998  
FXUS65 KBYZ 191206  
AFDBYZ  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE BILLINGS MT  
506 AM MST THU DEC 19 2024  
   
KEY MESSAGES
 
 
- GUSTY NW WINDS WILL GRADUALLY DIMINISH OVER THE AREA TODAY.  
 
- ABOVE NORMAL TEMPERATURES. OCCASIONAL CHANCES OF LIGHT  
PRECIPITATION THROUGH THE MIDDLE OF NEXT WEEK. ALMOST DAILY  
CHANCES FOR WINDS OVER 50MPH IN WESTERN FOOTHILLS STARTING  
SUNDAY.  
 

 
   
UPDATE
 
 
WINDS ARE CONTINUING TO GRADUALLY DECREASE OVER THE AREA THIS  
MORNING, WITH GUSTS NOW INTO THE 40S MPH OVER THE FAR EAST. AS  
SUCH, HAVE ALLOWED THE HIGH WIND WARNING FOR THE EAST TO EXPIRE.  
STP  
 

 
   
DISCUSSION
 
 
TODAY THROUGH FRIDAY NIGHT...  
 
A STRONG AND COMPACT WAVE WAS SLIDING EAST INTO NORTH DAKOTA  
EARLY THIS MORNING, WITH AN ASSOCIATED COLD FRONT CONTINUING TO  
DROP THROUGH THE AREA. EASTERN AREAS HAD WARMED INTO THE UPPER 30S  
TO 40S AHEAD OF THE FRONT, BUT HAVE NOW DROPPED INTO THE 20S  
BEHIND THE FRONT. STRONG WESTERLY WINDS HAVE BEEN GRADUALLY  
DECREASING OVER WESTERN AND CENTRAL AREAS, WHILE EASTERN AREAS CAN  
EXPECT STRONG NW WINDS TO CONTINUE A WHILE LONGER, GUSTING INTO  
THE 50-60 MPH RANGE. HAVE GONE AHEAD AND EXPIRED THE HIGH WIND  
WARNINGS OVER PORTIONS OF THE WEST AND CENTRAL ZONES, AND  
CANCELLED THE WIND ADVISORY FOR THE LIVINGSTON AREA AND BEARTOOTH  
FOOTHILLS, WITH WINDS DECREASING THERE. THE HIGH WIND WARNING FOR  
CUSTER, FALLON, POWDER RIVER AND CARTER COUNTIES EXPIRES AT 5AM.  
 
MAINLY DRY CONDITIONS CAN BE EXPECTED ACROSS THE AREA TODAY, WITH  
NW WINDS GRADUALLY DIMINISHING OVER THE EAST. HIGH PRESSURE  
BUILDING IN FROM THE WEST WILL KEEP WESTERN AND CENTRAL AREAS WARM  
WITH HIGHS IN THE 40S, WHILE EASTERN AREAS WILL BE COOL, WITH  
HIGHS IN THE MIDDLE TEENS TO 20S, COLDEST NEAR BAKER. A SHORTWAVE  
MOVING ACROSS THE MT/CANADA BORDER TONIGHT WILL CAUSE PRESSURE  
GRADIENTS TO TIGHTEN ALONG THE WESTERN FOOTHILLS, WITH INCREASING  
WINDS ALOFT. SW WINDS WILL INCREASE IN THE LIVINGSTON FACILITY,  
BUT ARE EXPECTED TO REMAIN BELOW 50 MPH AT THIS TIME (LESS THAN  
50% CHANCE). THE WEAK WAVE WILL DROP SOUTHEAST THROUGH NE MT INTO  
THE DAKOTAS ON FRIDAY, KEEPING THE EAST ON THE COOL SIDE, BUT  
WITH LITTLE IMPACT TO THE REST OF THE AREA BESIDES INCREASE  
BREEZINESS. HIGH TEMPERATURES WILL RANGE FROM THE 40S AND 50S OVER  
WESTERN AND CENTRAL AREAS, TO THE LOWER 30S OVER THE FAR EAST. STP  
 
SATURDAY THROUGH THURSDAY...  
 
THE LONG TERM WILL SEE PERSISTENT ABOVE AVERAGE 500MB HEIGHTS  
WITH OCCASIONAL SHORTWAVE TROUGHS MOVING THROUGH. THIS WILL LEAD  
TO WARM TEMPERATURES IN THE 40S TO LOW 50S AND GENERALLY DRY  
CONDITIONS.  
 
