985  
FXUS65 KTFX 291655  
AFDTFX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREAT FALLS MT  
1055 AM MDT MON MAY 29 2017  
 
UPDATED AVIATION  
   
UPDATE
 
 
LITTLE NEEDED FOR UPDATE THIS MORNING. SPC HAS CONTINUED ITS  
GENERAL RISK OF THUNDERSTORMS FROM ABOUT CUT BANK TO LEWISTOWN TO  
BILLINGS AND WESTWARD. MOST OF THE INSTABILITY IN THIS AREA WILL  
BE CONFINED TO THE MOUNTAINS...MAKING FOR A FEW ISOLATED MOUNTAIN  
THUNDERSTORMS TODAY...WITH SOME GUSTY WINDS AND SMALL HAIL. THOSE  
RECREATING AT THE HIGHER ELEVATIONS SHOULD BE ALERT FOR CHANGING  
WEATHER. THERE IS A SMALL CHANCE A THUNDERSTORM OR TWO MAY  
VENTURE AWAY FROM THE MOUNTAINS IN GLACIER COUNTY LATER THIS  
AFTERNOON INTO THE EVENING HOURS. ELSEWHERE WILL SEE A WARM AND  
MAINLY DRY DAY...WITH LIGHT WINDS COMING OUT OF THE NORTH AND  
NORTHEAST. ANGLIN  
 

 
   
SYNOPSIS
 
 
WITH AN UPPER LEVEL RIDGE OF HIGH PRESSURE RESIDING OVER THE  
REGION FOR THE NEXT FEW DAYS, EXPECT ABOVE NORMAL TEMPERATURES  
ACROSS THE REGION. WEDNESDAY LOOKS TO BE THE WARMEST DAY THIS  
WEEK, WITH AFTERNOON HIGHS IN THE MID 80S. PRECIPITATION CHANCES  
WILL BE CONFINED MOSTLY TO THE MOUNTAIN AREAS TODAY THROUGH  
WEDNESDAY.  
 

 
   
AVIATION
 
 
UPDATED 1655Z.  
 
MAINLY VFR AND QUIESCENT CONDITIONS EXPECTED NEXT 24-HOURS AS HIGH  
PRESSURE CONTINUES BUILDING-IN FROM THE WEST. THUS, NORTHWESTERLY  
FLOW ALOFT WILL PERSIST. A FEW SHOWERS AND THUNDERSTORMS MAY DEVELOP  
OVER HIGHER TERRAIN BY MID TO LATE AFTERNOON AND PERSIST THROUGH  
ABOUT 03Z/TUE. CANNOT COMPLETELY RULE OUT A SHOWER OR THUNDERSTORM  
DRIFTING OVER THE PLAINS IMMEDIATELY EAST OF THE ROCKY MOUNTAIN  
FRONT, INCLUDING KCTB.  
JASZKA  
 

 
   
PREV DISCUSSION
 
 
/ISSUED 342 AM MDT MON MAY 29 2017/  
TODAY THROUGH WEDNESDAY...WITH AN UPPER LEVEL RIDGE OVER THE  
REGION, A NICE WARMING TREND IS EXPECTED ACROSS THE ENTIRE REGION.  
AFTERNOON HIGHS WILL BE ABOVE NORMAL TODAY THROUGH WEDNESDAY, WITH  
WEDNESDAY LIKELY BEING THE WARMEST DAY THIS WEEK. I DID RAISE  
TEMPERATURES A FEW DEGREES OVER THE NATIONAL BLEND DURING THE  
AFTERNOON HOURS EACH DAY. A WEAK MID LEVEL DISTURBANCE MOVING  
SOUTHWARD ALONG THE FRONT RANGE OF THE ROCKIES THIS MORNING IS  
PRODUCING SOME LIGHT RAIN SHOWERS. MOST OF THESE SHOWERS WILL  
DIMINISH BY MID MORNING. HOWEVER, ADDITIONAL SHOWERS/ISOLATED  
THUNDERSTORMS COULD DEVELOP THIS AFTERNOON, MOSTLY OVER THE  
MOUNTAINS. A REPEAT OF MAINLY MOUNTAIN SHOWERS/THUNDERSTORMS IS  
POSSIBLE TUE/WED...MAINLY DURING THE AFTERNOON AND EVENING HOURS.  
AT THIS TIME THE MAIN THREAT FROM ANY THUNDERSTORMS THAT DO  
DEVELOP LOOKS TO BE BRIEF HEAVY RAIN AND GUSTY WINDS. BRUSDA  
 
