199
FXUS65 KMSO 290941
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
341 AM MDT FRI AUG 29 2025
DISCUSSION
KEY MESSAGES:
- LOCALLY DENSE FOG MAY REDUCE VISIBILITY THIS MORNING, ESPECIALLY
ALONG AND SOUTH OF INTERSTATE 90 AND IN THE VALLEYS OF NORTH-
CENTRAL IDAHO
- THUNDERSTORMS CAPABLE OF HEAVY RAINFALL THIS AFTERNOON IN
NORTHWEST MONTANA
- WARMING AND DRYING TREND THIS WEEKEND
LINGERING LOW-LEVEL MOISTURE WILL SUPPORT DENSE VALLEY FOG FORMATION BY
MORNING WHERE SKIES HAVE CLEARED OVERNIGHT, GENERALLY ALONG AND
SOUTH OF THE I90 CORRIDOR.
THE EXITING TROUGH WILL FOCUS SHOWER AND THUNDERSTORM ACTIVITY
OVER NORTHWEST MONTANA THIS AFTERNOON. WEAK STEERING FLOW WILL
PROMOTE SLOW-MOVING STORMS CAPABLE OF HEAVY RAINFALL, WITH RATES
POTENTIALLY EXCEEDING 0.75 INCHES PER HOUR. THIS COULD LEAD TO
LOCALIZED RUNOFF ISSUES, PARTICULARLY IN STEEP TERRAIN AND FLOOD
PRONE BASINS. MODEL GUIDANCE INDICATES A 20-30% PROBABILITY OF
SUCH RATES OCCURRING IN GLACIER NATIONAL PARK.
A SIGNIFICANT PATTERN CHANGE ARRIVES THIS WEEKEND AS AN UPPER-
LEVEL RIDGE BUILDS OVER THE REGION. THIS WILL BRING AN END TO
PRECIPITATION AND INITIATE A PRONOUNCED WARMING TREND. DRY AND
PROGRESSIVELY WARMER CONDITIONS ARE EXPECTED THROUGH THE WEEKEND
AND MUCH OF NEXT WEEK, WITH HIGH TEMPERATURES CLIMBING
10-15F ABOVE SEASONAL NORMALS.
AVIATION
LOW LEVEL MOISTURE FROM RAIN SHOWERS ON THURSDAY HAS
ALLOWED FOR A MIX OF STRATUS AND VALLEY FOG TO DEVELOP THIS
MORNING FOR MANY AREAS IN WESTERN MONTANA AND NORTH CENTRAL IDAHO.
LOCALLY DENSE FOG CURRENTLY EXISTS ALONG PORTIONS OF THE I90
CORRIDOR INCLUDING AT KBTM AND PERIODICALLY AT KMSO. ANTICIPATED
LOCALLY LOWERED VISIBILITY AND CEILING THROUGH ROUGHLY 29/1500Z.
CHANCES FOR AFTERNOON SHOWERS AND THUNDERSTORMS WILL EXIST
PRIMARILY IN NORTHWEST MONTANA, WITH KGPI HAVING THE BEST CHANCE
(30-40 PERCENT). THE SLOW MOVING NATURE OF STORMS WILL MAKE HEAVY
RAIN AND LIGHTNING THE MAIN THREATS WITH ANY STORMS THAT DEVELOP.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page