948  
FXUS65 KBYZ 211622  
AFDBYZ  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE BILLINGS MT  
922 AM MST TUE NOV 21 2017  
   
UPDATE
 
 
AREAS OF FOG CONTINUE TO PERSIST ACROSS THE LIVINGSTON AREA,  
INCLUDING THE SHIELDS AND PARADISE VALLEYS. I HAVE UPDATED THE  
GRIDS TO REFLECT THIS IN THE FORECAST FOR THE REMAINDER OF THE  
MORNING. SOUTHWEST WINDS WILL PICK UP WITHIN THE NEXT FEW HOURS  
FOR LIVINGSTON WHICH WILL ALLOW THE DISSIPATION OF THE FOG. NO  
OTHER UPDATES WERE MADE TO THE FORECAST. EXPECT A PARTLY SUNNY DAY  
WITH COOLER TEMPERATURES. AFTERNOON HIGHS WILL RANGE FROM THE  
UPPER 40S FOR LIVINGSTON TO THE UPPER 20S OUT IN BAKER. HOOLEY  
 

 
   
SHORT TERM...VALID FOR TDY AND WED
 
 
THE INHERITED SHORT TERM FORECAST IS IN FAIRLY GOOD SHAPE.  
SIGNIFICANT CHANGES WERE MADE, HOWEVER TO GREATLY INCREASED WINDS  
THROUGH THE BULK OF THE PERIOD, TO SUPPORT ISSUANCE OF A WIND  
ADVISORY FOR LIVINGSTON AND NYE AREAS.  
 
THE COLD FRONT WILL RETREAT QUICKLY THIS MORNING. COLD  
TEMPS TO START THE DAY, AND SOME REMNANT CLOUD COVER WILL KEEP  
TEMPS A BIT COOLER, WITH HIGHS IN EXPECTED IN THE 40S. RIDGING  
ALOFT BUILDS IN FAIRLY QUICKLY, DRIVING TEMPS INTO THE 60S FOR  
WEDNESDAY, AND A RETURN OF MAINLY DRY CONDITIONS. SOME MOISTURE  
AND ENERGY WILL SLIDE UP THE BACK SIDE OF THE RIDGE WEDNESDAY,  
BRINGING A CHANCE OF PRECIP TO THE HIGHER ELEVATIONS.  
 
THE BIGGEST CONCERN FOR THE BULK OF THE EXTENDED PERIOD WILL BE  
GUSTY WINDS, WITH ESPECIALLY STRONG WINDS IN THE ALONG THE  
FOOTHILLS FROM LIVINGSTON TO NYE ONCE AGAIN. WINDS WILL START TO  
INCREASE THIS EVENING WITH PRESSURE GRADIENTS TIGHTENING UP TO  
SUPPORT GUSTS APPROACHING 60 MPH BY AROUND 00Z TO 03Z WEDNESDAY.  
LAG GUIDANCE SUPPORTS ADVISORY STRENGTH WINDS BY 06Z TO 09Z  
WEDNESDAY. SURFACE GRADIENTS LOOK SUPPORTIVE OF WIND GUSTS  
EXCEEDING 50 MPH THROUGH THE DAY WEDNESDAY AND INTO THE EXTENDED  
PERIOD. HAVE ISSUED WIND ADVISORY FROM 21Z TODAY THROUGH 06Z  
FRIDAY. AAG  
   
LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON
 
 
MEDIUM RANGE GUIDANCE IN OVERALL GOOD AGREEMENT. THANKSGIVING DAY  
CONTINUES TO LOOK DRY AND WINDY WITH RECORD OR NEAR RECORD HIGHS  
IN MANY AREAS AS TEMPERATURES REACH WELL INTO THE 60S. ANOTHER  
PACIFIC FRONT AND STRONG UPPER LEVEL SHORT WAVE MOVE ACROSS THE  
REGION THURSDAY NIGHT INTO FRIDAY MORNING BRINGING OUR NEXT ROUND OF  
RAIN AND SNOW SHOWERS. HAVE TRENDED PRECIPITATION CHANCES UP FOR  
THIS EVENT. HEIGHTS BEGIN TO BUILD FRIDAY INTO THE WEEKEND FOR OVERALL  
DRY CONDITIONS RETURNING. YET ANOTHER PACIFIC FRONT COULD THEN  
PUSH THROUGH NEXT MONDAY WITH MORE SHOWERS. FRIEDERS  
 

 
   
AVIATION
 
 
VLIFR TO IFR CONDITIONS IN FOG AND STRATUS AT KLVM ARE EXPECTED  
TO IMPROVE TO VFR BY 19Z. MVFR CEILINGS WILL IMPROVE OVER KSHR BY  
18Z. OTHERWISE, VFR WILL PREVAIL ACROSS THE AREA THROUGH  
WEDNESDAY MORNING. EXPECT LOCALIZED MOUNTAIN OBSCURATIONS OVER THE  
BEARTOOTHS, ABSAROKAS AND CRAZYS THIS AFTERNOON, INCREASING TO  
AREAS OF OBSCURATION THIS EVENING. OBSCURATIONS WILL CONTINUE INTO  
WED. MORNING. LOCALIZED OBSCURATIONS WILL AFFECT THE NE BIGHORNS  
WED. MORNING. SW SURFACE WINDS WILL INCREASE OVER KLVM AND NEARBY  
FOOTHILLS THIS EVENING TO 25 TO 40 KT, WITH GUSTS TO 50 KT, AND  
CONTINUE THROUGH WED. MORNING. ARTHUR  
 

 
   
PRELIMINARY POINT TEMP/POPS
 
 
TDY WED THU FRI SAT SUN MON  
-------------------------------------------------------  
BIL 044 038/063 044/065 042/055 032/050 035/056 036/052  
0/B 11/N 00/N 52/W 00/B 10/B 01/B  
LVM 048 042/059 044/061 039/050 031/049 037/055 037/048  
1/N 32/W 10/N 52/W 11/N 11/N 02/W  
HDN 043 032/063 040/067 040/056 029/051 031/058 033/054  
1/B 11/B 00/B 42/W 00/B 10/B 01/B  
MLS 032 026/060 040/065 041/054 028/049 028/053 031/050  
0/B 11/N 00/B 31/N 00/U 10/B 01/B  
4BQ 037 030/062 041/068 042/055 030/051 030/056 032/053  
0/B 01/N 00/B 32/W 00/U 00/B 00/B  
BHK 028 021/059 038/065 040/052 026/045 024/049 028/049  
0/U 11/N 00/N 31/N 00/U 10/B 01/B  
SHR 043 031/062 037/066 039/054 027/052 029/057 031/053  
1/B 01/B 00/B 23/W 00/B 00/B 01/B  
 

 
   
BYZ WATCHES/WARNINGS/ADVISORIES
 
 
MT...WIND ADVISORY IN EFFECT FROM 2 PM THIS AFTERNOON TO 11 PM MST  
THURSDAY FOR ZONES 65-66.  
WY...NONE.  
 

 
 

 
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