835 FXUS65 KBYZ 051141 AFDBYZArea Forecast Discussion National Weather Service Billings MT 541 AM MDT Sun Oct 5 2025
.KEY MESSAGES...
- Strong weather system continues to impact region with widespread precipitation (including significant mountain snowfall) and cool temps thru the weekend.
- High probability of a frost or freeze tonight.
- Dry and warmer starting Monday.
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.DISCUSSION... Today through Monday Night...
Overall, the forecast remains on track and there are few changes with this issuance. As this discussion is being written, most locations have seen between 0.25-1.00" of precip in the past 24hrs. Snow levels seem to be down to near 7kft, based on current observations, and we should see them fall to near 6kft today...and possibly to 5.5kft by evening. Local snotels show a few inches of accumulation above 8kft, and web camera at Burgess Jct shows accumulating snow as well. Will make no changes to the winter highlights in effect.
Satellite imagery shows the initial shortwave over northeast WY and a Canadian wave dropping thru north central MT. Precip continues from Billings eastward, but there has been a break in the west between waves. Starting to see an increase in radar echoes over our west, and this increasing trend will continue through daybreak. Forcing with the Canadian wave combined with deep upslope flow will keep precip going today, heaviest in our west and south, as conditions turn drier in the east by afternoon. Additional precip should range from less than a quarter inch in our north, to 0.25-0.75" in the west/south, and up to an inch over southern upslope areas.
There remains uncertainty on a potential changeover to wet snow along the foothills in the 5-6kft layer. Red Lodge stands at 40/35F as of 145am, and upstream dew points in north central MT are still in the mid 30s to lower 40s...so not sure wet bulb cooling will be enough to get a changeover. It is going to be largely dependent on how long ascent/precip continues into this evening, after 00z, and models continue to show spread here. That said, high res models do suggest enough cooling for some wet snow at Red Lodge and Story, and will keep forecast in the 0.5-2" range. Accumulation, if it does happen, will likely be on the grass only as roads should stay wet. Will need to monitor this through the day.
As the wave drifts to the southeast we will transition to subsidence/drying tonight. After today`s chilly day (highs mid 40s to mid 50s), there is a high probability of a frost or freeze across the region, but cloud cover could play a role. Western and northern areas are most likely to reach freezing. Current probability of 32F or less at Billings is 40%.
Monday will be sunny/dry with high temps in the 50s. Monday night will be another cool night. Frost/freeze chances will be more limited to sheltered valleys as downslope gradients develop with weak warm advection. Look for lows in the upper 20s to upper 30s.
JKL
Tuesday through Sunday...
Temperatures will rise through Wednesday as above average heights work their way into the region. Temperatures will generally be in the 60s F Tuesday and the 70s F Wednesday. There is a lot more uncertainty in temperatures Thursday through Sunday. This is due to an upper level trough that models agree will impact western CONUS but don`t agree on where it will setup. Some models indicate this upper level trough will stay off the Pacific Coast keeping temperatures up while others show the trough over Montana leading to cooler temperatures. Colder solutions would likely mean temperatures in the 60s F while warmer solutions would mean temperatures in the 70s F.
Despite this trough, there is good agreement that conditions will be dry Tuesday through Friday. Most solutions then show another trough phasing in with the existing one over the weekend. This is expected to bring precipitation chances back to the region. Given how far our this is, not much more can be said about this potential system. Torgerson
.AVIATION...
Slow-moving weather system will continue to produce widespread rain and mountain snow today, especially in the morning with areas of MVFR/IFR. Precip will taper off in the east by afternoon, then elsewhere from north to south in the afternoon & evening. Expect a transition to VFR as precip ends. Mountains will be obscured in snow through the day with drying tonight. There is a low risk (20%) of localized fog late tonight and early Monday. Fog development will be largely dependent on skies clearing and is of low confidence at this time. JKL
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.PRELIMINARY POINT TEMP/POPS...
Tdy Mon Tue Wed Thu Fri Sat ------------------------------------------------------- BIL 049 034/058 039/066 043/071 043/068 041/070 045/074 +/R 20/U 00/U 00/U 01/U 11/U 12/W LVM 047 026/057 028/066 035/069 037/068 036/071 041/071 +/R 20/U 00/U 00/U 11/U 11/U 13/W HDN 052 032/059 032/068 035/073 038/070 037/071 039/076 9/R 20/U 00/U 00/U 00/U 10/U 11/U MLS 057 032/060 034/068 039/073 040/072 042/072 043/076 4/R 00/U 00/U 00/U 00/U 10/U 11/U 4BQ 054 034/057 035/064 041/071 041/071 042/071 046/076 8/R 10/U 00/U 00/U 00/U 00/U 11/U BHK 057 028/059 033/067 038/072 039/071 039/070 043/076 7/R 00/U 00/U 00/U 00/U 00/U 11/U SHR 048 032/056 028/065 033/071 037/071 037/072 041/076 +/R 61/U 00/U 00/U 00/U 10/U 11/U
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.BYZ WATCHES/WARNINGS/ADVISORIES... MT...Winter Storm Warning in effect until 6 PM MDT this evening FOR ZONES 67-68. Winter Weather Advisory in effect until midnight MDT tonight FOR ZONE 171. WY...Winter Weather Advisory in effect until midnight MDT tonight FOR ZONE 198.
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$$ weather.gov/billings
NWS BYZ Office Area Forecast Discussion