439
FXUS65 KMSO 291857
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
1257 PM MDT THU MAY 29 2025
DISCUSSION
KEY MESSAGES:
- FOR THIS EVENING, BREEZY WEST WINDS WITH COLD FRONT PASSAGE. A
FEW STRONG THUNDERSTORMS CAPABLE OF OUTFLOW WINDS TO 50 MPH
POSSIBLE, MAINLY ACROSS SOUTHWEST MONTANA.
- HOT AND DRY FRIDAY THROUGH SATURDAY, WITH RECORD HEAT FOR THIS
TIME OF YEAR BY SATURDAY.
- COOLER AND SHOWERY FOR THE FIRST HALF OF NEXT WEEK.
A COLD FRONT IS STILL ANTICIPATED TO MOVE THROUGH NORTH CENTRAL
IDAHO AND WESTERN MONTANA THIS EVENING. THE FRONT WILL BRING
BREEZY SOUTHWEST TO WEST WINDS FOR MOST LOCATIONS, WITH GUSTS UP
TO 30 MPH. IN ADDITION, THUNDERSTORMS ARE ANTICIPATED TO DEVELOP
AHEAD OF AND WITH THE FRONT, MAINLY FOCUSED ALONG AND EAST OF
HIGHWAY 93. A FEW STORMS MAY BECOME STRONG, PRIMARILY ACROSS
SOUTHWEST MONTANA, WHERE THE MAIN THREAT WILL BE GUSTY OUTFLOW
WINDS UP TO 50 MPH.
HIGH PRESSURE QUICKLY REBOUNDS OVER THE REGION FRIDAY INTO
SATURDAY, WITH TEMPERATURES REACHING INTO THE UPPER 80S TO MID 90S
BY SATURDAY. THIS IS ROUGHLY 15 TO 20 DEGREES ABOVE NORMAL FOR
THIS TIME OF YEAR AND IS RELATIVELY ABNORMAL FOR 90 DEGREE
TEMPERATURES TO BE REACHED THIS EARLY IN THE YEAR. HEAT ADVISORIES
HAVE BEEN ISSUED FOR MANY VALLEY LOCATIONS OF WESTERN MONTANA AND
NORTH CENTRAL IDAHO. THOSE RECREATING OUTSIDE SATURDAY AFTERNOON
SHOULD TAKE PRECAUTIONS, AND KEEP IN MIND THAT RIVERS AND STREAMS
CONTINUE TO RUN FAST AND COLD.
ANOTHER COLD FRONT WILL MOVE THROUGH SATURDAY NIGHT INTO SUNDAY,
BRINGING A SLIGHT COOL DOWN AND BREEZY WINDS.
REGARDING THE WEATHER SYSTEM NEXT WEEK, RECENT FORECAST MODELS
HAVE BEEN TRENDING AWAY FROM A CLOSED LOW SCENARIO AND MORE
TOWARDS AN OPEN TROUGH MOVING THROUGH THE REGION. CONFIDENCE IS
HIGH TEMPERATURES WILL BE COOLER IN THIS PATTERN, HOWEVER
PRECIPITATION AMOUNTS ARE STILL VERY MUCH IN QUESTION. IF THE
CLOSED LOW SCENARIO PLAYS OUT (AROUND 30 PERCENT CHANCE) A MORE
SIGNIFICANT RAIN EVENT WOULD OCCUR ACROSS SOUTHWEST MONTANA AND
ALONG THE CONTINENTAL DIVIDE. WITH THE OPEN TROUGH SOLUTION (70
PERCENT CHANCE) MORE SHOWERY PRECIPITATION WOULD BE EXPECTED WITH
OVERALL LESS CHANCES OF A SOAKING RAIN EVENT.
AVIATION
A SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT WILL
PUSH THROUGH THE NORTHERN ROCKIES FROM THE WEST THIS AFTERNOON
AND EVENING. WELL ABOVE-NORMAL TEMPERATURES AHEAD OF THE FRONT
AND COOLER AIR BEHIND IT WILL RESULT IN INCREASED WESTERLY WINDS.
PEAK GUSTS AROUND 20–25 KNOTS ARE EXPECTED BETWEEN 29/2300Z AND
30/0300Z THIS EVENING.
THIS FRONT WILL ALSO BRING INCREASED CHANCES FOR THUNDERSTORMS,
WITH THE HIGHEST LIKELIHOOD ALONG AND EAST OF HIGHWAY 93 IN
WESTERN MONTANA. WHILE ALL TERMINALS HAVE A THREAT OF
THUNDERSTORMS, THE STRONGEST STORMS ARE ANTICIPATED ACROSS
SOUTHWEST MONTANA INCLUDING KBTM. THE MAIN THREATS INCLUDE BRIEF
HEAVY RAINFALL, LIGHTNING, AND ISOLATED GUSTY OUTFLOW WINDS UP TO
40 KNOTS. THE BEST TIMING FOR THESE IMPACTS IS CURRENTLY BETWEEN
29/2200Z AND 30/0200Z.
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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