248
FXUS65 KMSO 301837
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
1237 PM MDT FRI MAY 30 2025
DISCUSSION
KEY MESSAGES:
- RECORD HEAT FOR THIS TIME OF YEAR EXPECTED ON SATURDAY
AFTERNOON/EVENING
- COOLER AND SHOWERY CONDITIONS NEXT WEEK
HIGH PRESSURE WILL CONTINUE TO STRENGTHEN INTO SATURDAY, BRINGING
GENERALLY SUNNY SKIES AND PUSHING VALLEY TEMPERATURES INTO THE
90S BY SATURDAY AFTERNOON. NUMEROUS DAILY RECORDS MAY BE BROKEN
ACROSS THE REGION, MANY OF WHICH DATE BACK TO 1986. IN FACT,
MISSOULA HAS A 28% CHANCE OF BREAKING ITS HOTTEST MAY DAY, 95F,
SET IN BOTH 1986 AND 1936. IT GOES WITHOUT SAYING THAT
TEMPERATURES THIS WARM ARE ABNORMAL FOR THIS EARLY IN THE YEAR,
AND THUS HEAT ADVISORIES HAVE BEEN ISSUED. IF YOU'RE PLANNING
OUTDOOR ACTIVITIES SATURDAY AFTERNOON, BE SURE TO STAY HYDRATED
AND TAKE BREAKS IN THE SHADE. ALSO REMEMBER RIVERS CONTINUE TO RUN
FAST AND COLD, INCREASING THE RISK OF HYPOTHERMIA AND ACCIDENTS.
A COLD FRONT WILL BEGIN TO MOVE THROUGH NORTH CENTRAL IDAHO
SATURDAY EVENING, STALLING ACROSS WEST-CENTRAL MONTANA SATURDAY
NIGHT. THIS WILL BEGIN TO INCREASE WINDS, PARTICULARLY NEAR THE
IDAHO PANHANDLE AND INTO NORTHWEST MONTANA, WITH WIND GUSTS UP TO
30 MPH LIKELY. THE HOT AND DRY CONDITIONS COMBINED WITH WIND WILL
ELEVATE THE FIRE WEATHER THREAT, ESPECIALLY IN THE LOWER VALLEYS
OF NORTH CENTRAL IDAHO. IT'S ALSO NOT OUT OF THE QUESTION TO SEE
AN ISOLATED THUNDERSTORMS DEVELOP SATURDAY EVENING NEAR THE CAMAS
PRAIRIE OF IDAHO, WITH GUSTY AND ERRATIC WINDS BEING THE MAIN
THREAT.
SUNDAY WILL OVERALL BE COOLER AND BREEZY AS THE COLD FRONT
CONTINUES TO MOVE THROUGH THE REGION INTO SOUTHWEST MONTANA. THE
FRONT WILL ELEVATE THE THREAT FOR STRONG THUNDERSTORMS TO DEVELOP,
MAINLY FROM LEMHI COUNTY EASTWARD INTO SOUTHWEST MONTANA. THE MAIN
THREAT WITH THESE STORMS WILL BE LIGHTNING AND GUSTY OUTFLOW WINDS
LOCALLY OVER 50 MPH.
FORECAST MODELS HAVE LARGELY ABANDONED THE IDEA OF A CLOSED LOW
PRESSURE SYSTEM MOVING THROUGH THE REGION EARLY NEXT WEEK.
INSTEAD, CONSENSUS IS FOR A BROAD TROUGH OVER THE PACIFIC
NORTHWEST WITH EMBEDDED SHORTWAVES MOVING ALONG THE CANADIAN
BORDER. WHILE TEMPERATURES WILL BE COOLER NEXT WEEK, PRECIPITATION
WILL LIKELY BE MORE SHOWERY IN NATURE AND MORE HIT OR MISS. THIS
PATTERN COULD ALSO PRODUCE PERIODS OF MORE BREEZY WINDS.
AVIATION
HIGH PRESSURE WILL REMAIN IN PLACE THROUGH SATURDAY,
WITH HOT CONDITIONS AND GENERALLY SUNNY SKIES. SATURDAY WILL BE
THE WARMEST DAY, WITH TEMPERATURES APPROACHING LOW TO MID 90S IN
MANY VALLEY LOCATIONS OF WESTERN MONTANA AND NORTH CENTRAL IDAHO.
DUE TO THE FORECASTED ABOVE NORMAL TEMPERATURES, HIGH DENSITY
ALTITUDE CONDITIONS ARE ANTICIPATED.
MSO WATCHES/WARNINGS/ADVISORIES
MT...HEAT ADVISORY FROM NOON TO 9 PM MDT SATURDAY FOR
FLATHEAD/MISSION VALLEYS...KOOTENAI/CABINET REGION...LOWER
CLARK FORK REGION...MISSOULA/BITTERROOT VALLEYS.
ID...HEAT ADVISORY FROM NOON SATURDAY TO MIDNIGHT PDT SATURDAY NIGHT
FOR LOWER HELLS CANYON/SALMON RIVER REGION...
OROFINO/GRANGEVILLE REGION.
HEAT ADVISORY FROM NOON TO 9 PM MDT SATURDAY FOR EASTERN LEMHI
COUNTY.
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