198
FXUS65 KBYZ 161809
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1109 AM MST TUE DEC 16 2025
KEY MESSAGES
- CONFIDENCE GROWING FOR A SIGNIFICANT AND WIDESPREAD HIGH WIND
EVENT TONIGHT THROUGH WEDNESDAY. GUSTS MAY APPROACH 70 MPH AT
LOWER ELEVATIONS TOMORROW AFTERNOON AND EVENING. THE HIGHEST
GUSTS MAY CAUSE TREE, POWER LINE AND STRUCTURAL DAMAGE!
- FOR TONIGHT AND WEDNESDAY, WIND GUSTS OF 65 TO 80 MPH POSSIBLE
ALONG THE FOOTHILLS, AND 50 TO 70 MPH ACROSS LOWER ELEVATIONS IN
THE AFTERNOON AND EVENING.
- SEVERAL INCHES OF SNOWFALL EXPECTED WEDNESDAY IN THE BEARTOOTH/
ABSAROKA AND CRAZY MOUNTAINS, GREATEST ON WEST ASPECTS.
UPDATE
MOUNTAIN WAVE WINDS AT RED LODGE AND SHERIDAN HAVE DIMINISHED
SINCE EARLY THIS MORNING, AS WE ARE NOW SEEING LEE SIDE PRESSURE
RISES FROM A PASSING WEAK SHORTWAVE. THIS WAVE HAS ALSO ALLOWED
WINDS TO DECREASE AT LIVINGSTON AND NYE. FOR THIS REASON HAVE
CANCELLED THE HIGH WIND WARNING FOR THESE LOCATIONS. THE US-191
CORRIDOR CONTINUES TO SEE NEAR 60 MPH GUSTS AND WILL LET THE
WARNING CONTINUE INTO THE AFTERNOON.
THE MAIN EVOLVING STORY IS AN EXPECTED SIGNIFICANT AND WIDESPREAD
HIGH WIND EVENT LATE TONIGHT AND TOMORROW. A HIGH WIND WATCH
CURRENTLY EXISTS AND WILL MAKE NO CHANGES AT THIS TIME. THAT SAID,
THE COMBINATION OF SYNOPTIC SCALE SUBSIDENCE AND EXPECTED DEEP
MIXING INTO VERY STRONG LOW-MID LEVEL FLOW WILL YIELD HIGH GUSTS
ACROSS LOWER ELEVATIONS TOMORROW AFTERNOON AND EVENING. CONFIDENCE
IS GROWING FOR GUSTS INTO THE 60-70 MPH RANGE AT LOWER ELEVATIONS.
PLEASE PLAN YOUR TRAVEL AND OUTDOOR ACTIVITIES ACCORDINGLY, AND
BE AWARE THAT THE STRONGEST GUSTS MAY CAUSE TREE, POWER LINE AND
STRUCTURAL DAMAGE.
JKL
DISCUSSION
TODAY THROUGH MONDAY...
WINDS HAVE BEEN GUSTING INTO THE 50S TO NEAR 70 MPH AT TIMES OVER
THE WESTERN FOOTHILLS OVERNIGHT AS TIGHT PRESSURE GRADIENTS (IDA-
LWT CURRENTLY 18MB) AND MID-LEVEL WINDS INCREASE (700MB WINDS OF
50-80 KTS). MOUNTAIN WAVE ACTIVITY ALONG PORTIONS OF THE
BEARTOOTHS AND THE LEE SIDE OF THE BIGHORNS HAS BROUGHT WIND GUSTS
AT TIMES OF 40-60 MPH. EXPECT THE STRONG WINDS TO PERSIST ALONG
THE FOOTHILLS THROUGH THE MORNING, BEFORE GRADUALLY DECREASING
INTO THE AFTERNOON. WIND GUSTS OF 50 TO 75MPH REMAIN POSSIBLE
THROUGH THE MORNING, STRONGEST NEAR LIVINGSTON AND NYE. HAVE MADE
NO CHANGES TO THE HIGH WIND WARNINGS CURRENTLY OUT ALONG THE
FOOTHILLS THROUGH THIS MORNING/EARLY AFTERNOON.
