546  
FXUS65 KMSO 212000  
AFDMSO  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MISSOULA MT  
200 PM MDT SAT SEP 21 2019  
   
DISCUSSION
 
 
SHOWERS MOVE OUT TODAY AS A RIDGE BUILDS OVER THE NORTHERN  
ROCKIES. THIS WILL BRING CLEARING SKIES AND PLEASANT, SEASONABLE  
TEMPERATURES TONIGHT AND SUNDAY. THE RIDGE IS SHORT-LIVED, THOUGH,  
AS ANOTHER FAST-MOVING UPPER LEVEL TROUGH ARRIVES EARLY MONDAY  
MORNING. WITH THE EXITING OF THE TROUGH ON MONDAY NIGHT, PRESSURE  
GRADIENTS TIGHTEN AND A STRONG JET STREAK ALOFT NOSES ITS WAY  
INTO NORTHWEST MONTANA. MEANWHILE, PACIFIC MOISTURE IS TRANSPORTED  
OVER A LARGE, PERSISTENT CLOSED HIGH PRESSURE SYSTEM OFF OF THE  
NORTHERN CALIFORNIA COAST RESULTING IN SOME PRECIPITATION ON  
TUESDAY. MORE NOTABLY, HOWEVER, WILL BE STRONG, GUSTY WINDS ON  
TUESDAY AFTERNOON AND EVENING. WIND GUSTS COULD REACH 30 MPH IN  
THE VALLEYS AND UPWARDS OF 45 MPH IN THE HIGHER TERRAIN. BOATERS  
ON FLATHEAD LAKE SHOULD BE PREPARED FOR WINDY, CHOPPY CONDITIONS.  
 
IN THE LONGER TERM, AN UPPER LEVEL LOW DESCENDS DOWN THROUGH  
BRITISH COLUMBIA ON THURSDAY, WITH THE ASSOCIATED COLD FRONT  
CROSSING THE CANADIAN BORDER INTO MONTANA ON FRIDAY MORNING.  
TEMPERATURES DROP AND PRECIPITATION RESUMES FOR THE WEEKEND WITH  
THE FRONTAL PASSAGE. MODELS ARE AGREEING PRETTY WELL ON THIS  
FRONT. THE QUESTION AT THIS TIME IS WHAT TYPE OF PRECIPITATION  
WILL WE SEE? SNOW LEVELS OF 5000 TO 6000 FT ON FRIDAY DROP TO 3000  
TO 4000 FT BY SATURDAY MORNING AS LOW TEMPERATURES COULD EASILY  
HIT FREEZING IN THE VALLEYS. EXPECT A COLD, WET START TO OCTOBER.  
 

 
   
AVIATION
 
 
SKIES CLEAR THIS AFTERNOON AND TONIGHT AS A NICE, CLEAR DAY SHAPES  
UP FOR SUNDAY. NOT EXPECTING ANY AVIATION IMPACTS IN NEXT 24 HOURS  
SAVE SOME GUSTY WINDS AT KBTM AFTER 22/00Z. PRECIPITATION RESUMES  
ON MONDAY, AND TUESDAY WILL SEE HIGH WINDS IN THE AFTERNOON AND  
EVENING.  
 

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

 
 

 
 
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