349
FXUS65 KBYZ 142100
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
300 PM MDT SUN SEP 14 2025
KEY MESSAGES
- UNSETTLED AND COOLER MONDAY AND TUESDAY.
- BECOMING DRIER WITH SEASONAL TEMPERATURES WEDNESDAY THROUGH
FRIDAY.
DISCUSSION
AN ISOLATED SHOWER OR TWO IS POSSIBLE THIS AFTERNOON AND EVENING
ALONG THE DAKOTAS BORDER. OTHERWISE, EXPECT DRY CONDITIONS THROUGH
THIS EVENING. AN UPPER LOW/TROUGH AND SURFACE COLD FRONT WILL MOVE
INTO THE REGION FROM THE SOUTHWEST OVERNIGHT. THIS WILL INCREASE
THE CHANCE FOR PRECIPITATION (15 TO 30%), MAINLY IN THE FAR
WEST-SOUTHWEST ZONES LATE TONIGHT INTO MONDAY MORNING. THE CHANCE
FOR PRECIPITATION WILL THEN INCREASE (30-70%) ACROSS THE AREA
THROUGH MONDAY AS THE LOW AND ANOTHER SURFACE COLD FRONT MOVE
THROUGH SOUTHEASTERN MT. THIS CHANCE FOR PRECIP (30-70%) IS
FORECAST TO LAST INTO WEDNESDAY MORNING. SHOWERS AND EMBEDDED
WEAK THUNDERSTORMS ARE EXPECTED AND THE CHANCE FOR STRONGER
THUNDERSTORMS IS VERY LOW. PRIMARY CONCERNS WILL BE LOCALLY HEAVY
RAINFALL UNDER STORMS AND MAYBE SOME GUSTY WINDS.
TEMPERATURES WILL BE BE IN THE 70S TO LOW 80S MONDAY (COOLER IN
THE WEST), BEFORE COOLING INTO THE UPPER 60S AND LOW 70S ON
TUESDAY THANKS TO THE SECOND COLD FRONT. TEMPERATURES ARE FORECAST
TO DROP TO OR BELOW FREEZING IN THE ABSAROKA/BEARTOOTHS MONDAY
NIGHT THRU TUESDAY MORNING. SNOW LEVELS WILL DROP TO AROUND 10KFT,
RESULTING IN THE CHANCE FOR LIGHT SNOW ACCUMULATIONS. THE CHANCE
FOR AN INCH OF SNOWFALL IS 40-60% ABOVE 10KFT WHILE THERE IS A
10-20% CHANCE ON WYOMING'S SIDE OF THE BEARTOOTH PASS.
PRECIPITATION AMOUNTS TONIGHT THROUGH TUESDAY RANGE FROM
0.10" TO 0.70", WITH THE HIGHEST AMOUNTS ASSOCIATED WITH HEAVIER
SHOWERS IN THE MOUNTAINS AND LOCATIONS EAST AND SOUTH OF BILLINGS.
WEDNESDAY ONWARD, THERE IS SOME UNCERTAINTY WITH THE PATTERN BUT
IT LOOKS TO BE A TRANSITION DAY. THE MAIN TROUGH ENERGY IS
DEPICTED DIGGING INTO THE CENTRAL PLAINS, BUT PIECES OF ENERGY
MAY WRAP BACK INTO THE SOUTHEAST. A LOW AMPLITUDE RIDGE IS SHOWN
TRYING TO BUILD OVER THE CONTINENTAL DIVIDE SIMULTANEOUSLY. RIGHT
NOW, THERE IS MODERATE CONFIDENCE THAT THE FORMER DEPICTION WILL
KEEP A LINGERING CHANCE FOR PRECIPITATION AND AROUND NORMAL
TEMPERATURES.
THERE IS MODERATE UNCERTAINTY THURSDAY INTO THE WEEKEND AS
ENSEMBLES SHOW THE MONDAY LOW STALLING IN THE PLAINS, WITH PIECES
OF ENERGY MOVING THROUGH EASTERN MT. FOR NOW, THE CHANCE FOR
PRECIPITATION IS LOW (GENERALLY BELOW 30%) AND HIGH TEMPERATURES
ARE FORECAST TO BE IN THE 70S.
MATOS
AVIATION
A COLD FRONT WILL CROSS THE AREA TONIGHT INTO MONDAY MORNING.
THERE WILL BE ISOLATED SHOWERS AND THUNDERSTORMS (15-20% CHANCE)
WEST OF KHWQ-K6S0, INCLUDING THE KLVM AREA BETWEEN 00Z AND 06Z
MONDAY. (THIS CHANCE WAS LOW ENOUGH TO KEEP SHRA MENTION FOR THIS
PERIOD OUT OF TAF FOR NOW.) THERE WILL ALSO BE A PERIOD LASTING UP
TO 4 HOURS OF WNW WINDS GUSTING TO 30-40 KT OR SO OVERNIGHT IN
SOUTH CENTRAL MT, ESPECIALLY AT HIGHER ELEVATION TERMINALS SUCH AS
KLVM, KHWQ, AND K6S0, THOUGH IT IS UNCLEAR HOW MUCH OF THIS WILL
REACH THE LOWER ELEVATIONS (VALLEYS) FARTHER EAST, SUCH AS KBIL.
ON MONDAY, SCATTERED SHOWERS AND THUNDERSTORMS (20-70% CHANCE,
GREATEST NEAR THE MOUNTAINS) WILL OVERSPREAD SOUTH CENTRAL MT AND
NORTH CENTRAL WY FROM WEST TO EAST. MOUNTAINS WILL BE OBSCURED.
DESPITE THE PRECIPITATION, CEILINGS AND VISIBILITY ARE EXPECTED TO
REMAIN VFR AT AREA TERMINALS, WITH LESS THAN A 10% CHANCE OF
CONDITIONS BECOMING MVFR THERE THROUGH 00Z TUESDAY. RMS
PRELIMINARY POINT TEMP/POPS
MON TUE WED THU FRI SAT SUN
-----------------------------------------------------------
BIL 057/076 055/070 053/076 051/077 049/076 051/078 052/080
05/T 77/T 21/U 00/U 00/U 11/B 11/U
LVM 045/070 045/068 044/076 044/079 044/077 045/078 045/077
16/T 65/T 11/U 00/U 01/U 12/W 22/W
HDN 052/078 051/071 050/076 048/078 046/077 046/078 048/081
03/T 77/T 41/U 10/U 00/U 11/B 21/U
MLS 054/084 056/075 053/077 051/076 049/074 049/077 050/080
01/U 65/T 42/W 10/U 10/U 11/B 11/U
4BQ 054/080 054/070 053/072 050/073 048/072 049/075 051/077
01/U 65/T 52/W 11/U 00/U 10/B 11/U
BHK 052/082 051/074 050/075 046/071 046/070 045/073 047/077
10/B 43/T 42/W 11/B 11/B 11/B 11/U
SHR 048/076 045/068 045/072 043/074 042/075 043/077 046/079
06/T 67/T 53/W 11/U 00/U 11/U 21/U
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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