778
FXUS65 KBYZ 050754
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
154 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.

&&

.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, and this
will be largely dependent on skies clearing. JKL

&&

.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
    8/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
    8/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

&&

.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.

&&

$$
weather.gov/billings