848  
FXUS65 KMSO 121011  
AFDMSO  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MISSOULA MT  
411 AM MDT FRI SEP 12 2025  
   
DISCUSSION  
 
KEY MESSAGES:  
 
- AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ARE EXPECTED  
TODAY, ESPECIALLY FOCUSED OVER THE MOUNTAINS IN NORTHWEST  
MONTANA. THREATS INCLUDE GUSTY OUTFLOW WINDS UP TO 45 MPH,  
LOCALIZED HEAVY DOWNPOURS, SMALL HAIL, AND FREQUENT LIGHTNING.  
 
- SEASONABLE TEMPERATURES THIS WEEKEND WITH A FAIR AMOUNT OF  
SUNSHINE THROUGH SUNDAY MORNING.  
 
- INCREASING CLOUDS AND A CHANCE FOR SHOWERS ON SUNDAY INTO  
MONDAY AS ANOTHER WEATHER SYSTEM MOVES THROUGH THE REGION.  
 
ANOTHER ROUND OF SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED  
THIS AFTERNOON AND EVENING. MODEL GUIDANCE CONTINUES TO SHOW THE  
HEAVIER SHOWERS ACROSS THE HIGHER TERRAIN OF NORTHWEST MONTANA  
INCLUDING THE BOB MARSHALL WILDERNESS, GLACIER NATIONAL PARK,  
SALISH MOUNTAINS AND CABINET RANGE. THIS COULD BRING PERIODS OF  
HEAVY RAIN TO THE GOING TO THE SUN ROAD. THREATS OF GUSTY WINDS  
AND LIGHTNING WILL PERSIST. STORMS WILL BE MORE SCATTERED  
ELSEWHERE OVER THE BITTERROOT MOUNTAINS. BY TONIGHT AND INTO  
SATURDAY MORNING, PARTIAL CLEARING COMBINED WITH MOIST GROUND  
COULD LEAD TO PATCHY VALLEY FOG.  
 
BY SATURDAY, THE UPPER LOW FINALLY SHIFTS INTO EASTERN MONTANA.  
OUR REGION WILL REMAIN UNDER CYCLONIC FLOW, SUPPORTING SCATTERED  
SHOWERS AND A FEW ISOLATED THUNDERSTORMS, PRIMARILY ACROSS WESTERN  
MONTANA. SUNDAY MAY OFFER A BRIEF LULL WITH SOME MORNING SUN  
BEFORE CLOUDS INCREASE AHEAD OF OUR NEXT APPROACHING WEATHER  
SYSTEM.  
 
CONFIDENCE IS INCREASING ON ANOTHER PACIFIC TROUGH WILL MOVE INTO  
THE REGION SUNDAY AFTERNOON INTO MONDAY, USHERING IN ANOTHER  
ROUND OF WIDESPREAD SHOWERS AND COOLER TEMPERATURES, AND INCREASED  
WESTERLY WINDS.  
 
WHAT HAS CHANGED IN THE ENSEMBLES? THERE SEEMS TO BE MORE CLUSTERS  
THAT SUPPORT A MORE DIGGING TROUGH, WHERE THE BASE OF IT IS MORE  
OVER SOUTHERN IDAHO ON MONDAY. THIS WOULD FAVOR MORE WIDESPREAD  
SHOWERS ACROSS NORTH-CENTRAL IDAHO INTO SOUTHWEST MONTANA, BUT  
LESS AMOUNTS ACROSS NORTHWEST MONTANA.  
 
WE WILL CONTINUE TO MONITOR THIS SYSTEM CLOSELY AS IT DEVELOPS.  
FOR NOW, PLAN ON A COOL AND WET START TO THE WORK WEEK.  
THEREAFTER, TUESDAY AND WEDNESDAY WILL BE VERY PLEASANT DAYS WITH  
SEASONABLE TEMPERATURES. ENSEMBLES DEPICT A POSSIBLE RIDGE-  
BREAKDOWN NEXT THURSDAY WHICH COULD BRING BREEZY WINDS TO THE  
AREA.  
 
 
   
AVIATION  
SHOWERS AND THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON  
AND EVENING, ESPECIALLY OVER THE MOUNTAINOUS TERRAIN OF WESTERN  
MONTANA AND NORTH-CENTRAL IDAHO. THREATS INCLUDE ERRATIC WIND  
GUSTS TO 40 KNOTS, HEAVY RAIN, SMALL HAIL AND LIGHTNING. SHOWER  
ACTIVITY IS EXPECTED TO WANE BY 13/0600Z. PATCHY VALLEY FOG ALONG  
WITH LINGERING LOWERED CEILINGS/STRATUS ARE POSSIBLE THROUGH  
ABOUT 13/1400Z SATURDAY MORNING.  
 
 
   
MSO WATCHES/WARNINGS/ADVISORIES  
 
MT...NONE.  
ID...NONE.  
 
 
 
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