463  
FXUS65 KBYZ 211519  
AFDBYZ  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE BILLINGS MT  
919 AM MDT MON AUG 21 2017  
   
UPDATE
 
 
FORECAST LOOKS ON TRACK THIS MORNING. SOME PATCHY MID AND HIGH  
LEVEL CLOUDS STILL CLINGING TO THE MT/WY BORDER WILL CONTINUE TO  
DRIFT SOUTHWARD AND DIMINISH IN COVERAGE BY AFTERNOON. PATCHY  
SMOKE CONTINUES TO HANG AROUND THE AREA THIS MORNING WITH DENSER  
SMOKE OVER WESTERN ZONES. STILL EXPECTING HIGHS IN THE 80S WITH NO  
RAIN CHANCES THIS AFTERNOON. WALSH  
 

 
   
SHORT TERM...VALID FOR TDY AND TUE
 
 
QUIET WEATHER PATTERN FOR THE NEXT COUPLE OF DAYS. THE UPPER  
LEVEL DISTURBANCE AND LOW-LEVEL JET THAT BROUGHT THE SHOWER AND  
AND THUNDERSTORM ACTIVITY TO SOUTHERN CARTER COUNTY LAST EVENING  
AND EARLY THIS MORNING HAS MOVED EAST OF THE AREA TAKING THE  
THUNDERSTORM ACTIVITY INTO SOUTH DAKOTA. CURRENTLY SOME MID AND  
HIGH LEVEL CLOUDS ARE MOVING ACROSS OUR CENTRAL ZONES AND THESE  
SHOULD SLOWLY SHIFT SOUTHEAST DURING THE COURSE OF THIS MORNING  
LEAVING A PARTLY TO MOSTLY SUNNY DAY IN STORE ACROSS THE FORECAST  
AREA. THERE WILL STILL BE SOME AREAS OF SMOKE AROUND THIS MORNING  
BUT WINDS ARE EXPECTED TO SHIFT TO THE NORTH AND NORTHEAST BY  
AFTERNOON AND THIS SHOULD HELP TO SHIFT ANY SMOKE BACK WEST AND  
SOUTH OUT OF MOST OF OUR FORECAST AREA.  
 
HIGH PRESSURE RIDGING WILL BUILD ACROSS THE FORECAST AREA TODAY  
INTO TUESDAY. THIS WILL RESULT IN DRY CONDITIONS AND SLIGHTLY  
WARMER TEMPERATURES. AFTERNOON HIGHS TODAY WILL BE IN THE LOWER  
80S, WITH UPPER 80S TO AROUND 90 DEGREES EXPECTED FOR MOST AREAS  
ON TUESDAY. HOOLEY  
   
LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN
 
 
SOME ENSEMBLE UNCERTAINTY/MODEL SPREAD BEGINS TO SHOW UP DURING  
THE THURSDAY INTO FRIDAY PERIOD OF THE EXTENDED WHICH LOOKS LIKE  
THE MOST ACTIVE PART OF THE PERIOD. WEDNESDAY WILL BE VERY WARM  
AND DRY WITH LIGHT WINDS UNDER A HIGH PRESSURE RIDGE. AN UPPER  
LOW/TROUGH WILL MOVE THROUGH WESTERN CANADA WED. NIGHT THROUGH  
THURSDAY BRINGING SW FLOW TO THE AREA, WITH A LOW-LEVEL JET OVER  
THE E. CHANCES FOR THUNDERSTORMS WILL INCREASE OVER MUCH OF THE  
AREA THU. AFTERNOON. A COLD FRONT PUSHES THROUGH MUCH OF THE  
REGION THU. NIGHT, WITH ACCOMPANYING SHOWERS AND THUNDERSTORMS. IT  
WILL BE SLIGHTLY COOLER ON THU. WITH INCREASED CLOUD  
COVER/PRECIPITATION. MODELS DIFFERED ON THE POSITION OF THE  
CANADIAN UPPER LOW ON FRIDAY, WITH THE GFS POSITIONING IT FURTHER  
N THAN THE ECMWF. EITHER SOLUTION BRINGS A CHANCE OF THUNDERSTORMS  
TO THE MOUNTAINS AND FAR E. GFS SHOWED HIGH ML CAPES OVER THE E,  
WITH GOOD BRN VALUES, FOR POSSIBLE STRONG STORMS FRI. AFTERNOON  
AND EVENING. THIS IS SOMETHING THAT WILL NEED TO BE WATCHED. ZONAL  
FLOW THEN GIVES WAY TO UPPER RIDGING FOR THE REMAINDER OF THE  
PERIOD WITH DRY WEATHER AND NEAR NORMAL TEMPERATURES. ARTHUR  
 

 
   
AVIATION
 
 
VFR WILL PREVAIL OVER THE AREA TODAY AND TONIGHT. AREAS OF SMOKE  
COULD CREATE SLANTWISE VISIBILITY ISSUES TODAY. ARTHUR  

 
   
PRELIMINARY POINT TEMP/POPS
 
 
TDY TUE WED THU FRI SAT SUN  
-------------------------------------------------------  
BIL 084 056/089 059/092 062/089 060/083 056/085 056/086  
0/K 00/U 00/U 02/T 21/B 10/U 00/U  
LVM 084 047/091 050/092 053/087 051/083 047/086 047/087  
0/K 00/U 01/U 13/T 32/T 20/U 00/U  
HDN 086 053/092 055/095 060/092 059/086 055/087 054/088  
0/K 00/U 00/U 02/T 21/B 10/U 00/U  
MLS 084 054/089 058/093 062/092 063/087 056/086 056/087  
0/B 00/U 00/U 01/B 21/B 10/U 00/U  
4BQ 084 052/089 056/092 059/090 060/087 055/087 055/087  
0/B 00/U 00/U 12/T 22/T 21/U 00/U  
BHK 082 049/085 053/088 055/087 059/085 053/083 052/084  
1/B 00/U 00/U 01/B 23/T 20/U 10/U  
SHR 083 050/089 053/091 056/089 055/084 051/084 050/086  
0/K 00/U 01/U 12/T 23/T 30/U 00/U  
 

 
   
BYZ WATCHES/WARNINGS/ADVISORIES
 
 
MT...NONE.  
WY...NONE.  
 

 
 

 
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