820 FXUS65 KBYZ 061222 AFDBYZArea Forecast Discussion National Weather Service Billings MT 622 AM MDT Mon Oct 6 2025
.KEY MESSAGES...
- Chilly with localized fog early this morning.
- Building high pressure aloft brings dry and warmer weather through Friday.
- Next reasonable chance of precipitation is the weekend.
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.DISCUSSION... Today through Tuesday Night...
Upper trof dropping slowly thru WY continues to bring some very light precip to our south as of 07z, mainly over the Bighorns, but some light showers may eke into far southern Powder River/Carter before it exits entirely. Once we get past ~15z, dry conditions will persist through the remainder of the period as high pressure builds over the region. There is a low risk (20%) of localized valley fog early this morning. Existing cloud cover is preventing temps from dropping too quickly but skies are mostly clear in the far east, and we are starting to see breaks along portions of the western foothills. Dew point spreads are quite low at this hour (4F or less) so fully expect there to be some fog by sunrise. Something to monitor.
07z temperatures are in the 30s to lower 40s. Again depending on cloud cover, a good portion of the region should be in frost or freeze territory by daybreak. For many locations this will be the chilliest morning seen so far this fall, which says more about the warm early fall than the coolness of this air mass.
Expect high temperatures in the 50s today and 60s Tuesday as the ridge brings persistent downslope warming. Frost and freeze potential will be more localized tonight due the downslope gradients and warm advection. Lows will reach the upper 20s to lower 40s, coolest in sheltered valleys. Tuesday night will be milder yet.
When skies clear be sure to check out the snow-topped mountains.
JKL
Wednesday through Monday...
There is now good agreement that the cutoff upper level low pressure system off the west coast will lead to increased heights across Montana. This will create temperatures around 5 degrees above average Wednesday and Thursday (70 F) before increasing to 5 to 15 degrees above average Friday and Saturday (70-80 F).
There is good ensemble agreement that an upper level trough will drop into the region next weekend and bring a pattern change to wetter and cooler conditions. Precipitation chances return Saturday and last through Monday. Currently, the NBM is giving a 30-70% chance for getting greater than 0.25 inches of precipitation across the region. Given how far out this system is, it is difficult to provide further details at this time. Torgerson
.AVIATION...
Area of light rain in the far southeast corner of MT will dissipate by ~15z. Localized fog and low stratus will produce MVFR-IFR early this morning, and fog is being reported at Harlowton as of 12z, but the chance of fog impacting a TAF site is quite low (10%). The risk of fog will end by 15z. Expect a transition to widespread VFR by late morning. This afternoon through tonight will see VFR and mostly clear skies as high pressure aloft builds over the region. JKL
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.PRELIMINARY POINT TEMP/POPS...
Tdy Tue Wed Thu Fri Sat Sun ------------------------------------------------------- BIL 058 040/066 044/072 043/070 043/076 052/076 044/058 0/U 00/U 00/U 00/U 00/U 13/W 55/W LVM 056 029/066 033/070 036/071 038/075 044/070 034/053 0/U 00/U 00/U 00/U 01/U 35/W 66/W HDN 058 031/067 034/073 036/071 040/077 046/079 042/060 0/U 00/U 00/U 00/U 00/U 12/W 54/W MLS 059 034/067 039/073 040/072 042/079 050/080 045/060 0/U 00/U 00/U 00/U 00/U 01/U 43/W 4BQ 056 034/065 040/070 041/071 044/078 054/080 045/060 0/B 00/U 00/U 00/U 00/U 01/U 33/W BHK 059 031/066 037/073 040/071 040/074 049/080 041/061 0/U 00/U 00/U 00/U 00/U 00/U 32/W SHR 056 028/066 031/071 036/071 039/079 046/078 037/059 1/B 00/U 00/U 00/U 00/U 12/W 44/W
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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