399
FXUS65 KBYZ 100934
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
234 AM MST Wed Dec 10 2025

.KEY MESSAGES...

- A wintry mix of rain and snow, with pockets of light freezing
  rain, possible today; precipitation will track from west to
  east.

- Another period of strong winds along the foothills west of
  Billings this afternoon into Thursday. Gusts in excess of 60 mph
  are likely from Livingston to Big Timber and Harlowton.

- Cold front brings colder temperatures and snow back to the area
  late Thursday into Saturday. Rapidly falling temps combined with
  accumulating snow may result in a flash freeze and treacherous
  travel conditions by Thursday evening.

- Greatest snow accumulations Thursday night into Saturday are
  expected to be over the plains, generally from Ryegate and
  Billings eastward to Miles City and Broadus, where there is a
  30-60 percent chance of at least 6 inches of snow.

- Warmer and drier weather expected to return by Sunday.

&&

.DISCUSSION...
Today through next Tuesday...

A very active week of weather continues...BE READY!

It`s been a quiet weather night between systems, but we are
already starting to see hints of warm advection precip in our
west, courtesy of a very moist Pacific flow streaming through the
PacNW and northern Rockies. Main issue for today is the expected
west-to-east period of mixed precip associated with a warm front.
Surface temps are key as low levels will become warm enough to
produce rain after a brief period of wet snow...so any lingering
pockets of sub-freezing air at the surface would yield freezing
rain. Current surface analysis shows mostly mid 30s along the
foothills but from Billings eastward and in the Musselshell valley
we see temps in the mid 20s to lower 30s as of 2am. Models have
trended a bit slower w/ the precip`s eastward progression, and
this could benefit by allowing for surface warming in the central
and east before it rains. Something to monitor through the day.
Will make no changes to the Winter Weather Advisory to cover
today`s risk of mixed precip.

As today`s precip shifts east we will return to a strong downslope
regime along the western foothills, and all indications are that
the mid level flow and pressure gradient will support highlight
level wind gusts this afternoon into Thursday. The gap locations
should see gusts to 70 mph tonight, while gusts to 65 mph impact
the US-191 corridor (not quite the magnitudes we saw early
Tuesday). Have upgraded the High Wind Watch to a Warning for Big
Timber to Harlowton and Judith Gap, and made no changes to the
Wind Advisory for the gap locations (Livingston & Nye). The strong
winds could/should persist until the late Thursday fropa arrives.

Today and Thursday will be very warm over the west half of our
cwa, with highs in the 50s expected. Temps could reach 60F in the
pre-frontal time on Thursday. Eastern areas will see mid 30s and
40s, still quite a bit warmer than normal.

We will see a strong Canadian cold front arrive late Thursday
afternoon and evening, and this timing is pretty well agreed upon
by models. For Billings, expect a wind shift near 3-5pm.
Overrunning snow should develop quickly behind the fropa (remember
the very moist Pacific flow?) and temps will crash hard. As an
example, Billings could see temps in the upper 50s at 3pm then
upper 20s by 6pm, and perhaps teens before midnight. Ramifications
of this include a potential flash freeze with roads turning icy
then snow-covered. The Thursday evening commute may be quite
difficult so please plan your day accordingly!

Turning to snowfall itself, the main change to note with models
tonight is the secondary cold push and overrunning potential
Friday night and Saturday are looking weaker...thus potentially a
quicker shift in snow to the NE and overall slightly less
accumulation. Heaviest amounts will be east of the foothills (high
confidence there) and ensemble QPF is generally in the 0.50-0.80"
range in an area from Harlowton to Billings and Crow Agency
eastward to Miles City and Broadus. Expect snow ratios to become
healthy as the cold deepens and should yield a 6-12" snowfall
where it is heaviest. Quick glance at the Garcia method shows
mixing ratios of 2-3 g/kg (there`s that very moist Pacific flow
again) which would give an estimate of 10" over a 24-hr period.
The kicker here is that not everyone will see this much snowfall.
A best guess at this time would take the heaviest snow in a NW-SE
axis between Billings and Miles City. Obviously, a small deviation
in the depth of the cold, or the Friday night/Saturday portion,
would alter the forecast. Will make no changes to the Winter Storm
Watch in effect for most lower elevations. Western foothills like
Livingston and Red Lodge will see a little snow as the cold front
arrives, but that should be fairly short-lived.

Colder than normal temps (teens and 20s) should hold throughout
Friday and Saturday, with some uncertainties arriving by the
latter. It is also a tough call along the immediate western
foothills. If a shallow east wind reaches Livingston, which it
should, then guidance will prove to be way too warm. Elevations
above ~6kft will be largely untouched by this air mass, but the
moisture fetch and orographic lift will produce some more
mountain snowfall.

All signs point to the Pacific flow and above normal heights
becoming dominant by Sunday and through much of next week. Thus,
expect a rapid return to above normal temps and mainly dry
conditions.

JKL

.AVIATION...

A band of rain/snow showers will track west to east today. For
central and eastern locations, including KBIL, KSHR, and KMLS,
there is a 20% chance for pockets of freezing rain as the band
moves through. MVFR to IFR conditions are possible with the
precipitation. Mountains will be obscured during periods of heavy
snowfall. Southwest winds will increase over the foothills this
afternoon, with gusts around 50-60 kts by this evening through
Thursday morning. Archer

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Thu     Fri     Sat     Sun     Mon     Tue
-------------------------------------------------------
BIL 052 045/059 017/020 011/023 012/045 029/046 035/049
    6/W 14/W    88/S    32/S    00/B    00/B    01/B
LVM 054 048/058 032/041 029/047 034/053 034/051 038/051
    6/W 14/W    76/O    21/N    00/B    00/B    13/W
HDN 049 041/057 015/021 009/022 007/041 021/043 027/047
    8/W 26/W    88/S    43/S    10/B    00/B    01/B
MLS 042 034/046 007/012 001/012 003/036 021/037 025/045
    8/W 55/W    46/S    83/S    00/B    00/B    01/B
4BQ 045 037/053 014/019 010/019 010/042 024/042 029/047
    7/W 44/W    66/S    53/S    00/U    00/B    00/B
BHK 037 027/043 002/009 904/011 902/037 021/040 024/045
    8/J 95/W    33/S    93/S    00/B    00/B    00/B
SHR 049 036/059 018/031 015/034 018/052 026/051 029/052
    7/W 13/W    75/S    22/S    00/U    00/B    01/B

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory in effect until 11 AM MST this
      morning FOR ZONES 29-34-42-56-63-66-141-170-172-173-228-235.
     Winter Storm Watch in effect from Thursday afternoon through
      Saturday morning FOR ZONES
      29>34-36-37-42-57-58-63-68-138-141-172-173-228-235.
     Winter Weather Advisory in effect from 8 AM this morning to 5
      PM MST this afternoon FOR ZONES 30>32-36-57-58-138-169.
     Winter Weather Advisory in effect from 2 PM this afternoon to
      8 PM MST this evening FOR ZONES 33-37.
     High Wind Warning in effect from 2 PM this afternoon to 5 PM
      MST Thursday FOR ZONES 63-141-172-228.
     Wind Advisory in effect from 11 AM this morning to 5 PM MST
      Thursday FOR ZONES 65-66.
     Winter Storm Warning in effect until 5 PM MST this afternoon
      FOR ZONE 67.
WY...Winter Weather Advisory in effect from 8 AM this morning to 5
      PM MST this afternoon FOR ZONE 199.
     Winter Weather Advisory in effect until 5 PM MST this
      afternoon FOR ZONE 198.

&&

$$
weather.gov/billings