496
FXUS65 KBYZ 172331
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
431 PM MST TUE DEC 17 2024
KEY MESSAGES
- PERIOD OF STRONG, GUSTY WINDS LATE TONIGHT INTO THURSDAY
MORNING, FIRST OVER THE WESTERN FOOTHILLS THEN OVER THE PLAINS.
- CHANCE FOR MIXED PRECIPITATION IN THE FAR NORTH-EAST, WEDNEDSAY
NIGHT. LOW CHANCE FOR FREEZING RAIN, ALONG WITH COLD ARCTIC AIR
AND STRONG NW WINDS.
- ABOVE NORMAL TEMPERATURES FOR MUCH OF THE AREA FRIDAY INTO
EARLY NEXT WEEK.
DISCUSSION
TODAY THROUGH THURSDAY AFTERNOON...
SNOW SHOWERS WILL CONTINUE INTO THE EVENING HOURS IN THE EASTERN
COUNTIES. PATCHY FOG IS POSSIBLE TONIGHT, FROM BILLINGS TO THE FAR
EAST AND AREAS OF FOG ARE POSSIBLE IN CARTER AND FALLON.
OVERNIGHT LOWS WILL BE IN THE SINGLE DIGITS TO MID 20S (COLDEST
ALONG THE DAKOTA BORDERS). THERE IS A LOW TO MODERATE (15-60%)
CHANCE FOR PRECIPITATION IN THE ABSAROKA/BEARTOOTHS TONIGHT (THE
BEST CHANCE WILL BE FOR W-SW FACING SLOPES). ACCUMULATIONS WILL BE
LIGHT, WITH 1-2 INCHES OF SNOW POSSIBLE FOR COOKE CITY. HIGH
TEMPERATURES ON WEDNESDAY WILL BE IN THE 40S TO LOW 50S, WARMEST
FROM SHERIDAN TO BILLINGS AND WEST.
MAIN FOCUS IN THE SHORT TERM FORECAST PERIOD IS STRONG AND GUSTY
WINDS IN THE WESTERN MOUNTAINS AND FOOTHILLS. A FAVORABLE PRESSURE
GRADIENT BETWEEN IDAHO FALLS AND LEWISTOWN IS DEVELOPING THIS
AFTERNOON, STRENGTHENING TO AROUND 20MB OVERNIGHT. ALONG WITH
THIS, A BUILDING RIDGE AND VERY STRONG 700MB FLOW UP TO 70 KNOTS
WILL RESULT IN WIND GUSTS OF 70-75 MPH IN THE WESTERN GAP AND
FOOTHILL AREAS. AS A RESULT, A WIND ADVISORY WILL GO INTO EFFECT
AT 11 PM TONIGHT FOR LIVINGSTON AND NYE. A HIGH WIND WARNING WILL
GO INTO EFFECT FOR HARLOWTON, BIG TIMBER, JUDITH GAP, AND MELVILLE
AT 5 AM WEDNESDAY. THE SW-NE ORIENTED PRESSURE GRADIENT FOR
LIVINGSTON WILL BEGIN TO SHIFT TO A W-E ORIENTATION DUE TO A
SHORTWAVE TROUGH AND SURFACE COLD FRONT DROPPING THROUGH THE
REGION, WEDNESDAY EVENING. WIND GUSTS FOR THE LIVINGSTON AND NYE
AREAS WILL LIKELY APPROACH THE HIGH WIND WARNING THRESHOLD, SO WE
WILL MONITOR THE NEED FOR A POTENTIAL PRODUCT UPGRADE.
WITH THIS SHORTWAVE, AN INCREASED CHANCE FOR PRECIPITATION
(15-40%) WILL SWEEP ACROSS THE WESTERN MOUNTAINS AND THE NORTH-
EAST PARTS OF THE FORECAST AREA, TOMORROW AFTERNOON THROUGH THE
EVENING. THE STRONG WINDS WILL BEGIN TO DECREASE LATE TOMORROW
NIGHT INTO THURSDAY MORNING, WITH THE PRESSURE GRADIENT AND 700MB
FLOW WEAKENING. THE AFOREMENTIONED PRODUCTS ARE SET TO EXPIRE AT 2
AM THURSDAY.
THERE IS SOME CONCERN WITH PRECIPITATION TYPE AND TIMING TOMORROW
NIGHT FOR NORTHERN ROSEBUD, CUSTER, AND FALLON COUNTIES, WITH
SOUNDINGS HINTING AT MIXED PRECIPITATION. INITIALLY, SOUNDINGS
DEPICT A STRONG LOW-LEVEL INVERSION THAT WILL HELP PREVENT MUCH OF
THE STRONG MIDLEVEL WINDS FROM MIXING TO THE SURFACE. HOWEVER,
WITH THE FRONTAL PASSAGE, THE INVERSION GETS ERASED QUICKLY, AND
THEN IT IS A MATTER OF HOW COLD SURFACE TEMPERATURES ARE AND IF
THE ENVIRONMENT CAN WETBULB. THERE IS A LACK OF MOISTURE IN THE
EAST, WHICH IS ANOTHER MITIGATING FACTOR. SOME MODELS ARE
DEPICTING FREEZING RAIN, WHILE OTHERS KEEP SURFACE TEMPS ABOVE
FREEZING, RESULTING IN RAIN. CURRENT FORECAST HAS A RAIN- SNOW MIX
SO MAKE SURE TO KEEP AN EYE ON FUTURE UPDATES TO THE FORECAST.