WEDNESDAY NIGHT THROUGH MONDAY...THE UPPER LEVEL RIDGE IN PLACE AT  
THE START OF THE PERIOD IS UNLIKELY TO STICK AROUND LONG AS A BROAD  
UPPER LEVEL TROUGH BEGINS TO BE CARVED OUT FROM THE PACIFIC OCEAN  
INTO THE WESTERN US. GIVEN THE PATTERN, IT IS LIKELY THAT A MORE  
ACTIVE AND UNSETTLED PERIOD WILL ENSUE ACROSS THE AREA BEGINNING MID-  
WEEK AND POTENTIALLY CONTINUING BEYOND DAY 7.  
 
WITHIN THIS PATTERN, IT IS LIKELY THAT SEVERAL PACIFIC COLD FRONTS  
WILL TRAVERSE THE REGION, EACH BRINGING A CHANCE OF SHOWERS AND  
THUNDERSTORMS. RIGHT NOW, IT APPEARS THE GREATEST COVERAGE OF  
SHOWERS/STORMS WILL BE THURSDAY AND AGAIN LATER SUNDAY INTO MONDAY,  
ALTHOUGH THE TIMING IS LIKELY TO CHANGE SOMEWHAT, ESPECIALLY WITH  
THE FRONT OVER THE WEEKEND. WITH BOTH FRONTS, SHEAR LOOKS TO BE MORE  
THAN ADEQUATE FOR ORGANIZED CONVECTION. HOWEVER, INSTABILITY REMAINS  
THE BIGGER QUESTION MARK WHICH LEADS TO LOWER CONFIDENCE REGARDING  
THE POTENTIAL OF STRONG/SEVERE STORMS. THAT SAID, THE PATTERN  
CERTAINLY LOOKS FAVORABLE FOR A FEW STRONG TO SEVERE STORMS IF  
ENOUGH INSTABILITY CAN BE REALIZED. OF NOTE, CIPS ANALOG GUIDANCE  
SHOWS A DECENT SIGNAL FOR A FEW STRONG/SEVERE STORMS, ESPECIALLY ON  
THURSDAY. OTHERWISE, THE ONLY OTHER IMPACT OF NOTE IS THE POTENTIAL  
FOR STRONGER WIND GUSTS FRIDAY AND AGAIN ON MONDAY. FRIDAY LOOKS  
LIKE THE BEST SETUP FOR STRONGER, BUT BELOW HIGH WIND CRITERIA,  
WINDS. LATE IN THE PERIOD, THE MODELS ARE HINTING AT A BRIEF SHOT OF  
BELOW/WELL BELOW NORMAL TEMPS, BUT TOO EARLY TO GET SPECIFIC ON  
THAT. MARTIN  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
GTF 75 50 81 50 / 0 0 10 0  
CTB 74 48 79 47 / 10 20 0 0  
HLN 77 52 83 52 / 0 0 10 10  
BZN 73 45 80 45 / 0 0 10 10  
WEY 65 39 72 36 / 10 10 20 10  
DLN 74 48 79 47 / 0 0 20 10  
HVR 75 46 81 47 / 0 0 0 0  
LWT 69 45 74 47 / 0 0 0 0  
 

 
   
TFX WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
WEATHER.GOV/GREATFALLS  
 
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