866  
FXUS65 KBYZ 202018  
AFDBYZ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BILLINGS MT  
118 PM MST FRI DEC 20 2024  
   
KEY MESSAGES
 
 
- GUSTY SW-W WINDS CONTINUE ALONG THE WESTERN FOOTHILLS THROUGH  
THE WEEKEND.  
 
- ABOVE NORMAL TEMPERATURES CONTINUE NEXT WEEK, WITH PERIODIC  
WINDY CONDITIONS ALONG THE FOOTHILLS.  
 
- TRAVEL CONDITIONS LOOK GOOD LEADING UP TO CHRISTMAS.  
 

 
   
DISCUSSION
 
 
THROUGH SATURDAY NIGHT...  
 
WARM WEATHER WITH PERIODIC WINDY CONDITIONS ALONG THE FOOTHILLS  
IS THE THEME MOVING AHEAD. SATELLITE IMAGERY SHOWS A WEAK  
SHORTWAVE CLIPPING NORTHEAST MT MOVING INTO ND, WITH DRY AIR IN  
ITS WAKE OVER OUR REGION. WITHOUT ANY REAL COLD ADVECTION BEHIND  
THIS WAVE, THE INCREASED MIXING AND SUNNY CONDITIONS ARE PUSHING  
TEMPS UP RAPIDLY AT MIDDAY. TEMPS HAVE ALREADY REACHED THE UPPER  
50S FROM LIVINGSTON (TODAY'S DAILY RECORD HAS BEEN BROKEN) TO  
HARLOWTON, AND THE LOWER 50S AT ROUNDUP AND BILLINGS. TEMPS WILL  
REMAIN BELOW FREEZING NEAR THE DAKOTAS BORDER, EAST OF WHERE THE  
DOWNSLOPE FLOW IS REACHING.  
 
BUILDING UPPER RIDGE WILL KEEP THINGS DRY AND WARM THROUGH  
SATURDAY. IN FACT, TOMORROW LOOKS A LITTLE WARMER THAN TODAY,  
THOUGH CLOUD COVER COULD HAVE A LIMITING EFFECT (SOME UNCERTAINTY  
HERE, BUT THE CHANCES OF REACHING 60F ARE NON-ZERO WEST OF ROSEBUD  
COUNTY). WINDS WILL REMAIN ELEVATED ALONG THE WESTERN FOOTHILLS.  
EXPECT SOME DIURNAL DECREASE TO ~35 MPH GUSTS LATE THIS AFTERNOON.  
GAP AREAS SHOULD SEE ANOTHER INCREASE TONIGHT AS MID LEVEL FLOW  
BACKS TO THE WSW AND REMAINS ON THE ORDER OF 30 KNOTS. GUSTS  
SHOULD REACH 40-45 MPH AND COULD TOUCH 50 MPH AT TIMES INTO  
SATURDAY MORNING. SATURDAY NIGHT WINDS WILL BE PRE-FRONTAL AND  
STAND A BETTER CHANCE (75%) OF EXCEEDING 50 MPH AT LIVINGSTON AND  
NYE. POTENTIAL FOR WIND ADVISORY WILL NEED TO BE MONITORED AND  
SEEMS TO BE 50-50 AT THIS TIME. COLD ADVECTION REDUCES THE GAP  
FLOW AND ENHANCES WESTERLY GUSTS FROM BIG TIMBER TO HARLOWTON  
AFTER 09Z SATURDAY NIGHT.  
 
ARRIVING PACIFIC WAVE LATE SATURDAY NIGHT WILL BRING A LITTLE  
SNOW (1-2") TO THE WESTERN MOUNTAINS BUT JUST A FEW LIGHT RAIN  
SHOWERS AT LOWER ELEVATIONS (PROBABILITY OF 10-20%). CURRENT  
INDICATIONS ARE THAT SURFACE TEMPS WILL WARM SUFFICIENTLY TO KEEP  
PTYPE AS RAIN IN OUR NORTH/NORTHEAST, BUT THE RISK OF LIGHT  
FREEZING RAIN NEAR INGOMAR-MILES CITY WILL NEED TO BE MONITORED  
AS WELL.  
 