THE BRIEF DECREASE IN WINDS THIS AFTERNOON WILL BE SHORT-LIVED
HOWEVER, AS PRESSURE GRADIENTS TIGHTEN TONIGHT INTO WEDNESDAY
AHEAD OF A CLIPPER SYSTEM CROSSING INTO THE REGION. PRESSURE
GRADIENTS ARE FORECAST TO INCREASE TOWARDS 16-20MB, WITH 700MB
WINDS INCREASING TO 65-85 KTS. STRONG TO DAMAGING WINDS ARE
POSSIBLE ALONG THE FOOTHILLS TONIGHT THROUGH WEDNESDAY. THIS SET-
UP CURRENTLY APPEARS SOMEWHAT SIMILAR TO THE RECENT EVENT THAT
BROUGHT EXTREME GUSTS TO THE BIG TIMBER AREA AND WILL BE SOMETHING
TO KEEP AN EYE ON. CURRENTLY, THERE IS A 70-90% CHANCE OF GUSTS
OVER 60 MPH ALONG THE US-191 CORRIDOR FROM BIG TIMBER TO HARLOWTON
AND A 30-50% CHANCE OF GUSTS GREATER THAN 70 MPH. THE PROBABILITY
FOR WIND GUSTS OF 75 MPH OR GREATER FOR LIVINGSTON AND NYE IS
AROUND 60%. A COLD FRONT MOVING THROUGH THE REGION WEDNESDAY
AFTERNOON WILL SPREAD THE GUSTY WINDS ACROSS THE PLAINS, WITH
GUSTS AROUND 40-60 MPH COMMON THROUGH THE LATE EVENING/NIGHT AS
STRONG PRESSURE RISES PERSIST BEHIND THE FRONT. A HIGH WIND WATCH
HAS BEEN ISSUED FOR MOST OF THE AREA STARTING TONIGHT OR WEDNESDAY
MORNING, CONTINUING INTO WEDNESDAY NIGHT.
THE COLD FRONT WILL SPREAD RAIN/SNOW SHOWERS (40-70%) ACROSS THE
AREA WEDNESDAY INTO WEDNESDAY EVENING, WITH RAIN BECOMING MOSTLY
SNOW BY LATE AFTERNOON/EVENING. OVER THE ABSAROKA/BEARTOOTH
MOUNTAINS, THERE IS A 70% CHANCE OF AT LEAST 6" OF SNOW THROUGH
WEDNESDAY NIGHT. THURSDAY INTO FRIDAY, UPPER LEVEL FLOW TURNS MORE
WESTERLY AND IS ACCOMPANIED BY ANOTHER PUSH OF PACIFIC MOISTURE.
THERE IS STILL DISAGREEMENT ON THE EXACT DETAILS, BUT THERE IS
CURRENTLY A 60% CHANCE OF AT LEAST 12" OF SNOW OVER THE
ABSAROKA/BEARTOOTH MOUNTAINS THURSDAY EVENING THROUGH SATURDAY
MORNING. ANOTHER PERIOD OF STRONG WINDS FOR THE FOOTHILLS IS
POSSIBLE THURSDAY NIGHT INTO FRIDAY, WITH CURRENT PROBABILITIES OF
60 MPH WINDS AT 40-80%.
HIGHS WILL BE GENERALLY IN THE 40S AND 50S TODAY AND WEDNESDAY.
THEN, BEHIND THE COLD FRONT, HIGHS WILL DROP INTO MOSTLY 30S AND
40S FOR THURSDAY. TEMPERATURES WARM BRIEFLY FRIDAY BACK INTO THE
40S AND 50S BEFORE AGAIN DECREASING TO 30S AND 40S THROUGH THE
WEEKEND. ARCHER/STP
AVIATION
WEST WINDS REMAIN FAIRLY STRONG ALONG THE WESTERN FOOTHILLS FROM
K6S0 TO KHWQ, BUT THESE WINDS WILL DECREASE GRADUALLY (TO 25-40
KNOTS) THIS AFTERNOON. LOWER ELEVATION WINDS HAVE ALREADY
DECREASED SINCE EARLY THIS MORNING.
