489
FXUS65 KBYZ 142113
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
213 PM MST SUN DEC 14 2025
KEY MESSAGES
- WARMER AND MOSTLY DRIER WEATHER EXPECTED THROUGH MID WEEK.
EXPECT RAPID SNOWMELT 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 MONDAY NIGHT.
CHANCE OF EXTREME CROSS WINDS (BIG TIMBER TO JUDITH GAP)
WEDNESDAY.
DISCUSSION
TONIGHT THROUGH SUNDAY...
SIGNIFICANT WIND IMPACTS EXPECTED THIS WEEK. TEMPS WILL BE
SEASONALLY MILD AND WE SHOULD SEE LOTS OF SNOW MELT OCCUR. WE DO
NOT EXPECT ANY SIGNIFICANT HYDRO IMPACTS FROM THE SNOW MELT AS
SOIL MOISTURE AND STILL SHALLOW DEPTH OF FROZEN GROUND SUGGEST WE
CAN HANDLE THE LIQUID WATER RELEASED.
CURRENTLY, PRESSURE GRADIENT OVER THE PARADISE VALLEY AND WESTERN
FOOTHILLS IS AT 14 MB. PROGS INDICATE IT WILL LEVEL OFF A BIT
REST OF TODAY BEFORE INCREASING AGAIN TONIGHT THROUGH MONDAY
NIGHT. SO WIND ADVISORY FOR GAP LOCATIONS LOOKS GOOD WITH GUSTS
50-65 MPH TODAY AND THEN GOING 60-70 MPH TOMORROW. THE THREAT FOR
STRONG WINDS SPREADS TO THE US_191 CORRIDOR (BIG TIMBER TO JUDITH
GAP) MONDAY NIGHT INTO TUESDAY AS 700MB WINDS ARE FORECAST TO
REACH 60-80 KT RANGE. LOCAL GUIDANCE IS GIVING THE US-191 CORRIDOR
A 70% CHANCE OF GETTING A WIND GUST OVER 60 MPH BY TUESDAY
MORNING, AND A 40% CHANCE OF GUSTS OVER 70 MPH FROM LIVINGSTON TO
BIG TIMBER. THUS, THE HIGH WIND WATCH FOR THIS AREA WILL CONTINUE
MONDAY NIGHT THROUGH TUESDAY MORNING. WE MAY NEED TO TWEAK TIMING
A BIT. WINDS WILL BACK OFF LATE TUESDAY THROUGH THE EVENING AS
700MB WIND MAX EXITS AREA.
LATE TUESDAY NIGHT INTO WEDNESDAY WILL SEE WINDS RAM UP AGAIN AS
THE PRESSURE GRADIENT INCREASES TO NEAR 20 MB. ANOTHER WIND MAX AT
700 MB MOVES INTO THE AREA ASSOCIATED WITH A SHORT WAVE TROUGH
TRACKING ACROSS NE MT (ALBERTA CLIPPER SYSTEM) WITH 700 MB WINDS
REACHING THE 65-85 KT RANGE. 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 A 95% CHANCE.
AS THE ASSOCIATED FRONT AND 700MB WINDS SPREAD EAST WEDNESDAY
AFTERNOON AND EVENING WE MAY SEE WINDS 45-55 MPH SPREAD OVER OUR
EASTERN CWA. UPWARD VERTICAL MOTION MAY PREVENT WIDESPREAD HIGH
WINDS (60 MPH PLUS) FROM OCCURRING, BUT CANNOT RULE OUT LOCAL
GUSTS TO AROUND 60 MPH ACROSS THE EAST AS CURRENT PROGGS SHOW
STEEP LAPSE RATES 6.5-8.0 C/KM WITH 850 WINDS UP TO 60 KTS. WE
WILL BE MONITORING THE SITUATION AND FUTURE SHIFTS MAY NEED A HIGH
WIND WATCH FOR OUR EASTERN PLAINS WED AFTN/WED NITE IF PROGGS
CONTINUE THESE TRENDS. A SHOT OF RAIN/SNOW SHOWERS IS ALSO
EXPECTED WITH THIS SYSTEM ALONG THE FRONT. AMOUNTS ARE EXPECTED
TO REMAIN LIGHT WITH THE NBM GIVING LOWER ELEVATIONS A 10-40%
CHANCE OF GETTING GREATER THAN JUST 0.1 INCHES. HOWEVER, WEST
SLOPES IN THE HIGH COUNTRY COULD PICK UP SEVERAL INCHES OF SNOW.
ADDITIONAL PERIODS OF STRONG WINDS ARE POSSIBLE THROUGH
THE END OF THE WEEK, THOUGH THE POTENTIAL IS LESS CLEAR AT THIS
TIME. BT
AVIATION
21Z DISCUSSION...
WINDY CONDITIONS AT KLVM ARE EXPECTED TO CONTINUE THROUGH THE
PERIOD WITH GUSTS OUT OF THE SW TOPPING 50KTS AFTER 05Z. THESE
WINDS MAY REACH PLACES SUCH AS K6S0/K3HT OVERNIGHT AS WELL. DUE TO
A DECENT TEMPERATURE INVERSION LLWS HAS BEEN INCLUDED IN THE TAFS
FOR KSHR/KMLS THROUGH 00Z. VFR CONDITIONS ARE FORECAST TO PREVAIL
FOR THE ENTIRE PERIOD.
KBIL WILL CAN EXPECT 25KT WIND GUSTS OUT OF THE SW THROUGH 00Z;
OTHERWISE NSW IS EXPECTED. WMR
PRELIMINARY POINT TEMP/POPS
MON TUE WED THU FRI SAT SUN
-----------------------------------------------------------
BIL 030/044 037/048 035/050 019/037 029/050 028/040 023/041
00/B 01/B 16/W 11/B 24/W 52/J 11/B
LVM 035/054 041/053 040/050 024/042 031/050 026/040 024/044
00/N 11/N 19/W 13/J 46/W 63/J 12/J
HDN 021/044 033/048 030/050 014/037 026/049 024/039 020/040
00/U 01/B 26/W 21/B 24/W 63/J 11/B
MLS 025/041 033/043 029/045 009/029 021/043 019/035 018/036
00/U 01/B 24/W 30/B 22/W 41/B 10/B
4BQ 026/044 034/048 031/053 014/035 027/049 026/038 023/041
00/U 01/B 13/W 30/B 12/W 42/J 10/B
BHK 024/042 031/042 025/045 004/022 013/041 016/031 015/036
00/U 00/B 24/W 50/B 12/W 31/B 10/B
SHR 026/051 033/052 030/055 015/038 025/053 023/039 019/044
00/U 01/B 06/W 31/B 12/W 53/J 11/B
BYZ WATCHES/WARNINGS/ADVISORIES
MT...HIGH WIND WATCH IN EFFECT FROM MONDAY AFTERNOON THROUGH
TUESDAY MORNING FOR ZONES 63-65-66-68-141-172-228.
WIND ADVISORY IN EFFECT UNTIL 5 PM MST MONDAY FOR ZONES
65-66.
WY...NONE.
WEATHER.GOV/BILLINGS
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