773
FXUS65 KBYZ 151502
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
802 AM MST MON DEC 15 2025
KEY MESSAGES
- WARMER AND MOSTLY DRIER WEATHER EXPECTED THROUGH MID WEEK.
EXPECT RAPID SNOW MELT THIS WEEK.
- PERIODS OF STRONG WIND FOR FOOTHILLS/GAP LOCATIONS INCLUDING
LIVINGSTON/NYE THROUGH THE FORESEEABLE FUTURE. STRONG WINDS
ACROSS THE ENTIRE AREA WEDNESDAY.
- STRONG WINDS ACROSS THE US-191 CORRIDOR STARTING TONIGHT. CHANCE
OF EXTREME CROSS WINDS (BIG TIMBER TO JUDITH GAP) WEDNESDAY.
- SEVERAL INCHES OF SNOWFALL IS EXPECTED WEDNESDAY IN THE
BEARTOOTH/ABSAROKA AND CRAZY MOUNTAINS, GREATEST ON WEST
ASPECTS.
DISCUSSION
TODAY THROUGH SUNDAY...
SIGNIFICANT WIND IMPACTS EXPECTED THIS WEEK. TEMPS WILL BE
SEASONALLY MILD AND SNOW MELT WILL CONTINUE, ESPECIALLY OVER THE
LOWER ELEVATIONS. WE DO NOT EXPECT ANY SIGNIFICANT HYDRO IMPACTS
FROM THE SNOW MELT AS SOIL MOISTURE AND SHALLOW DEPTH OF FROZEN
GROUND SUGGEST WE CAN HANDLE THE LIQUID WATER RELEASED.
CURRENTLY, THE IDA-LWT PRESSURE GRADIENT IS AROUND 12MB, AND WINDS
ARE GUSTING INTO THE LOW 50S MPH IN THE LIVINGSTON VICINITY.
STRONG SOUTHWEST WINDS WILL CONTINUE FOR THE LIVINGSTON TO NYE
AREA TODAY WITH GUSTS OF 55-65 MPH EXPECTED. HIGHS ARE FORECAST IN
THE 40S AND 50S TODAY FOR MOST AREAS. A WEAK DISTURBANCE WILL
DROP INTO THE REGION TONIGHT INTO TUESDAY, CAUSING PRESSURE
GRADIENTS TO TIGHTEN (IDA-LWT 15-19MB), AND 700MB WINDS TO
INCREASE TO 60-80 KTS. WINDS WILL INCREASE ALONG THE WESTERN
FOOTHILLS THIS EVENING, CONTINUING INTO TUESDAY MORNING. WIND
GUSTS TO 75 MPH ARE EXPECTED FROM LIVINGSTON TO NYE, WITH GUSTS OF
50 TO 65 MPH ALONG THE US-191 CORRIDOR. HIGH WIND WARNINGS HAVE
BEEN ISSUED FOR THE WESTERN FOOTHILLS, IN EFFECT FROM THIS EVENING
THROUGH TUESDAY MORNING/EARLY AFTERNOON. WILL NEED TO MONITOR THE
POTENTIAL FOR WIND HIGHLITES EXTENDING A BIT FARTHER EAST, AS
SOME OF THE HI-RES GUIDANCE INDICATES HIGHER GUSTS INTO GOLDEN
VALLEY AND WESTERN STILLWATER COUNTIES.
WINDS BACK OFF TUESDAY AFTERNOON INTO THE EVENING AS THE MID LEVEL
WINDS DECREASE. THE DECREASE IN WINDS WILL BE SHORT-LIVED
HOWEVER, AS PRESSURE GRADIENTS TIGHTEN LATE TUESDAY NIGHT INTO
WEDNESDAY AHEAD OF A CLIPPER SYSTEM CROSSING INTO THE REGION.
