851
FXUS65 KBYZ 050847
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
147 AM MST Fri Dec 5 2025

.KEY MESSAGES...

- Periods of moderate to heavy snow in the Beartooth-Absaroka and
  Crazy Mountains through the weekend. Heaviest snow on west to
  northwest aspects.

- Generally windy along the western foothills through the weekend,
  with gusts of 30 to 50 mph.

- A couple waves of light snow in the east, from Miles City to
  Baker and Ekalaka, could cause travel difficulties. Highest
  chances of snow are late tonight and Saturday morning, then late
  Saturday night and early Sunday.

- High confidence for a period of strong winds along the western
  foothills Monday night and Tuesday. This will coincide with much
  above normal temperatures through the first half of next week.

&&

.DISCUSSION...

Through next Thursday...

Very complex weather pattern through the weekend. Have made no
changes to the Winter Highlights for area mountains.

Satellite imagery shows a shortwave dropping thru central MT in NW
flow aloft. Though steepest lapse rates of 7-8c/km are further
east, we are seeing snow showers over the western mountains &
foothills, over to the Pryors & Bighorns. Gardiner web cameras
suggest maybe an inch of new snow. Snow will lessen thru the
morning as the wave departs, but could see some lighter snow
showers linger w/ some diurnal instability over the mountains and
in the east. Attention will then turn to the stronger upstream
shortwave currently just off the BC coast, which has a significant
Pacific moisture tap.

Before diving into specifics, want to point out that complexities
with our weekend weather will revolve around a wavering Canadian
surface boundary, which will periodically backdoor toward but
likely not reach our western foothills. This will have obvious
impacts on temperatures and where overrunning snowfall sets up. It
also means persistently gusty downslope winds along the western
foothills. The one sure thing is that mountain snowfall will
remain periodically heavy on W-NW aspects.

WEEKEND WIND. Upstream wave will induce a period of lee side
pressure falls later today, which will shift from NW to SE
tonight. Ascent and instability aren`t ideal for wind, but still
looks like a period of 30-50 mph gusts in the usual windy spots in
the west (Livingston, Big Timber, Nye & Harlowton) tonight and
Saturday morning. Another ripple of elevated wind gusts, of
similar magnitudes, is expected Saturday night into Sunday. The
probability of 50+ mph gusts is ~45% each time.

WEEKEND SNOW. Additional snow amounts of 10-20" expected on west
aspects of the western mountains from now through the weekend
(heaviest prior to Sunday). Bighorns and Pryors will see
occasional slop over when flow shifts enough to the NW with each
wave passage. The BC wave will provide some overrunning snow
tonight & Saturday. This will be brief from Harlowton to Billings
as downslope winds take over, but a 1-2" accumulation is a fair
bet in the northeast from Forsyth to Miles City, Baker and Ekalaka
(locations which will stay solidly on the cold side of the
surface boundary). The probability of exceeding 2" is about 25%.
Then, on the back side of the wave as a cold front backdoors
through Billings, areas of light snow showers are possible late
Saturday into Saturday night. Later Saturday night into Sunday the
boundary shifts back east and more overrunning light snow is
possible in our far east.

TEMPS THROUGH WEEKEND. Ranging from the 20s to lower 30s in the
east to mid 30s to mid 40s along western foothills. Billings could
see rapid fluctuations tomorrow, with a high near 40F followed by
a late afternoon drop potentially into the 20s. Something to
watch.

NEXT WEEK. With confidence the first half of next week will be
much warmer than normal across the entire region, as the Canadian
boundary exits and we are dominated by downslope winds. Main
impact to monitor is a period of potentially very strong winds
along the western foothills Monday night and Tuesday. Local
guidance shows a >90% chance of 60+ mph gusts at the gap
locations, and EC ensembles show a mean gust of 60 mph at Big
Timber (a very strong signal indeed). There will be a Pacific
wave/moisture too, meaning more snow for the western mountains and
some rain showers at lower elevations. Look for temps in the 40s
to lower 50s Monday & Tuesday, followed by some cooling for
Wednesday. We could see another Canadian front and chance of snow
by next Thursday...but a lot of spread in the ensembles after a
confidently mild first half of the week.

JKL

.AVIATION...

An area of MVFR ceilings, with occasional local reductions to
IFR, will spread across the area east of KBIL this morning and may
impact KSHR through 18Z and KMLS and KBHK through the TAF period.
Lingering showers will taper off this morning before the next
round moves in from the west late afternoon/early evening and
spreads east overnight. Under the heaviest snow showers, expect
occasional ceiling and visibility reductions to IFR/LIFR. Archer

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Sat     Sun     Mon     Tue     Wed     Thu
-------------------------------------------------------
BIL 038 028/039 021/041 029/043 040/050 029/041 029/042
    1/B 54/W    20/N    10/B    14/W    54/W    54/W
LVM 039 030/041 027/041 029/045 041/050 026/041 030/045
    3/J 94/W    30/N    30/N    25/W    65/W    54/W
HDN 038 023/037 017/042 024/044 030/048 026/041 025/040
    2/J 87/W    50/B    20/B    25/W    65/W    65/W
MLS 032 017/027 010/035 020/039 030/045 023/036 023/034
    2/J 88/S    51/B    10/B    34/W    42/J    52/W
4BQ 034 021/035 014/039 023/041 030/047 026/038 026/037
    3/J 35/J    20/B    10/B    14/W    53/W    43/W
BHK 030 013/022 004/032 016/038 025/042 017/032 015/032
    3/J 39/S    34/J    00/B    34/W    42/J    42/J
SHR 037 024/040 018/043 021/046 026/051 023/039 023/041
    4/J 55/W    30/B    10/B    13/W    64/W    54/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Winter Storm Warning in effect until 2 PM MST Saturday FOR
      ZONES 67-68.
     Winter Weather Advisory in effect until 2 PM MST this
      afternoon FOR ZONE 171.
WY...None.

&&

$$
weather.gov/billings