BELOW ARE FORECAST AND RECORD HIGH TEMPS FOR TODAY AND SATURDAY.  
 
SITE TODAY RECORD SATURDAY RECORD  
LVM 54 56 (2023) 57 57 (2023)  
BIL 55 58 (1941) 58 57 (1994)  
SHR 58 60 (2023) 60 63 (1933)  
 
JKL  
 
SUNDAY THROUGH FRIDAY...  
 
ABOVE AVERAGE HEIGHTS WILL PERSIST THROUGH THE EXTENDED FORECAST  
WITH WEAK SHORTWAVES EXPECTED TO BRING LITTLE RELIEF. SUNDAY  
MORNING, FOLLOWING SHORTWAVE TROUGHING AND AN ASSOCIATED FRONT,  
INCREASED LOW TO MID LEVEL WINDS AND A PRESSURE GRADIENT WILL  
FAVOR GUSTY WINDS ALONG THE WESTERN FOOTHILLS. SUNDAY, AREAS OF  
LIVINGSTON, BIG TIMBER THROUGH HARLOWTON WILL MOST LIKELY BE  
AFFECTED. CURRENTLY, THERE IS ABOUT A 50% CHANCE OF HITTING 50 MPH  
AT THESE LOCATIONS. ADDITIONAL WEAK SHORTWAVES LOOK TO PASS OVER  
THE REGION MONDAY AND WEDNESDAY WITH NO APPRECIABLE PRECIP. ANY  
PRECIP THAT DOES FALL OVER LOWER ELEVATIONS WILL LIKELY BE RAIN,  
WITH THE MOUNTAINS EXPECTED TO PICK UP A FEW INCHES OF SNOW BY THE  
END OF THE WEEK. WITH THIS PATTERN, PERIODIC GAP WINDS CAN BE  
EXPECTED, BUT OVERALL, NOTHING IS INDICATING PARTICULARLY STRONG  
WINDS AT THIS TIME.  
 
HIGH TEMPERATURES WILL BE IN THE 40S AND LOW 50S THROUGH THE  
PERIOD. TS  
 

 
   
AVIATION
 
 
SW-W WINDS WILL REMAIN GUSTY ALONG THE WESTERN FOOTHILLS THIS  
AFTERNOON, WITH GUSTS OF 30-45 KNOTS AT KLVM, K6S0 & KHWQ. GUSTS  
IN THESE AREAS WILL DECREASE TO 15-25 KNOTS BY EVENING, BUT THEY  
WILL INCREASE AGAIN AT KLVM OUT OF THE SW LATER TONIGHT INTO  
SATURDAY, WITH 30-40 KNOT GUSTS. OTHERWISE, EXPECT WIDESPREAD VFR  
OVER THE NEXT 24 HOURS UNDER BUILDING HIGH PRESSURE ALOFT. JKL  
 

 
   
PRELIMINARY POINT TEMP/POPS
 
 
SAT SUN MON TUE WED THU FRI  
-----------------------------------------------------------  
BIL 034/058 038/052 029/048 028/048 035/049 028/047 031/048  
00/B 00/U 02/R 00/B 31/B 00/B 11/B  
LVM 038/057 039/048 032/047 028/050 031/046 028/046 030/046  
00/N 20/N 03/O 01/N 51/B 01/N 22/O  
HDN 027/054 031/053 025/048 025/049 031/049 024/046 027/048  
00/U 01/B 02/R 10/U 32/R 00/B 11/B  
MLS 021/047 027/048 023/045 026/046 030/045 023/042 025/042  
00/U 12/R 01/B 10/U 11/B 00/B 00/B  
4BQ 026/053 032/049 025/047 028/049 032/046 026/046 027/046  
00/U 01/B 01/B 10/U 11/B 00/B 11/B  
BHK 018/045 025/043 021/042 023/045 026/041 021/042 023/042  
00/B 02/O 00/U 00/U 01/E 00/B 00/B  
SHR 028/060 030/051 023/049 024/052 028/046 023/048 025/048  
00/U 00/B 02/R 10/U 22/O 00/B 11/B  
 

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

 
 

 
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