603
FXUS65 KBYZ 241118
AFDBYZ
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
418 AM MST WED DEC 24 2025
KEY MESSAGES
- ABOVE NORMAL TEMPERATURES EXPECTED THROUGH FRIDAY.
- WEAK COLD FRONT MAY BRING A SHOT OF RAIN/SNOW CHRISTMAS DAY,
BUT NO BIG STORMS OR IMPACTS EXPECTED.
- COLDER WITH CHANCE FOR RAIN/SNOW FRIDAY NIGHT INTO SATURDAY.
CHANCE FOR STRONG WINDS AND POTENTIAL TRAVEL HAZARDS FOR THIS
PERIOD.
- PERSISTENT LIGHT TO MODERATE SNOW FOR THE BEARTOOTH/ABSAROKA
MOUNTAINS THURSDAY THROUGH SATURDAY.
DISCUSSION
TODAY THROUGH WEDNESDAY...
PATCHY FOG DEVELOPED OVERNIGHT, MAINLY IN THE RIVER VALLEYS OF
THE EASTERN ZONES. HOWEVER, WARMER AIR AND WESTERLY FLOW WAS
DOMINANT IN THE BEARTOOTH FOOTHILLS WITH TEMPS IN THE 40S. WE
EXPECT TO SEE THE WARMER AIR AND DOWNSLOPE SLOWLY PUSH INTO THE
CENTRAL ZONES BY LATE TONIGHT/MORNING ERODING THE FOG FOR ALL BUT
THE MOST EASTERN RIVER VALLEYS. ANY LINGERING FOG SHOULD SLOWLY
DISSIPATE AFTER SUNRISE.
MUCH ABOVE AVERAGE TEMPERATURES AND DRY CONDITIONS ARE EXPECTED
TODAY WITH HIGH TEMPERATURES IN THE 40S AND 50S. OROGRAPHIC SNOW
WILL BEGIN TO DEVELOP OVER THE ABSAROKA/BEARTOOTH RANGES LATE
TONIGHT INTO CHRISTMAS DAY AS A SHORT WAVE AND ASSOCIATED WEAK
COLD FRONT TRACK ACROSS THE AREA. THIS WILL PRODUCE A QUICK SHOT
OF ISOLATED TO SCATTERED RAIN SHOWERS AT THE LOWER ELEVATIONS AND
IN THE FOOTHILLS (20-40% CHC) FOR CHRISTMAS DAY. NOTABLE IMPACTS
ARE NOT EXPECTED WITH ONLY A SLIGHT CHANCE OF GETTING GREATER THAN
0.1 INCHES OF LIQUID. TEMPS CHRISTMAS DAY AND FRIDAY WILL
CONTINUE TO SEE MUCH ABOVE AVERAGE TEMPERATURES WITH 40S TO MID
50S EXPECTED.
MOIST SOUTHWESTERLY FLOW INTO THE MOUNTAINS THURSDAY WILL PERSIST
AND PRODUCE LIGHT TO MODERATE SNOW OVER THE WEST FACING SLOPES
INTO THE WEEKEND. THIS PROLONGED PERIOD OF LIGHT TO MODERATE SNOW
WILL GRADUALLY PILE UP THE SNOW THROUGH SATURDAY. TOTALS FROM 6 TO
12 INCHES WILL BE COMMON WITH A 50% CHANCE FOR GREATER THAN 12
INCHES OF SNOW OVER THE 72 HOUR PERIOD OVER THE HIGHEST PEAKS.
