007  
FXUS65 KMSO 281031  
AFDMSO  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MISSOULA MT  
431 AM MDT THU SEP 28 2023  
 
   
DISCUSSION
 
A COUPLE OF WEAK WEATHER DISTURBANCES WILL MOVE  
ACROSS NORTHWEST MONTANA TODAY AND FRIDAY. SCATTERED SHOWERS WILL  
OCCUR EACH DAY AND BE STRONGEST DURING THE AFTERNOON HOURS. A  
COOLER AIR MASS WILL SETTLE OVER THE REGION LOWERING SNOW LEVELS  
TO 6000-6500 FEET. SO IF ONE IS IN THE BACKCOUNTRY TODAY OR  
FRIDAY BE WARY OF SNOW SHOWERS IN THE VICINITY AS THEY WILL  
CONTAIN GUSTY WINDS WITH COOL RAW CONDITIONS.  
 
FRIDAY NIGHT INTO SATURDAY, THE ENSEMBLE MODELS HAVE TRENDED FOR  
INCOMING UPPER LEVEL TROUGH TO DIG FURTHER SOUTH TOWARDS  
CALIFORNIA AND NEVADA. BECAUSE OF THIS, THE PROBABILITY FOR SNOW  
LEVELS LESS THAN 6000 FEET HAS FALLEN SIGNIFICANTLY. THOUGH THE  
MAIN TROUGH IS OUT OF OUR REGION, THERE WILL BE A NORTHERLY BREEZE  
THAT DEVELOPS WITH HIGH PRESSURE TO THE NORTH AND LOWER PRESSURE  
TO THE SOUTH. THE SOUTHERLY FLOW ALOFT WILL BRING IN SLIGHTLY  
MILDER AND MOISTER AIR AND SET UP AN OVERRUNNING SCENARIO. THIS  
COULD BRING AREAS OF RAIN, CLOUDS AND CONTINUED COOL CONDITIONS AS  
EARLY AS FRIDAY NIGHT OVER THE NORTHERN CLEARWATER MOUNTAINS INTO  
NORTHWEST MONTANA. THEN RAIN COULD DEVELOP IN PORTIONS OF THE  
REGION LATER SATURDAY...50 PERCENT PROBABILITY OF OCCURRENCE. SNOW  
LEVELS GENERALLY WILL BE 6000 TO 7000 FEET TO THE NORTH AND UP TO  
8500 FEET TO THE SOUTH. AGAIN, BACKCOUNTRY CONDITIONS WILL  
CONTINUE TO BE RAW AND WET.  
 
ON SUNDAY THROUGH MONDAY ENSEMBLE MODELS INDICATE THAT A FEW  
LOBES OF ENERGY MAY ROTATED AROUND THE UPPER LEVEL LOW INTO OUR  
REGION, MAINLY SOUTH OF MISSOULA. SNOW LEVELS ARE PRETTY HIGH,  
GENERALLY AROUND 8000 FEET DURING THIS PERIOD.  
 
AFTER MONDAY, ZONAL FLOW IS POSSIBLE THROUGH WEDNESDAY. THAT COULD  
MEAN MILDER TEMPERATURES BUT WITH POSSIBLE SHOWERS AND CLOUD COVER  
AT TIMES.  
 
THERE IS INCREASING CONFIDENCE, AROUND 65 PERCENT PROBABILITY THAT  
A COLDER SYSTEM COULD INFLUENCE OUR WEATHER BY NEXT THURSDAY OR  
FRIDAY. TYPICALLY WITH A AMPLIFIED UPPER RIDGE OVER THE NORTHEAST  
PACIFIC INTO ALASKA, THIS COULD BRING MUCH COLDER AIR SOUTHWARDS  
OUT OF CANADA. RIGHT NOW, THE NBM FORECAST SNOW LEVELS DEPICT DOWN  
TO 5000 FEET, BUT THEY COULD BE MUCH LOWER. THE HIGHEST  
PROBABILITIES FOR GREATER THAN AN INCH OF SNOW INCLUDE MUCH OF THE  
DIVIDE NORTH OF OVANDO...AROUND 56 PERCENT FOR MARIAS PASS. ALSO  
THIS MAP TYPE WOULD SUGGEST THE POTENTIAL FOR STIFF NORTHEAST  
WINDS. IF YOU HAVE BOATS THAT COULD GET DAMAGED ON THE WESTERN  
SIDE OF FLATHEAD LAKE, YOU MIGHT WANT TO TAKE PRECAUTIONS AHEAD OF  
TIME, AND CONTINUE TO MONITOR THE FORECAST.  
 

 
   
AVIATION
 
EXPECT ISOLATED SHOWERS AT KMSO AND KGPI THIS MORNING.  
SCATTERED SHOWER ACTIVITY WILL BE LIMITED TO KGPI THIS AFTERNOON  
AND EVENING. SOME SHOWERS WILL BE STRONG ENOUGH TO PRODUCE OUTFLOW  
WINDS BRIEFLY TO 30 MPH. SHOWERS WILL DIMINISH LATER THIS EVENING  
AND OVERNIGHT AS WE LOSE THAT DAYTIME HEATING  
 

 
   
MSO WATCHES/WARNINGS/ADVISORIES
 
 
MT...NONE.  
ID...NONE.  

 
 

 
 
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