THE FIRST WAVE WILL MOVE IN SUNDAY BRINGING LOW (30%)  
PRECIPITATION CHANCES. DUE TO THE WARM TEMPERATURES, SNOW WOULD  
LIKELY BE LIMITED TO THE HIGH TERRAIN WITH RAIN TO MIXED  
PRECIPITATION FOR THE LOWER ELEVATIONS. WPC CLUSTERS ARE IN GOOD  
AGREEMENT IN KEEPING ANY PRECIPITATION FROM THIS LIGHT, WITH ALL  
CLUSTERS SHOWING LESS THAN 0.06 INCHES.  
 
A MORE SIGNIFICANT TROUGH IS POSSIBLE THE MIDDLE OF NEXT WEEK.  
THIS IS SEEN IN THE DETERMINISTIC MODELS AS WELL AS ABOUT 40% OF  
THE WPC CLUSTERS. NOT MUCH IS KNOWN ABOUT THIS SYSTEM BUT NBM IS  
CURRENTLY GIVING A 10-30% CHANCE FOR GREATER THAN 0.1 INCHES OF  
PRECIPITATION. TEMPERATURES WOULD LIKELY KEEP THIS AS MOSTLY RAIN  
FOR THE LOWER ELEVATIONS BUT CANT SAY MUCH AT THIS POINT. WILL  
HAVE TO KEEP AN EYE ON THIS DUE TO THE POSSIBILITY OF INCREASED  
IMPACTS FOR CHRISTMAS TRAVEL.  
 
STARTING SUNDAY, STRONG WIND WILL BE AN ALMOST DAILY OCCURRENCE  
FOR THE WESTERN FOOTHILLS. PERSISTENT WESTERLY 700MB WINDS WILL  
CREATE LEE SIDE TROUGHING. THIS WILL HELP CREATE A PERSISTENT  
STRONG IDAHO FALLS TO LEWISTOWN PRESSURE GRADIENT WITH THE  
DETERMINISTIC GFS CURRENTLY SHOWING THE GRADIENT REMAINING ABOVE  
10MB THROUGH THE WEEK. 700MB WINDS MAY NOT ALWAYS BE FAVORABLE  
HOWEVER WHICH MAY BRING SOME BREAKS. TORGERSON  
 

 
   
AVIATION
 
 
STRONG WINDS WILL CONTINUE TO DECREASE TONIGHT THROUGH THE  
MORNING. WINDS WILL DECREASE FROM EAST TO WEST WITH WINDS  
CONTINUING TO GUST AROUND 30KTS NEAR THE DAKOTAS BORDER THROUGH  
THE MORNING. THIS AFTERNOON WILL SEE CLEAR SKIES, DRY CONDITIONS,  
AND LIGHT WINDS. CLOUDS WILL BEGIN TO MOVE INTO THE REGION FROM  
WEST TO EAST AROUND 00Z FRIDAY. TORGERSON  
 

 
   
PRELIMINARY POINT TEMP/POPS
 
 
TDY FRI SAT SUN MON TUE WED  
-------------------------------------------------------  
BIL 042 025/052 032/053 037/051 029/049 029/049 033/046  
0/U 00/B 00/B 22/W 01/B 01/B 32/W  
LVM 047 032/054 033/054 035/047 029/047 030/051 030/044  
0/N 00/N 00/B 41/N 02/W 02/W 52/W  
HDN 038 020/049 025/051 030/050 024/049 026/049 029/046  
1/U 00/B 00/B 23/W 01/B 00/B 33/W  
MLS 021 011/038 020/043 025/043 024/044 025/044 027/042  
1/M 00/B 00/B 13/W 00/U 00/U 22/W  
4BQ 032 017/044 026/050 029/046 026/046 028/049 030/044  
1/M 00/B 00/U 12/W 00/U 00/U 22/W  
BHK 015 002/030 016/043 022/040 021/041 022/043 023/039  
1/M 00/E 00/B 02/W 00/U 00/U 11/E  
SHR 042 021/054 027/056 030/050 024/049 025/052 027/046  
0/U 00/B 00/U 12/W 01/B 00/B 33/W  
 

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

 
 

 
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