190
FXUS65 KBYZ 052112
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
212 PM MST Fri Dec 5 2025

.KEY MESSAGES...

- Light mixed wintry precipitation tonight into Saturday morning.
  Rain/Snow/Freezing Rain/Sleet are all possible, with a mix of
  Rain/Snow most likely.

- Periods of moderate to heavy snow, strong winds, and whiteout
  conditions for area mountain through the Saturday afternoon.
  Heaviest snow on west to northwest aspects.

- Gusty to locally strong wind gusts tonight into Saturday morning
  for the western foothills, including Red Lodge, Livingston, Nye,
  Big Timber, Harlowton.

- Warmer and drier pattern Sunday into early next week.
  Temperatures in the 50s forecast for many areas Friday.

- Uncertainty increasing for mid to late next week.

&&

.DISCUSSION...

Through next Thursday...

Highlites, no changes to winter weather highlites that were
updated this morning. Issued a wind advisory for tonight through
Saturday morning for the Livingston vicinity.

Interesting and complex forecast for the next 24 hours for our
area. We are currently sitting in between warmer air to the west
and a persistent cold trof to the east which puts the jet stream
over our area at times. Tonight into tomorrow is one of those
times with a strong 120-140kt jet nosing over the area this
evening and then shifting southward tomorrow, opening the door to
cooler air to slide in from the northeast Saturday afternoon.
Pacific moisture riding the jet over the area will over-run the
colder surface air brining widespread light precipitation to the
lower elevations tonight into tomorrow, though precipitation will
be fighting increasing downslope winds through the night. The
downslope winds will actually warm temperatures overnight which
will bring a wintry mix of rain/snow and possibly light freezing
rain/sleet overnight into early Saturday morning. For those
traveling tonight, be alert for this mixed precipitation as rain
falling at temperatures just above freezing may freeze on cold
surfaces including roads. At this time precipitation looks light
enough to hold off on an advisory for the mixed wintry
precipitation but will have to monitor how conditions evolve
closely tonight. As the jet shifts southward cooler air will
spread southwest into the area and precipitation will turn back
over to light snow. Latest probabilities for more than two inches
of snow tonight into Sunday have dropped into the 20 to 35
percent across northeast zones with the latest model runs, so will
hold off on advisory for snow for Custer/Fallon/Carter county and
advertise 1 to 2 inches of accumulation from a couple of waves of
snow over the next 48 hours.

Winds look stronger than previous forecast runs for the western
foothills tonight as the jet stream works over the area. Soundings
and guidance show a hybrid mountain wave/gap wind setup for
Livingston with NBM numerical guidance showing some of the
strongest wind gusts I`ve seen in that product (45-49kts). Though
other guidance is weaker, the pattern and bufkit soundings along
with the NBM numerical guidance is enough to support an advisory
for tonight in the Livingston area. Held off adding the Beartooth
foothills due to the jet orientation being perpendicular to the
valleys there which should keep wind speeds below advisory
criteria there. That said it will be a breezy to gusty night along
the foothills, even into Red Lodge with gusts in the 25 to 40 mph
range expected. Sheridan foothills could get into some gustier
conditions before sunrise as winds work down the east slopes of
the Bighorns. As the westerly gusts develop expect some big
temperature swings for the foothills.

Winter highlites for the mountains look good and no changes
planned at this time. Addition of strong winds and near whiteout
conditions will make travel/activities in the high country
difficult (Bighorn Mountains) to Dangerous
(Beartooth/Absaroka/Crazy mountains) tonight into tomorrow. Snow
accumulations near a foot expected for the western mountains and
around 6 inches for the Bighorn/Pryors with locally heavier on
west/northwest facing slopes.

Bottom line is tonight into tomorrow will be an active weather
period with temperature swings at odd times, gusty to locally
strong winds in spots, and potential for mixed precipitation.

Cooler air and areas of light snow late Saturday into Saturday
night will shift back out of the forecast area Sunday as a
building Pacific ridge nudges into the area. Temperatures Monday
will climb above seasonal normals for most locations Monday
afternoon and could see highs get into the 50s central and west on
Tuesday.

From Tuesday going forward next week the upper ridge looks like it
will at the very least flatten out which will take the edge off of
temperatures. The NBM is also grabbing onto a wetter Pacific flow
during this period advertising general 20 to 50% precipitation
chances through this period. Uncertainty is high for this period
so stay tuned to see whether this moist flow will be a persistent rain
or snow producer in the lower elevations as there are hints that
much colder Canadian air may slosh down the front range toward the
later portion of the week. Chambers

.AVIATION...

18z Discussion...

Isolated snow showers linger across the region at this hour.
Precipitation is expected to fill back in from west to east around
00z. Expect a wintry mix of all precipitation types at terminals
away from mountains (Including KBIL). This scatted mixed
precipitation is expected to linger through most of the period.
Expect widespread MVFR CIGs and VIS with sporadic dips down to
IFR. In any of the heavier snow showers (most likely at KSHR and
KLVM) IFR VIS should be expected.

In eastern Montana (KMLS/KBHK) low clouds continue to blanket the
region and this will be the theme for the entire period,
including through the precipitation. After 12z the precipitation
will start to thin out in this region which will allow
fog/freezing fog to rapidly develop upon the end of the
precipitation. The period between 12z and 18z near KMLS/KBHK will
likely see rapid continuous fluctuations between MVFR RASN and
LIFR FZFG.

Gusty winds will also be a concern for much of the forecast area
after 09z. WSW winds at KBIL may gust as hig has 25kts after 12z.
Winds in the foothills (KLVM/K6S0) may be able to touch 40kts
during this timeframe. This may allow for even further VIS
reductions under snow showers due to BLSN. Expect mountains to
partially to fully obscured for the entire period. WMR

&&

.PRELIMINARY POINT TEMP/POPS...

    Sat     Sun     Mon     Tue     Wed     Thu     Fri
-----------------------------------------------------------
BIL 028/038 022/042 030/044 034/050 032/046 027/039 019/029
    84/O    10/B    00/B    14/R    55/O    55/O    44/S
LVM 030/039 027/041 030/044 034/049 032/049 031/043 023/043
    97/S    30/N    20/N    24/R    66/R    55/R    43/R
HDN 023/037 018/042 025/044 030/049 027/044 022/038 015/028
    96/O    41/B    10/B    15/R    56/R    56/O    44/O
MLS 018/026 011/035 022/039 031/046 024/036 017/029 009/021
    77/S    41/B    00/B    23/R    34/O    53/O    33/S
4BQ 022/034 016/040 024/043 030/048 027/040 022/037 016/026
    64/O    21/B    00/B    13/R    43/O    43/O    33/S
BHK 013/027 004/033 017/039 025/043 017/033 012/029 006/020
    78/S    52/S    00/B    34/R    33/S    62/O    32/S
SHR 019/039 018/042 021/046 026/052 025/046 022/041 014/034
    65/O    31/B    00/B    03/R    54/O    55/O    43/O

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Wind Advisory in effect from 6 PM this evening to noon MST
      Saturday FOR ZONE 65.
     Winter Storm Warning in effect until 2 PM MST Saturday FOR
      ZONES 67-68.
     Winter Weather Advisory in effect until 2 PM MST Saturday FOR
      ZONE 171.
WY...Winter Weather Advisory in effect until 2 PM MST Saturday FOR
      ZONE 198.

&&

$$
weather.gov/billings