712
FXUS65 KMSO 270758
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
158 AM MDT THU AUG 27 2026
DISCUSSION
KEY MESSAGES:
- SCATTERED THUNDERSTORMS TODAY, WITH LIGHTNING AND GUSTY
OUTFLOW WINDS BEING THE MAIN THREATS.
- A COLD FRONT ARRIVES SATURDAY, BRINGING COOLING TEMPERATURES,
GUSTY WESTERLY WINDS, AND PRECIPITATION, FOCUSED ALONG AND
SOUTH OF ABOUT I-90.
SATELLITE IMAGERY EARLY THIS MORNING INDICATES A CIRCULATION OF
LOW PRESSURE SPINNING OFF THE COAST OF SOUTHERN BRITISH COLUMBIA.
THIS FEATURE, ALONG WITH A RIDGE OF HIGH PRESSURE WITH ITS AXIS
JUST EAST OF THE CONTINENTAL DIVIDE, WILL KEEP THE NORTHERN
ROCKIES UNDER SOUTHWEST FLOW ALOFT GOING INTO THE WEEKEND. PACIFIC
MOISTURE FROM THE SOUTHWEST WILL BRING CHANCES FOR SHOWERS AND
THUNDERSTORMS AGAIN TODAY. MODEL SOUNDINGS SHOW ENOUGH INSTABILITY
FOR SHOWERS TO START AS EARLY AS THIS MORNING FOR LEMHI COUNTY
AND SOUTHWEST MONTANA. INSTABILITY INCREASES THIS AFTERNOON, WHEN
THUNDERSTORM ACTIVITY WILL SPREAD FURTHER NORTH. HIGH RESOLUTION
MODELS INDICATE CHANCES FOR THUNDERSTORMS ACROSS NORTH-CENTRAL
IDAHO AND NORTHWEST AND WEST-CENTRAL MONTANA. A DRY LOWER
ATMOSPHERE WILL KEEP RAIN AMOUNTS ON THE LOW SIDE, SO PRIMARY
IMPACTS WILL BE GUSTY OUTFLOW WINDS (30-50 MPH) AND FREQUENT
LIGHTNING. EXPECT WINDY CONDITIONS THIS AFTERNOON ACROSS MUCH OF
THE NORTHERN ROCKIES AS THE PACIFIC LOW MOVES INLAND AND AN UPPER
LEVEL JET STREAK BECOMES SITUATED OVER CENTRAL IDAHO AND WESTERN
MONTANA. SOUTHERN IDAHO COUNTY, AS WELL AS LEMHI COUNTY AND
SOUTHWEST MONTANA WILL BE THE BREEZIEST, AS GUSTS FROM THE
SOUTHWEST REACH ABOUT 30 MPH THIS AFTERNOON.
AS THE LOW TRAVERSES THE CANADIAN BORDER ON FRIDAY, IT WILL PUSH
A COLD FRONT ACROSS THE NORTHERN ROCKIES. DAYTIME HIGH
TEMPERATURES WILL DROP DOWN TO THE UPPER 70S TO LOW 80S FOR
MONTANA VALLEYS AND LOW 90S FOR THE LOWER VALLEYS OF WESTERN
IDAHO. WIDESPREAD PRECIPITATION ARRIVES ON SATURDAY AS THE LOW
MOVES FURTHER INLAND. EXPECT MORE FALL-LIKE TEMPERATURES AS THE
WEEKEND PROGRESSES. AS FAR AS PRECIPITATION GOES, CHANCES FOR
WETTING RAIN (MORE THAN 0.10 IN) BY SUNDAY WILL BE ABOUT 70-80%
FOR WEST-CENTRAL AND SOUTHWEST MONTANA, AS WELL AS LEMHI COUNTY.
CHANCES WILL BE SLIGHTLY BETTER GOING EAST, AND WORSE FURTHER WEST
AND NORTH, WITH LITTLE TO NO PRECIPITATION FOR FAR NORTHWEST
MONTANA. TEMPERATURES REBOUND EARLY NEXT WEEK, WHILE ENSEMBLE
SOLUTIONS ARE INDICATING MORE UNSETTLED WEATHER LATER IN THE WEEK.
AVIATION
GUSTY WINDS AND CHANCES FOR THUNDERSTORMS WILL BE THE
MAIN IMPACTS TO AVIATION TODAY. SOUTHWEST WINDS GUSTING TO 20-30
KNOTS WILL INCREASE THIS AFTERNOON AT ALL AIRFIELDS. CHANCES FOR
THUNDERSTORMS WILL ALSO INCREASE BY ABOUT 27/2000Z. MODEL SOUNDINGS
SHOW ENOUGH INSTABILITY FOR ISOLATED SHOWERS TO START AS EARLY AS
THIS MORNING FOR KSMN AND KBTM. THUNDERSTORM COVERAGE THIS
AFTERNOON WILL BE PRIMARILY OVER KSMN AND KBTM. WHILE THE LOWER
ATMOSPHERE REMAINS DRY, THE PRIMARY THREATS FROM TODAY’S STORMS
WILL BE GUSTY OUTFLOW WINDS OF 30-40 KNOTS AND FREQUENT LIGHTNING.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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