THE REST OF THURSDAY WILL BE DRY AND HIGH TEMPERATURES WILL BE IN
THE 20S TO UPPER 40S (COLDEST IN THE EAST NEAR BAKER).
MATOS
THURSDAY NIGHT THROUGH TUESDAY...
THURSDAY NIGHT THROUGH TUESDAY
MAIN FORECAST CONCERNS IN THE LONG TERM ARE ON ABOVE NORMAL
TEMPERATURES, OCCASIONAL PRECIPITATION CHANCES, MAINLY IN THE
MOUNTAINS, AND THEN FOCUS TURNS TO A POTENTIALLY MORE ACTIVE PATTERN
BY THE MIDDLE PART OF NEXT WEEK.
HIGH CONFIDENCE IN RIDGING BUILDING OVER THE REGION LATE THIS WEEK
INTO SATURDAY WITH MUCH ABOVE NORMAL TEMPERATURES AND DRY WEATHER
ANTICIPATED. THERE IS A 50 TO 60 PERCENT CHANCE THAT HIGHS COULD
EXCEED 50 DEGREES AT KBIL SATURDAY INTO SUNDAY. A FEW WEAK
SHORTWAVES LOOK TO MOVE THROUGH THE REGION SUNDAY INTO MONDAY THEN
FORECAST CONFIDENCE DROPS OFF AS WPC CLUSTERS START TO SHOW SOME
DIFFERENCES IN THE 500 MB PATTERN BY THE MIDDLE PART OF NEXT WEEK,
BUT THERE APPEARS TO BE SOME SIGNALS FOR A MORE ACTIVE WEATHER
PATTERN.
AVIATION
THE MAIN AVIATION CONCERN FOR THE PERIOD WILL BE VERY STRONG
WINDS. THIS WILL ESPECIALLY BE AN ISSUE AT KLVM AS WINDS ARE
EXPECTED TO PICK UP VERY QUICKLY TOMORROW EARLY MORNING AND BY 15Z
WE COULD BE SEEING GUSTS AS HIGH AS 65-70KTS. OTHER LOCATIONS OUT
WEST SUCH AS KHWQ COULD ALSO SEE GUSTS OVER 45KTS. FURTHER EAST
WINDS WIL BE LIGHTER BUT STILL BREEZY. KSHR SHOULD GUST TO 25KTS
TOWARDS THE END OF THE PERIOD. KBIL WILL SEE BREEZY CONDITIONS
START TO PICK UP AFTER 15Z WHERE GUSTS COULD TOP 30KTS FROM 250
DEGREES BY 22Z.
SOME MOUNTAIN OBSCURATION IS ALSO POSSIBLE WITH
LIGHT SNOW IN THE HIGHER ELEVATIONS, AS WELL AS A SLIGHT CHANCE
(30%) FOR PATCHY FOG IN ARAES SUCH AS KSHR AND KMLS.
WMR
PRELIMINARY POINT TEMP/POPS
WED THU FRI SAT SUN MON TUE
-----------------------------------------------------------
BIL 022/050 031/043 026/050 030/051 034/053 033/051 032/053
01/N 00/U 00/B 00/B 01/B 01/B 01/B
LVM 026/050 028/047 029/052 033/054 034/049 033/050 033/054
12/R 00/N 00/B 00/U 11/B 11/N 12/R
HDN 020/048 025/040 021/048 024/049 027/053 027/051 026/051
11/E 10/U 00/B 00/B 11/B 01/B 01/B
MLS 013/042 013/024 010/039 018/037 022/045 025/045 025/044
22/O 10/U 00/B 00/B 01/B 00/B 00/B
4BQ 018/045 023/033 017/046 023/046 027/048 028/049 026/049
11/B 10/U 00/B 00/B 01/B 01/B 00/U
BHK 007/039 005/021 003/035 015/036 019/040 023/042 023/044
21/E 30/N 00/B 00/B 01/B 00/B 00/U
SHR 017/052 025/044 021/054 026/054 029/054 026/053 026/054
00/B 00/U 00/B 00/U 01/B 01/B 00/B
BYZ WATCHES/WARNINGS/ADVISORIES
MT...HIGH WIND WARNING IN EFFECT FROM 5 AM WEDNESDAY TO 2 AM MST
THURSDAY FOR ZONES 34-42-63-141-172-228.
WIND ADVISORY IN EFFECT FROM 11 PM THIS EVENING TO 2 AM MST
THURSDAY FOR ZONES 65-66.
WY...NONE.
WEATHER.GOV/BILLINGS
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