS IMPORTANT TO YOUR ACTIVITIES
STAY ABREAST OF FUTURE FORECASTS. UP TO 1 INCH IN THE HIGHEST
TERRAIN OF IDAHO AND CLEARWATER COUNTIES IS STILL POSSIBLE, ALONG
WITH THE MISSION AND SEELEY SWAN MOUNTAINS.
AVIATION
SHOWERS AND THUNDERSTORMS WILL END AROUND 11/1800Z AT
KMSO, KHRF, AND KGPI IF ANY REMAIN AFTER SUNRISE. AN EASTERLY
GRADIENT DEVELOPS OVER THE REGION BY 11/1800Z STARTING AT KGPI,
EVENTUALLY EXPANDING THROUGHOUT THE AFTERNOON AND EVENING TO ALL
TAF SITES. THE NEXT ROUND OF SHOWERS AND THUNDERSTORMS WILL BEGIN
TO AFFECT TERMINALS AFTER 12/2000Z.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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