944  
FXUS65 KMSO 102001  
AFDMSO  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MISSOULA MT  
201 PM MDT FRI OCT 10 2025  
   
DISCUSSION
 
 
KEY MESSAGES:  
 
- SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THIS EVENING  
THROUGH SATURDAY.  
 
- WIDESPREAD MOUNTAIN SNOW BEGINS LATE SATURDAY NIGHT INTO SUNDAY  
MORNING, WITH HEAVIEST AMOUNTS ABOVE 4,500-5,000 FEET.  
 
- SNOW LEVELS DROP TO VALLEY FLOORS ALONG THE DIVIDE AND IN  
NORTHWEST MONTANA SUNDAY NIGHT INTO MONDAY MORNING.  
 
SOUTHWESTERLY FLOW ALOFT WILL PERSIST OVER THE NORTHERN ROCKIES  
TONIGHT ALLOWING SOME WEAK DISTURBANCES TO MOVE THROUGH THE  
REGION. THESE FEATURES WILL KICK OFF A FEW LIGHT SHOWERS AND  
POTENTIAL THUNDERSTORMS. THE FIRST COUPLE ROUNDS OF SHOWERS COULD  
CREATE GUSTY OUTFLOW WINDS.  
 
A TROUGH OF LOW PRESSURE WILL MOVE ACROSS THE NORTHERN ROCKIES ON  
SATURDAY. THIS TROUGH WILL BRING SIGNIFICANTLY COOLER AIR AND  
SCATTERED RAIN SHOWERS. THE HEAVIEST PRECIPITATION APPEARS TO BE  
DRAPED ACROSS LEMHI COUNTY INTO SOUTHWEST MONTANA.  
 
AN ARCTIC AIRMASS IS ANTICIPATED TO DROP SOUTHWARD OUT OF CENTRAL  
CANADA SATURDAY NIGHT CAUSING UPSLOPE FLOW ALONG THE CONTINENTAL  
DIVIDE. THIS FLOW PATTERN WILL ENHANCE THE PRECIPITATION AROUND  
GLACIER NATIONAL PARK INTO THE BOB MARSHALL WILDERNESS. SNOW  
LEVELS WILL BE DRAMATICALLY DROP TO AROUND 3000 FEET BY SUNDAY  
MORNING AROUND THE PARK. THE AREA WILL RECEIVE SEVERAL INCHES OF  
NEW SNOW BY SUNDAY MORNING WITH A HIGH POTENTIAL FOR WET ROADS  
EXPERIENCING A FLASH FREEZE DURING THE OVERNIGHT HOURS AS  
TEMPERATURES DRASTICALLY DROP.  
 
A SECONDARY LOW PRESSURE SYSTEM DIGS INTO WASHINGTON ON SUNDAY  
CAUSING A STREAM OF PRECIPITATION OVER THE NORTHERN ROCKIES  
ESPECIALLY NORTHWEST MONTANA. SUNDAY NIGHT AS THE LOW DIGS  
SOUTHWARD INTO OREGON, THE ARCTIC AIR WILL BE PULLED FURTHER INTO  
WESTERN MONTANA CAUSING GUSTY EASTERLY WINDS. THE COMBINATION OF  
EASTERLY WINDS AT THE SURFACE ALONG WITH MOISTURE STREAM INTO FROM  
THE WEST DUE TO LOW PRESSURE SYSTEM WILL CREATE AN OVERRIDING SNOW  
EVENT WITH EXTREME NORTHWEST MONTANA HAVE THE BEST POTENTIAL FOR  
HIGH IMPACTS. THE VALLEYS OF NORTHWEST MONTANA COULD EXPERIENCE 1  
TO 4 INCHES OF SNOW SUNDAY NIGHT INTO MONDAY MORNING WHILE THE  
HIGHER TERRAIN COULD RECEIVE UP TO A FOOT OR TWO OF SNOW. THE  
HEAVY WET SNOW THIS TIME OF YEAR COULD CREATE BROKEN TREE BRANCHES  
AND POWER OUTAGES DUE TO THE EXTENT OF LEAVES THAT REMAIN ON THE  
TREES.  
 
THE LOW PRESSURE SYSTEM DIGS DOWN INTO CALIFORNIA MONDAY INTO  
TUESDAY. THE PLACEMENT OF THIS SYSTEM WILL LIMIT THE SHOWER  
ACTIVITY OVER THE NORTHERN ROCKIES, BUT THE COLD AIR WILL REMAIN  
IN PLACE. CLEARING SKIES AND RELAXING WINDS SHOULD ALLOW  
TEMPERATURES TO DROP DRAMATICALLY MONDAY NIGHT INTO TUESDAY  
MORNING. MOST VALLEYS OF NORTHERN ROCKIES SHOULD HAVE TUESDAY  
MORNING TEMPERATURES READINGS IN THE TEENS TO MID 20S WHILE THE  
LOW VALLEYS OF NORTH CENTRAL IDAHO BEING IN THE 30S TO LOW 40  
DEGREES.  
 

 
   
AVIATION
 
WIDESPREAD VFR WEATHER CONDITIONS TODAY WILL BEGIN TO  
DETERIORATE THIS AFTERNOON WITH THE ONSET OF SHOWERS AND ISOLATED  
THUNDERSTORMS WHICH COULD CREATE BRIEF GUSTY OUTFLOW UP TO 30  
KNOTS MAINLY AFTER 10/2200Z. THE STRONGEST WINDS AND GREATEST  
THREAT FOR THUNDERSTORMS WILL BE NEAR KBTM WITH SURFACE GUSTS  
ABOVE 20 KNOTS ARE EXPECTED INTO THE EVENING. SUSTAINED SOUTHERLY  
RIDGETOP WINDS WILL REMAIN IN THE 15-20 KNOT RANGE, BECOMING  
INCREASINGLY SOUTHWESTERLY INTO TOMORROW. THERE IS POTENTIAL FOR  
LOWERED CEILINGS AND VALLEY FOG ESPECIALLY NEAR KGPI, KMSO, BY  
SATURDAY MORNING AFTER 11/1200Z. SCATTERED SHOWER CHANCES CONTINUE  
FOR MOST AREAS THROUGH THE DAY ON SATURDAY WITH SNOW/FREEZING  
LEVELS LOWERING THROUGH 6,000 FT MSL.  
 

 
   
MSO WATCHES/WARNINGS/ADVISORIES
 
 
MT...WINTER WEATHER ADVISORY FROM 6 PM SATURDAY TO NOON MDT MONDAY  
FOR BITTERROOT/SAPPHIRE MOUNTAINS...BUTTE/BLACKFOOT  
REGION...LOWER CLARK FORK REGION...POTOMAC/SEELEY LAKE  
REGION.  
 
WINTER STORM WATCH FROM SATURDAY EVENING THROUGH MONDAY MORNING  
FOR KOOTENAI/CABINET REGION.  
 
WINTER STORM WARNING FROM 6 PM SATURDAY TO NOON MDT MONDAY FOR  
WEST GLACIER REGION.  
 
ID...WINTER WEATHER ADVISORY FROM 5 PM SATURDAY TO 11 AM PDT MONDAY  
FOR NORTHERN CLEARWATER MOUNTAINS...SOUTHERN CLEARWATER  
MOUNTAINS.  
 
WINTER WEATHER ADVISORY FROM 6 PM SATURDAY TO 6 AM MDT MONDAY  
FOR EASTERN LEMHI COUNTY...WESTERN LEMHI COUNTY.  
 

 
 

 
 
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