PRESSURE GRADIENTS ARE FORECAST TO INCREASE TOWARDS 18-20MB, WITH
700MB WINDS INCREASING TO 65-85 KTS. THIS IS SOMEWHAT SIMILAR TO
LAST TUESDAY (12/9) WHEN EXTREME GUSTS WERE REPORTED IN THE
MOUNTAINS AND FOOTHILLS (97 MPH AT BIG TIMBER). THIS WILL LIKELY
BE THE PERIOD OF HIGHEST WINDS WITH BIG TIMBER AND HARLOWTON
HAVING 80% CHANCE FOR GUSTS OVER 60 MPH, AND LIVINGSTON NEAR A
100% CHANCE. AN ASSOCIATED COLD FRONT IS EXPECTED TO MOVE THROUGH
THE REGION WEDNESDAY AFTERNOON AND EVENING SPREADING STRONG WINDS
TO THE REST OF THE AREA. THERE IS THE POTENTIAL FOR WIND GUSTS OF
40-60 MPH OVER THE PLAINS, THOUGH THERE IS SOME UNCERTAINTY, GIVEN
EXPECTED PRECIPITATION AND UPWARD MOTION ASSOCIATED WITH THE
WAVE. RAIN/SNOW SHOWERS WILL SPREAD OVER THE AREA WEDNESDAY INTO
WEDNESDAY NIGHT BRINGING LIGHT RAIN/SNOW AMOUNTS TO THE LOWER
ELEVATIONS, AND SEVERAL INCHES OF SNOW TO THE WEST ASPECTS IN THE
MOUNTAINS.
COOLER CONDITIONS ARE FORECAST FOR THURSDAY BEHIND THE CLIPPER,
WITH HIGHS BACK DOWN INTO THE 30S TO LOWER 40S. ANOTHER PERIOD OF
STRONG FOOTHILLS WIND IS PROGGED FOR THURSDAY NIGHT INTO FRIDAY,
AHEAD OF A POTENTIAL COLD FRONT HEADING INTO THE WEEKEND. WHILE
THERE REMAINS A LOT OF UNCERTAINTY, THERE IS CURRENTLY MODERATE
CHANCES FOR PRECIPITATION, GREATEST OVER THE MOUNTAINS AND
FOOTHILLS. STP
AVIATION
UPDATED 15Z.
MAIN AVIATION HAZARD OVER THE NEXT 24 HOURS IS WIND, WHICH WILL
BE STRONGEST ALONG THE WESTERN FOOTHILLS. AT KLVM, GUSTS TO 45
KNOTS THIS MORNING WILL INCREASE TO 50-55 KNOTS THIS AFTERNOON
THEN 60-65 KNOTS TONIGHT. FROM K6S0 TO KHWQ, GUSTS 40-45 KNOTS
TODAY ARE EXPECTED TO INCREASE TO 50-55 KNOTS TONIGHT. FURTHER
EAST AT LOWER ELEVATIONS THERE WILL BE PERIODS OF LLWS, ESPECIALLY
TONIGHT, IMPACTING KBIL, KMLS & KBHK. OTHER THAN WIND, WIDESPREAD
VFR WILL PERSIST THRU TONIGHT. JKL
PRELIMINARY POINT TEMP/POPS
TDY TUE WED THU FRI SAT SUN
-------------------------------------------------------
BIL 046 037/047 035/048 021/039 032/051 025/039 024/039
1/U 10/N 06/O 11/B 24/O 42/S 11/B
LVM 059 041/052 039/050 025/043 034/051 024/041 022/041
1/N 11/N 19/O 13/S 46/O 52/S 22/S
HDN 046 033/046 030/050 015/038 029/051 022/039 022/038
1/U 21/B 16/O 11/B 24/O 53/S 21/B
MLS 042 032/043 028/045 009/031 024/045 017/034 019/035
0/U 10/B 13/O 20/B 23/O 31/B 11/B
4BQ 048 035/047 030/051 014/036 029/050 023/038 024/039
0/U 10/B 13/O 10/B 12/O 42/S 11/B
BHK 045 032/044 025/045 003/025 015/043 012/030 014/034
0/U 10/N 13/O 30/B 22/O 31/B 11/B
SHR 053 032/051 030/056 016/039 027/054 023/039 019/041
0/U 10/B 06/O 20/B 02/O 42/S 11/B
BYZ WATCHES/WARNINGS/ADVISORIES
MT...HIGH WIND WARNING IN EFFECT FROM 5 PM THIS AFTERNOON TO 2 PM
MST TUESDAY FOR ZONES 63-68-141-172-228.
WIND ADVISORY IN EFFECT UNTIL 5 PM MST THIS AFTERNOON FOR
ZONES 65-66.
HIGH WIND WARNING IN EFFECT FROM 5 PM THIS AFTERNOON TO 11 AM
MST TUESDAY FOR ZONES 65-66.
WY...NONE.
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