AN UPPER LEVEL TROUGH WILL TRACK ACROSS THE MONTANA/CANADIAN
BORDER LATE FRIDAY NIGHT BEFORE DROPPING DOWN INTO THE HIGH
PLAINS OF EASTERN MT AND THE DAKOTAS SATURDAY. TEMPS WILL DROP
DOWN TO WHAT IS TYPICALLY NORMAL FOR THIS TIME OF YEAR IN THE
30S. STRONG FORCING ASSOCIATED WITH THE FRONTAL PASSAGE WILL
SPREAD A BAND OF SNOW SOUTHWARD THROUGH OUR CWA DURING THE DAY. IT
COULD BE A RATHER INTENSE BAND OF PRECIPITATION, BUT WILL BE A
PRETTY QUICK SHOT AND IS NOT LIKELY TO AMOUNT TO MUCH
ACCUMULATION IF ANY OVER THE PLAINS. MODELS DO SHOW IT HANGS UP
OVER THE NORTH FACING FOOTHILLS OF THE BEARTOOTHS AND BIG HORNS
LATE IN THE DAY SUPPORTED BY DECENT UPSLOPE. OUR CURRENT FORECAST
HAS LESS THAN AN INCH ACCUMULATION IN SOUTHERN BIG HORN COUNTY
AND IN THE RED LODGE FOOTHILLS, WITH ONLY A 10-20% CHANCE OF AN
INCH OR MORE. HOWEVER, WE WILL NEED TO WATCH TRENDS HERE AS WE
CANNOT RULE OUT AN INCH OR TWO OF QUICK ACCUMULATION AFFECTING
US-212 NEAR RED LODGE, AND NEAR FORT SMITH NEAR THE BIGHORNS. IN
ADDITION, PATTERN RECOGNITION SUGGEST STRONG WIND POTENTIAL FOR
THE PLAINS SATURDAY. PARTICULARLY OVER THE MT/DAKOTAS BORDER WITH
NW GUSTS 30-45 MPH POSSIBLE. PRE-FRONTAL WESTERLY WINDS MAY GUSTS
45-55 MPH IN THE GAP AREAS OF THE WESTERN FOOTHILLS FRIDAY INTO
EARLY SATURDAY AS WELL.
THE COLDER AIR MASS WILL SIT OVER US SUNDAY WITH HIGHS RANGING
FROM UPPER 30S WEST TO UPPER TEENS ALONG THE DAKOTAS BORDER.
ENSEMBLES AGREE THAT UPPER LEVEL RIDGING AND ABOVE AVERAGE
TEMPERATURES RETURN MONDAY, PUSHING TEMPERATURES BACK INTO THE
40S AND 50S FOR THE FIRST PART OF THE NEXT WORK WEEK. BT
AVIATION
12Z DISCUSSION...
THE FOG HAS NOT FORMED AS FORECAST THIS MORNING DUE IN PART TO AN
UNFAVORABLE WIND DIRECTION. IF WINDS ARE ABLE TO SHIFT SLIGHTLY,
IN ADDITION TO THE HIGH CLOUDS MOVING OUT, A BRIEF PERIOD OF IFR
CONDITIONS REMAIN POSSIBLE AT KBIL BEFORE 15Z; OTHERWISE, EXPECT
VFR TO PREVAIL. FOG HAS BEEN OBSERVED AT TIMES IN RIVER VALLEYS
(KOOU/K1S3) WHERE IT IS SLIGHTLY MORE LIKELY TO FORM AGAIN PRIOR
TO 15Z. THIS MEANS THAT KMLS ALSO HAS A SLIGHT CHANCE OF SEEING A
PERIOD OF IFR CONDITIONS.
IN SHORT, VFR CONDITIONS WILL PREVAIL UNLESS SPECIFIC INGREDIENTS
ARE MET TO FORM SOME LOCALIZED FG BEFORE 15Z.
WINDS WILL BE LIGHT AND VARIABLE ACROSS THE REGION FOR THE ENTIRE
PERIOD WITH THE EXCEPTION OF KLVM WHERE WESTERLY WINDS WILL
CONTINUE WITH GUSTS UP TO 25KTS AT TIMES. AFTER 06Z RAIN/SNOW
SHOWERS MOVE INTO THE AREA AROUND KLVM WHICH MAY IMPACT THE
TERMINAL AFTER 09Z. WMR
PRELIMINARY POINT TEMP/POPS
TDY THU FRI SAT SUN MON TUE
-------------------------------------------------------
BIL 051 035/054 036/055 028/037 011/035 023/046 031/050
0/B 12/R 01/B 13/S 00/B 00/B 01/B
LVM 053 040/053 035/049 027/035 015/037 024/046 029/049
0/B 55/R 24/O 23/S 00/B 00/B 01/B
HDN 051 030/050 031/055 025/039 007/031 017/045 027/048
0/B 11/B 00/B 14/O 10/U 00/U 01/B
MLS 039 027/042 028/049 020/033 002/020 010/038 025/043
0/B 01/E 00/B 11/B 00/U 00/B 02/O
4BQ 052 036/053 033/054 028/039 007/025 015/043 028/046
0/U 00/E 00/U 01/B 10/U 00/B 01/B
BHK 043 025/047 026/051 021/033 903/017 005/037 020/040
0/B 00/B 00/U 11/N 10/U 00/B 02/O
SHR 055 032/054 029/054 025/037 006/032 015/046 025/050
0/B 12/R 01/B 13/S 10/U 00/U 01/B
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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