491
FXUS65 KBYZ 130722
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
122 AM MDT SAT SEP 13 2025
KEY MESSAGES
- A GOOD CHANCE FOR PRECIPITATION TODAY. THERE IS A 30% (WEST) TO
80% (EAST)CHANCE FOR HALF AN INCH PLUS OF PRECIPITATION.
- HIGHS AROUND 70 TODAY.
- MAINLY DRY AND WARMER (70S TO LOW 80S) SUNDAY AND MONDAY.
- COOLER TEMPERATURES AND WETTER CONDITIONS RETURN WITH ANOTHER
STORM SYSTEM MONDAY NIGHT INTO WEDNESDAY.
DISCUSSION
THROUGH SUNDAY NIGHT...
MODELS CONTINUE TO ADVERTISE A WET DAY TODAY ACROSS THE FORECAST
AREA AS A BROAD UPPER TROF SITS OVER THE REGION AND CHUNKS OF
ENERGY ROTATE THROUGH THE AREA FROM THE SOUTHWEST. THE BIGGEST
SHIFT IN THE MODELS IS COMING FROM THE HI-RES MODELS WHICH ARE
SHOWING A STRONGER PRECIPITATION SIGNATURE FROM BILLINGS TO THE
WEST COMPARED TO WHAT THE SYNOPTIC MODELS WERE ADVERTISING OVER
THE PAST FEW DAYS. NBM IS SLOWER TO PICK UP ON THIS TREND IN THE
PROBABILITIES DUE TO TIME LAG CONSTRAINTS, BUT THE LATEST
PROBABILITIES FROM WPC ARE SHOWING 50 TO 60% CHANCES FOR MORE THAN
HALF AN INCH OF PRECIPITATION BY SUNDAY MORNING IN A FAIRLY BROAD
BAND FROM BILLINGS TO REED POINT AND FROM THE BEARTOOTH FOOTHILLS
NORTH TO RYEGATE AND ROUNDUP. AS MENTIONED YESTERDAY ONE OF THE
FACTORS HOLDING DOWN PRECIPITATION POTENTIAL WEST OF BILLING WAS A
LACK OF EASTERLY UPSLOPE WINDS TO COUNTER THE MID LEVEL DOWNSLOPE
SOUTHWEST WINDS. THE LATEST RUNS ARE SHOWING A STRONGER EAST TO
NORTHEAST LOW LEVEL WIND COMBINED WITH A DEVELOPING MID LEVEL
BAROCLINIC LEAF TAKING SHAPE IN THE EARLY MORNING HOURS AND
LASTING INTO SATURDAY AFTERNOON. RAP BUFKIT SOUNDINGS SHOW A
SATURATED SOUNDING OVER BILLINGS UP TO 300MB, STRONG OMEGA, AND
EVEN SOME SKINNY CAPE DRIVING THIS HI-RES MODEL PRECIPITATION
INTENSIFICATION. PROBABILITIES FOR AN INCH OR MORE OF
PRECIPITATION FOR COLUMBUS ARE NOW AT 21%, 5% IN BIG TIMBER, 12%
IN RED LODGE, 25% IN BILLINGS, AND 15% IN ROUNDUP. EVENING SHIFT
GOT THE BALL ROLLING ON INCREASING POPS AND QPF FOR THIS AREA AND
WILL CONTINUE THAT TREND WITH THIS FORECAST PACKAGE.
FOR AREAS EAST OF BILLINGS AND ESPECIALL OVER MOST OF SE MONTANA
RAIN HAS BEEN ONGOING SINCE THIS MORNING AND CONTINUE TO SEE AREAS
OF MODERATE TO HEAVY RAINFALL IN SPOTS WITH STRONGER
THUNDERSTORMS. THERE WILL BE SOME BREAKS IN PRECIPITATION THROUGH
THIS AFTERNOON AS A JET INDUCED DRY SLOTS SHIFTS THROUGH THE AREA
FROM THE SOUTH, BUT OVERALL NO BIG CHANGES TO THE FORECAST FOR
THIS AREA TODAY.
TEMPERATURES WILL BE HELD DOWN BY CLOUD COVER AND PRECIPITATION
TODAY WITH MOST AREAS IN THE UPPER 60S TO LOWER 70S, COOLEST IN
THE WEST.
ENERGY WITH THIS SYSTEM SHIFTS NORTH AND EAST OF THE AREA SATURDAY
NIGHT ENDING SIGNIFICANT PRECIPITATION CHANCES OVER THE AREA.
