868  
FXUS65 KTFX 141112  
AFDTFX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREAT FALLS MT  
520 AM MDT FRI MAY 14 2021  
   
..UPDATED AVIATION SECTION
 
 
   
SYNOPSIS
 
 
 
AN ACTIVE WEATHER PATTERN WILL KEEP SPOTTY SHOWER AND  
THUNDERSTORM CHANCES ACROSS THE REGION TODAY. SHOWERS AND  
THUNDERSTORM ACTIVITY THEN BECOMES MORE PROGRESSIVELY CONFINED TO  
SOUTHWESTERN AND CENTRAL MONTANA THROUGH THE WEEKEND AS HIGH  
PRESSURE ALOFT MOVES TOWARD THE REGION. DAYTIME HIGH TEMPERATURES  
WILL GENERALLY TREND WARMER EACH DAY THROUGH MONDAY.  
 

 
   
DISCUSSION
 
 
TODAY THROUGH SATURDAY...  
 
MULTIPLE DISTURBANCES WILL CONTINUE TO MOVE WEST TO EAST ACROSS  
THE REGION TODAY AND TONIGHT, AND FINALLY CLEAR THE REGION FROM  
NORTHWEST TO SOUTHEAST SATURDAY NIGHT. FOR TODAY, WIDESPREAD  
SUFFICIENT MOISTURE, SYNOPTIC-SCALE LIFT, AND LOW STABILITY WILL  
RESULT IN A REGION-WIDE CHANCE FOR SPOTTY SHOWERS AND  
THUNDERSTORMS. HIGH TEMPERATURES IN THE 60S WILL BE SIMILAR TO  
THURSDAY GIVEN SIMILAR WIDESPREAD SPOTTY SHOWERS AND  
THUNDERSTORMS. THE MAIN UPPER DISTURBANCE CROSSES THE REGION  
SATURDAY, BRINGING DRIER AIR TO NORTH-CENTRAL MONTANA AND REDUCING  
THE SHOWER THREAT THERE, WHILE CENTRAL AND SOUTHWEST MONTANA  
MAINTAINS SHOWER AND THUNDERSTORM CHANCES AT LEAST UNTIL THE UPPER  
TROUGH MOVES OUT OF THE AREA BY SATURDAY EVENING OR OVERNIGHT,  
REPLACED BY UPPER RIDGING MOVING INTO THE REGION FROM THE WEST.  
 
SUNDAY THROUGH NEXT THURSDAY...  
 
UPPER LEVEL RIDGING STRENGTHENS ACROSS THE NW US AND NORTHERN  
ROCKIES SUNDAY AND MONDAY FOR MAINLY DRY CONDITIONS AND  
TEMPERATURES WARMING ABOVE SEASONAL AVERAGES. MEDIUM-RANGE  
DETERMINISTIC AND ENSEMBLE GUIDANCE CONTINUES TO TREND TOWARD  
STRONGER AND LONGER DURATION RIDGING OVER THE REGION THAT NOW  
LOOKS TO CONTINUE THROUGH AT LEAST TUESDAY OF NEXT WEEK. THIS  
WOULD RESULT IN AFTERNOON TEMPERATURES NEAR OR EXCEEDING 80F FOR  
MANY LOWER ELEVATION SITES SUNDAY THROUGH TUESDAY ALONG WITH  
MINIMAL CHANCES FOR PRECIPITATION. THE RIDGE LOOKS TO SHIFT EAST  
BY THE MIDDLE OF NEXT WEEK WITH SW FLOW INCREASING ACROSS THE  
REGION TUESDAY AND WEDNESDAY AS THE NEXT PACIFIC TROUGH MOVES  
ONSHORE BRINGING BETTER CHANCES FOR PRECIPITATION AND SOME COOLING  
BY MID-LATE NEXT WEEK.  
 

 
   
AVIATION
 
 
530 AM MDT FRI MAY 14 2021 (14/12Z TAF PERIOD)  
 
MAINLY VFR CONDITIONS ARE EXPECTED OVER THE UPCOMING TAF PERIOD AT  
ALL AREA TERMINALS. BIGGEST CONCERN TODAY WILL BE THE DEVELOPMENT OF  
SHOWERS AND THUNDERSTORMS ACROSS SW MT, SOME OF WHICH MAY PRODUCE  
LOCALIZED MVFR CONDITIONS AND GUSTY WINDS. ACROSS THE PLAINS,  
SHOWERS AND STORMS SHOULD BE MUCH LESS WIDESPREAD. LUDWIG  
 
REFER TO WEATHER.GOV/ZLC FOR MORE DETAILED REGIONAL AVIATION WEATHER  
AND HAZARD INFORMATION.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
GTF 67 40 72 43 / 20 10 10 0  
CTB 65 39 71 43 / 20 20 10 0  
HLN 70 44 74 45 / 30 20 10 0  
BZN 69 40 70 39 / 30 20 20 0  
WYS 64 31 63 28 / 40 30 30 0  
DLN 67 40 69 39 / 20 20 10 0  
HVR 69 43 74 46 / 20 0 10 0  
LWT 64 39 68 41 / 30 20 20 0  
 

 
   
TFX WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
HTTP://WWW.WEATHER.GOV/GREATFALLS  
 
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