769
FXUS65 KBYZ 150756
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
156 AM MDT MON SEP 15 2025
KEY MESSAGES
- UNSETTLED AND COOLER TODAY INTO WEDNESDAY
- LIGHT SNOW ACCUMULATIONS BEARTOOTH MOUNTAINS ABOVE 10KFT TONIGHT
THROUGH WEDNESDAY MORNING. MAY IMPACT THE HIGHEST ELEVATIONS
ALONG THE BEARTOOTH HIGHWAY.
- BECOMING DRIER WITH SEASONAL TEMPERATURES FOR THE END OF THE
WORK WEEK.
DISCUSSION
AS MENTIONED IN YESTERDAYS DISCUSSION, A PACIFIC SYSTEM IS
CURRENTLY IMPACTING MONTANA WEST OF THE DIVIDE, WITH A FEW
ISOLATED SHOWERS/THUNDERSTORMS LEAKING OVER INTO OUR FORECAST AREA
WEST OF BILLINGS. MAIN THREAT WITH THIS ACTIVITY OVERNIGHT WILL
BE BRIEF GUSTY WINDS (UP TO 45MPH) AND ISOLATED LIGHTNING STRIKES.
THE BRUNT OF THIS SYSTEM WILL ARRIVE MID DAY INTO THE AFTERNOON
HOURS MONDAY AS THE ORIENTATION OF THE SYSTEM BECOMES MORE
NEGATIVELY TILTED FORMING A DEFORMATION AREA ALOFT THAT WILL
ENHANCE LIFT AND SUPPORT INCREASED SHOWER AND THUNDERSTORM
DEVELOPMENT.
WIDESPREAD LIKELY PRECIPITATION CHANCES (50-80%) SPREAD ACROSS
THE FORECAST AREA FROM WEST TO EAST THROUGH THE AFTERNOON INTO THE
EVENING HOURS. ALSO MENTIONED PREVIOUSLY, THIS SYSTEM IS STUCK
OVER THE AREA FOR THE NEXT FEW DAYS DUE TO A HIGH AMPLITUDE
BLOCKING PATTERN OVER EASTERN PORTIONS OF THE US. SO, WILL
CONTINUE TO WITH THE HIGHER PRECIPITATION CHANCES INTO AT LEAST
TUESDAY NIGHT. AS THE DOWNSTREAM BLOCK WEAKENS, PRECIPITATION
CHANCES WILL SLOWLY DIMINISH FROM WEST TO EAST THROUGH WEDNESDAY
EVENING.
PRECIPITATION PROBABILITIES ACROSS THE FORECAST AREA THROUGH
WEDNESDAY:
AT LEAST 0.25 INCHES = 50 TO 90 PERCENT
AT LEAST 0.50 INCHES = 40 TO 80 PERCENT (SOUTH OF I-90/94)
AT LEAST AN INCH = 20 TO 40 PERCENT (NORTH FACING FOOTHILLS
AND ALONG/SOUTH OF US212 SE MONTANA)
TEMPERATURES REACHED THE LOWER 80S MOST AREAS SUNDAY WITH
ABUNDANT SUN. CLOUD COVER AND PRECIPITATION WILL CUT 5 TO 10
DEGREES OFF OF THOSE VALUES TODAY FOR WESTERN AND CENTRAL ZONES,
WHILE SE MONTANA WARMS BACK INTO THE LOWER 80S. EVERYONE ENDS UP
IN THE LOWER TO MID 70S ON TUESDAY EXCEPT FOR THE WESTERN
FOOTHILLS WHERE UPPER MID TO UPPER 60S WILL BE COMMON. SEASONAL
TEMPERATURES IN THE 70S WILL CONTINUE WEDNESDAY. CHAMBERS
AN ADDITIONAL SHORTWAVE TROUGH DROPPING IN FROM THE NORTH WILL
KEEP LOWER HEIGHTS AND CYCLONIC FLOW OVER THE REGION WEDNESDAY
INTO THURSDAY. WITH THIS, A SLIGHT CHANCE OF PRECIPITATION WILL
PERSIST, MAINLY OVER THE PLAINS OF EASTERN MONTANA INTO THURSDAY.
TEMPERATURES HAVE ALSO TRENDED A FEW DEGREES COOLER AGAIN WITH
HIGHS IN THE 60S TO MID 70S ON WEDNESDAY AND THURSDAY NOW. BY
FRIDAY, LOW AMPLITUDE RIDGING LOOKS TO BUILD IN FROM THE WEST.
THIS WILL BRING DRIER AND SLIGHTLY WARMER TEMPERATURES BACK TO THE
REGION GOING INTO THE WEEKEND. ARENDS
AVIATION
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO
MOVE NORTHEAST OVER THE MOUNTAINS AND FOOTHILLS OF WESTERN AND
CENTRAL MONTANA EARLY THIS MORNING. BY THIS AFTERNOON INTO
TONIGHT, ANOTHER ROUND OF SCATTERED SHOWERS AND THUNDERSTORMS IS
EXPECTED ACROSS THE AREA. WITH THIS ACTIVITY, GUSTY WINDS AND
BRIEF MVFR CONDITIONS ARE POSSIBLE UNDER THE STRONGER CELLS. THE
MOUNTAINS WILL ALSO BE OBSCURED AT TIMES TODAY INTO TONIGHT.
ARENDS
PRELIMINARY POINT TEMP/POPS
TDY TUE WED THU FRI SAT SUN
-------------------------------------------------------
BIL 074 052/069 052/075 050/076 049/077 051/082 054/083
4/T 77/T 32/T 00/U 00/U 00/U 01/U
LVM 066 042/066 041/074 043/076 042/079 045/081 047/080
6/T 56/T 11/U 00/U 00/U 01/U 12/W
HDN 077 049/071 049/075 047/077 046/078 047/082 049/084
6/T 76/T 42/T 10/U 00/U 00/U 01/U
MLS 082 054/075 052/075 051/076 050/075 050/080 052/083
3/W 64/T 42/T 11/U 10/U 00/U 00/U
4BQ 080 053/071 052/069 050/071 048/072 048/077 052/081
5/W 63/T 43/T 21/B 10/U 00/U 00/U
BHK 081 051/074 049/072 048/069 047/070 047/076 048/080
1/B 52/W 32/T 22/T 11/B 00/B 00/U
SHR 075 042/067 044/069 042/073 042/075 045/079 047/082
6/T 67/T 55/T 21/U 00/U 00/U 11/U
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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