669  
FXUS65 KTFX 210858  
AFDTFX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREAT FALLS MT  
258 AM MDT SUN JUL 21 2019  
   
SYNOPSIS
 
 
STRONG HIGH PRESSURE OVERHEAD WILL RESULT IN WARMING TEMPERATURES,  
PEAKING TUESDAY AND WEDNESDAY WITH TEMPERATURES IN THE UPPER-80S  
TO UPPER-90S. WHILE DRY CONDITIONS ARE EXPECTED TODAY, ISOLATED TO  
SCATTERED SHOWERS AND THUNDERSTORMS REMAIN POSSIBLE AT TIMES  
THROUGH MUCH OF THE WEEK.  
 

 
   
DISCUSSION
 
 
TODAY...  
 
AMPLIFIED HIGH PRESSURE RIDGING BUILDS INTO THE REGION TODAY.  
OUTSIDE OF SOME MORNING FOG ACROSS PARTS OF NORTH-CENTRAL MONTANA  
THIS MORNING, SKIES WILL BE MOSTLY CLEAR WITH GENERALLY LIGHT  
EASTERLY BREEZES DEVELOPING AT MOST LOCATIONS BY MID- TO LATE  
AFTERNOON.  
 
MONDAY THROUGH TUESDAY...  
 
THE AFOREMENTIONED HIGH PRESSURE RIDGE ALOFT DRIFTS EASTWARD OVER  
OUR CWA WHILE TEMPERATURES JUMP ABOUT 10 DEGREES MONDAY FROM  
SUNDAY'S HIGHS AND ANOTHER FEW DEGREES FOR TUESDAY. SUFFICIENT  
MOISTURE AND INSTABILITY WILL ALSO EXIST BY MONDAY AFTERNOON TO  
WARRANT A MENTION OF SHOWERS AND THUNDERSTORMS FOR MUCH OF THE  
REGION, ESPECIALLY WITH A DISTURBANCE APPROACHING FROM THE  
SOUTHWEST DURING THE AFTERNOON AND EARLY EVENING HOURS BOTH DAYS.  
TEMPERATURES WILL RISE AS HIGH AS THE UPPER-80S TO MID-90S ACROSS  
LOWER ELEVATIONS, WITH THE WARMEST TEMPERATURES MORE LIKELY  
TUESDAY WHERE A FEW UPPER-90S READINGS CAN NOT BE RULED OUT TOWARD  
HAVRE AND THE MILK RIVER VALLEY.  
 
WEDNESDAY THROUGH NEXT SATURDAY...A PACIFIC SHORTWAVE TROUGH SHOULD  
BREAK DOWN THE RIDGE WEDNESDAY, WITH A SIGNIFICANT COLD FRONT  
ALOFT MOVING ACROSS THE AREA, BRINGING IN ITS WAKE STRONG WESTERLY  
BREEZES AND MIXING DOWN VERY DRY AIR FROM THE MID-LEVELS OF THE  
ATMOSPHERE. WILL NEED TO WATCH FOR THE POTENTIAL FOR FIRE WEATHER  
HAZARDS. AHEAD OF THE COLD FRONT ALOFT, A FEW THUNDERSTORMS WILL  
BE POSSIBLE BUT MOST ACTIVITY LOOKS LIKE IT COULD REMAIN EAST OF  
NORTH-CENTRAL AND SOUTHWEST MT. BEHIND THIS SHORTWAVE TROUGH, HIGH  
PRESSURE RIDGING ALOFT IS PROGGED TO REBOUND OVER NORTH-CENTRAL  
AND SOUTHWEST MT THURSDAY. ISOLATED SHOWERS AND THUNDERSTORMS  
REMAIN POSSIBLE EACH DAY, ESPECIALLY DURING THE AFTERNOON/EARLY  
EVENING AND OVER/NEAR HIGHER TERRAIN. A COOLING TREND OCCURS  
DURING THIS PERIOD, BUT TEMPERATURES WILL BE NEAR TO SLIGHTLY  
ABOVE NORMAL, WITH THE WARMEST READINGS ON WEDNESDAY.  
 

 
   
AVIATION
 
 
UPDATED 1103 PM MDT SAT JUL 20 2019 (06Z TAFS)  
 
SHOWERS AND THUNDERSTORMS OVER NORTH-CENTRAL WILL GRADUALLY CLEAR  
FROM THE AREA BETWEEN 07-09Z. FOG WILL LIKELY DEVELOP BY 12Z OVER  
MANY AREAS OF NORTH-CENTRAL MT, INCLUDING KCTB AND KHVR, AND  
POSSIBLY REACH AS FAR SOUTH AS KGTF AND KLWT (THOUGH WITH VERY LOW  
CONFIDENCE). OTHERWISE, NO MAJOR AVIATION IMPACTS ARE EXPECTED AND  
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
GTF 78 52 89 60 / 0 0 0 10  
CTB 75 47 86 54 / 10 0 0 10  
HLN 83 52 91 59 / 0 0 0 20  
BZN 80 49 90 54 / 0 0 10 20  
WEY 83 42 86 47 / 0 0 10 10  
DLN 81 50 88 55 / 0 0 20 10  
HVR 80 53 89 59 / 10 0 0 10  
LWT 74 50 84 57 / 10 0 0 10  
 

 
   
TFX WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
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