683 FXUS65 KBYZ 132135 AFDBYZArea Forecast Discussion...Corrected National Weather Service Billings MT 335 PM MDT Sat Sep 13 2025
.KEY MESSAGES...
- 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.
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.DISCUSSION...
Through Sunday night...
Upper low and trough continue to move east this afternoon. A weak MCV/ 700mb low slowly moving through southcentral MT right now, as seen by radar reflectivity and satellite. Showers and isolated thunderstorms remain possible (20-60%) through this afternoon, with the best chance in the NW zones and the SW mountains. There is a low chance for showers and a weak thunderstorm along the Dakotas border late tonight into Sunday afternoon, with upper low energy moving into the Northern Plains out of the Southern Plains.
Temperatures for the rest of today will be in the 60s and 70s. A shortwave ridge will briefly visit the region Sunday bringing drier conditions and temperatures back into the 70s and 80s.
Matos
Monday through Friday...
Ensembles are in good agreement of a low pressure system moving through the PNW into southwest MT early Monday. This will bring a moderate to high chance for precipitation through Tuesday. Currently, the latest NBM guidance depicts a 30 to 60% chance of at least 0.25" of rainfall Monday through Tuesday. The chance for strong thunderstorms remains low with unfavorable dynamics, but a few weak and embedded thunderstorms can`t be ruled out.
This system will also be cooler than last weeks, with 850mb temperature anomalies around -5C. This will also bring the chance for light snowfall to the highest peaks of the Absaroka/Beartooths, through Tuesday night. The chance for at least an inch of snowfall is 20-50% Monday afternoon through Tuesday morning.
There is uncertainty in the pattern midweek, with a few models showing piece of energy dropping through northern Montana from a low in Canada. Other models show general troughing digging along the Rockies. Ensembles do show better confidence in ridging later next week resulting in warmer and drier 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. PM/TS
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.AVIATION...
Lingering showers and isolated thunderstorms will taper off across the area tonight. Expect mainly VFR conditions through the TAF period but cannot rule out some patchy fog late tonight into early Sunday morning, mainly at KMLS, thanks to lighter surface winds, recent rainfall, and low level moisture in place. Lingering cloud cover will likely limit radiational fog development over eastern Montana.
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.PRELIMINARY POINT TEMP/POPS...
Tdy Sun Mon Tue Wed Thu Fri ------------------------------------------------------- BIL 069 051/081 056/077 054/071 051/078 051/080 052/078 3/T 10/U 13/T 45/T 21/U 00/U 01/B LVM 071 043/079 045/069 043/071 042/078 044/080 045/078 1/B 11/U 25/T 44/T 10/U 00/U 12/W HDN 071 047/081 051/079 051/071 048/078 047/080 048/080 2/T 10/U 02/T 55/T 31/U 10/U 01/B MLS 075 053/080 055/081 054/073 051/076 049/077 051/079 3/T 10/B 11/B 34/T 31/U 10/U 11/U 4BQ 072 053/075 054/079 054/068 051/073 049/074 051/078 1/B 10/E 11/U 44/T 32/W 10/U 00/U BHK 073 051/073 052/080 051/073 048/074 046/074 046/075 1/B 12/W 21/B 33/T 31/U 11/U 10/U SHR 071 044/079 047/076 046/068 043/074 044/078 046/080 1/U 10/U 03/T 56/T 32/W 10/U 01/U
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.BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None.
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$$ weather.gov/billings
NWS BYZ Office Area Forecast Discussion