CONFIDENCE IS GROWING FOR A SIGNIFICANT AND WIDESPREAD HIGH WIND
EVENT TONIGHT THROUGH WEDNESDAY. WINDS WILL INTENSIFY AGAIN ALONG
THE WESTERN FOOTHILLS BEGINNING BY LATE EVENING, SPREADING TO THE
SOUTHERN FOOTHILLS LATE TONIGHT AND EARLY WEDNESDAY, THEN ACROSS
THE REGION TOMORROW LATE MORNING THROUGH AFTERNOON. ALL TAF SITES
WILL BE IMPACTED BY STRONG WIND GUSTS. EXPECT GUSTS OF 55-70 KNOTS
AT KLVM LATE TONIGHT AND WEDNESDAY MORNING, AND 45-60 KNOTS AT
KBIL, KMLS & KSHR WEDNESDAY. NORTHEAST ASPECTS OF THE BEARTOOTH,
PRYOR & BIGHORN MOUNTAINS MAY SEE PERIODIC STRONG SURFACING
MOUNTAIN WAVES LATE TONIGHT AND WEDNESDAY MORNING (50% CHANCE OF
50+ KNOT GUSTS), AND THIS WILL NEED TO BE MONITORED.
VFR WILL OTHERWISE CONTINUE ACROSS THE REGION. A COLD FRONT WILL
BRING LOWER ELEVATION RAIN SHOWERS AND SOME MOUNTAIN SNOW
TOMORROW, AND THE HIGH ELEVATIONS WILL BE OBSCURED.
JKL
PRELIMINARY POINT TEMP/POPS
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 054 035/051 026/041 034/051 026/040 024/039 024/045
1/B 06/W 00/B 14/O 53/S 22/S 22/O
LVM 056 039/051 024/044 034/050 027/040 022/043 030/050
1/N 2+/W 03/S 56/O 63/S 22/O 34/O
HDN 052 030/051 019/040 031/050 025/040 021/038 021/042
2/W 17/W 10/B 24/O 63/S 22/O 12/O
MLS 046 027/047 012/033 026/044 019/033 018/036 020/037
1/B 24/W 20/B 22/O 42/S 21/B 11/E
4BQ 051 031/052 018/036 030/049 025/039 024/038 024/045
1/B 14/W 20/B 02/O 52/S 21/B 11/B
BHK 046 025/048 006/026 017/043 012/030 013/035 015/037
1/N 14/W 40/B 22/O 41/B 21/B 11/E
SHR 054 029/056 019/038 026/054 023/038 018/040 022/050
0/B 07/W 10/B 02/O 53/S 21/B 11/B
BYZ WATCHES/WARNINGS/ADVISORIES
MT...HIGH WIND WATCH IN EFFECT FROM WEDNESDAY MORNING THROUGH LATE
WEDNESDAY NIGHT FOR ZONES
29>34-36-37-42-57-58-138-139-169-170-173-235.
HIGH WIND WATCH IN EFFECT FROM 11 PM MST THIS EVENING THROUGH
WEDNESDAY EVENING FOR ZONE 56.
HIGH WIND WARNING IN EFFECT UNTIL 2 PM MST THIS AFTERNOON FOR
ZONES 63-141-172-228.
HIGH WIND WATCH IN EFFECT FROM LATE TONIGHT THROUGH LATE
WEDNESDAY NIGHT FOR ZONES 63-141-172-228.
HIGH WIND WATCH IN EFFECT FROM 8 PM MST THIS EVENING THROUGH
WEDNESDAY EVENING FOR ZONES 65-66.
HIGH WIND WATCH IN EFFECT FROM 11 PM MST THIS EVENING THROUGH
LATE WEDNESDAY NIGHT FOR ZONES 67-68.
WY...HIGH WIND WATCH IN EFFECT FROM WEDNESDAY MORNING THROUGH LATE
WEDNESDAY NIGHT FOR ZONE 199.
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