SUNDAY WILL BE GENERALLY DRY AND WARMER WITH HIGHS BACK IN THE MID
70S TO LOWER 80S. CAN'T RULE OUT A FEW STRAY SHOWERS GIVEN THE
AMOUNT OF PRECIPITATION FORECAST TO FALL OVER THE NEXT 24 HOURS,
BUT THIS ACTIVITY SHOULD BE LIGHT. CHAMBERS
MONDAY THROUGH FRIDAY...
ENSEMBLES ARE IN GOOD AGREEMENT OF A LOW PRESSURE SYSTEM MOVING
INTO SOUTHWEST MT EARLY MONDAY. THIS WILL BRING MODERATE CHANCES
OF PRECIPITATION TO THE REGION AS WELL AS COOLER CONDITIONS
THROUGH TUESDAY NIGHT. ABOVE AVERAGE ATMOSPHERIC MOISTURE SHOULD
ASSIST IN BRINGING MODEST PRECIPITATION TO THE REGION. CURRENTLY,
THERE IS A 30-60% CHANCE OF GETTING AT LEAST A QUARTER INCH OF
RAIN ACROSS THE AREA DURING THIS TIME FRAME. CHANCES FOR STRONG
THUNDERSTORMS DURING THIS TIME IS LOW, BUT WEAK EMBEDDED
THUNDERSTORMS CAN'T BE RULED OUT. ANOTHER FACTOR TO NOTE IS THAT
WITH THE COOLER NATURE OF THIS SYSTEM, THE HIGHEST PEAKS OF THE
ABSAROKA/BEARTOOTHS ARE EXPECTED TO GET LIGHT SNOW ACCUMULATIONS
(LESS THAN 1 INCH). TOWARDS MID WEEK, THERE IS SOME UNCERTAINTY
ON HOW THIS LOW WILL INTERACT WITH THE PREVIOUS LOW THAT STICKS
AROUND SOUTH CENTRAL CANADA. IF THE ENERGY SHIFTS WESTWARD, FAR
EASTERN MT COULD SEE SOME PRECIPITATION (CURRENTLY A 10% CHANCE).
ENSEMBLES THEN BRING IN SHORTWAVE RIDGING FOR THE END OF THE
PERIOD GIVING WAY TO WARMER AND DRYER CONDITIONS.
HIGH TEMPERATURES WILL BE IN THE 70S AND LOW 80S MONDAY, COOLING
TO THE 60S AND LOW 70S FOR TUESDAY AND WEDNESDAY. TEMPERATURES
WILL REBOUND BACK INTO THE 70S AND LOW 80S FOR THE REMAINDER OF
THE PERIOD. TS
AVIATION
SCATTERED SHOWERS WITH ISOLATED EMBEDDED THUNDERSTORMS WILL MOVE
UP INTO SOUTH CENTRAL MT OVERNIGHT AND LAST THROUGH THE MORNING.
SHOWERS AND THUNDERSTORMS WILL BECOME MORE ISOLATED INTO THE
AFTERNOON HOURS, GRADUALLY DISSIPATING THROUGH THE EVENING. LOW
CEILINGS INTO THE EARLY MORNING HOURS WILL CREATE MVFR/IFR
CONDITIONS. TS
PRELIMINARY POINT TEMP/POPS
TDY SUN MON TUE WED THU FRI
-------------------------------------------------------
BIL 069 051/081 055/080 053/073 051/078 052/079 051/078
8/T 21/U 13/T 55/T 21/U 00/U 11/B
LVM 070 043/079 046/072 043/071 042/078 044/078 045/076
4/T 11/U 15/T 43/T 10/U 00/U 12/W
HDN 071 048/082 051/081 051/072 048/078 047/080 047/079
7/T 21/U 02/W 55/T 21/U 00/U 01/B
MLS 074 053/079 054/082 054/075 051/077 050/077 050/076
7/T 21/B 11/U 45/T 31/U 11/U 10/U
4BQ 073 053/074 053/080 054/071 051/073 049/076 050/075
4/T 21/B 11/U 54/T 32/T 10/U 00/U
BHK 073 051/074 051/081 051/074 048/074 047/075 047/073
7/T 22/W 21/B 35/T 32/T 11/U 10/B
SHR 071 044/077 046/078 045/068 043/075 045/078 046/078
4/T 11/B 13/T 56/T 32/T 10/U 01/U
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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