377
FXUS65 KMSO 111000
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
400 AM MDT MON MAY 11 2026
DISCUSSION
KEY MESSAGES:
- HOT AND DRY WEATHER THROUGH WEDNESDAY, WITH TEMPERATURES REACHING
INTO THE MID 80S TO LOW 90S BY TUESDAY AND WEDNESDAY.
- SPRING THUNDERSTORMS WEDNESDAY AND THURSDAY; MAIN HAZARDS WILL
BE LIGHTNING AND ERRATIC/GUSTY OUTFLOW WINDS.
- THIS WEEKEND COULD BE A SHOCK TO THE SYSTEM AFTER A WARM START
TO THE WEEK. A COOLDOWN IS EXPECTED, AND EVEN A CHANCE FOR SOME
MOUNTAIN SNOWFALL!
NEAR-RECORD WARMTH IS POSSIBLE BY TUESDAY AND WEDNESDAY AS HIGH
TEMPERATURES CLIMB INTO THE 80S AND 90S ACROSS THE REGION. IN
WESTERN MONTANA, SEVERAL VALLEYS OF NORTHWEST MONTANA HAVE A
HIGHER PROBABILITY FOR HITTING 90 DEGREES (I.E. ST. REGIS, LIBBY
AND TROUT CREEK). IN IDAHO THE LOWER VALLEYS WILL BE IN THE
90S...EVEN SALMON COULD REACH 90 DEGREES ON TUESDAY WHICH BREAK
THE PREVIOUS DAILY RECORD OF 89 SET BACK IN 1993.
THE EVOLUTION OF THE WEATHER FEATURES FOR WEDNESDAY AND BEYOND
HAVE BEEN VERY DIFFICULT TO PIN DOWN. EVEN WPC'S LONG-RANGE
DISCUSSION THIS MORNING MENTIONED "ABYSMAL AGREEMENT BOTH RUN-TO-
RUN AND WITHIN THE LARGER MODELING SUITE AS A WHOLE". SO DESPITE
THE DIFFERENCES, THERE IS STILL A CHANCE FOR SHOWERS AND
THUNDERSTORMS ON WEDNESDAY. CONFIDENCE IS HIGHER THAT TEMPERATURES
WILL BE MUCH COOLER ACROSS NORTH-CENTRAL IDAHO, BUT WESTERN
MONTANA MAY BE THE BATTLEGROUND FOR TEMPERATURES AND WIND. THE
FORECAST CONTINUES TO CARRY TEMPERATURES IN THE 80S FROM LIBBY
SOUTH AND EAST. IF THE TROUGH ENDS UP SWINGING ACROSS NORTHERN
IDAHO AND WESTERN MONTANA, LIKE THE ECMWF IS DEPICTING, THEN THE
COLD FRONT PASSAGE COULD BE A LOT STRONGER WEDNESDAY AFTERNOON AND
WITH A BETTER CHANCE FOR PRECIPITATION AREA-WIDE. RECREATION ON
AREA LAKES COULD BE IMPACTED BUT GUSTY WINDS WITH THE FRONT, BUT
ALSO ANY SHOWER/STORM ACTIVITY THAT MAY DEVELOP. IF THE TROUGH
ENDS UP MOVING SLOWER AND TRACKING ACROSS NORTHERN CALIFORNIA INTO
NEVADA, THEN THE FRONT WILL BE WEAKER, HIGHS COULD BE WARMER, AND
THE BETTER CHANCE FOR PRECIPITATION WILL BE ACROSS NORTH- CENTRAL
IDAHO INTO SOUTHWEST MONTANA.
TRYING TO MAKE SENSE OUT OF THE CHAOTIC PATTERN TOWARDS THE
WEEKEND...THE ENSEMBLE CLUSTERS ALL SEEM TO DEPICT A TROUGH
PATTERN ENSUING THIS WEEKEND. THE COLD TROUGH THAT IS USUALLY
SITUATED OVER THE GULF OF ALASKA MAY GET DISLODGED AND MOVE DOWN
HERE. TEMPERATURE FORECASTS CONTINUE TO TREND COLDER WITH HIGHS IN
THE 60S SATURDAY AND SUNDAY. THIS WOULD BE AN UNSTABLE AND SHOWERY
SETUP WITH SNOW LEVELS FALLING DOWN TO 4500 TO 5000 FEET. BACKCOUNTRY
CONDITIONS COULD END UP FEELING LIKE WINTER AGAIN. THE PATTERN
LOOKS UNSETTLED GOING INTO THE FOLLOWING WEEK!
AVIATION
VFR CONDITIONS WILL PREVAIL ACROSS THE NORTHERN ROCKIES
AIRSPACE THROUGH TUESDAY UNDER THE INFLUENCE OF A BUILDING UPPER-
LEVEL RIDGE. BREEZY WESTERLY SURFACE WINDS ARE EXPECTED ACROSS
THE REGION TODAY WITH POSSIBLE GUSTS OF 20 TO 25 KNOTS ESPECIALLY
TOWARDS THE DIVIDE, WHICH MAY INTRODUCE LOCALIZED MECHANICAL
TURBULENCE. ASIDE FROM THE WINDS, THE PRIMARY OPERATIONAL IMPACT
WILL BE STEADILY INCREASING DENSITY ALTITUDES AS EARLY-SEASON HEAT
DEVELOPS, REMAINING A PERSISTENT CONCERN INTO MID WEEK.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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