662
FXUS65 KBYZ 090928
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
228 AM MST Tue Dec 9 2025

.KEY MESSAGES...

- Very strong southwest to northwest winds across the region
  today. Gusts of 60 to 80 mph along the western foothills through
  midday, and gusts to 60 mph elsewhere after sunrise.

- Prolonged period of snowfall in the western mountains. Potential
  for multiple feet of snow through Wednesday, greatest on west
  aspects of the Beartooth Absarokas.

- A wintry mix of snow, rain and pockets of light freezing rain
  expected Wednesday, tracking from west to east.

- Above normal temps today to Thursday.

- Next shot of cold air is expected to arrive Thursday afternoon
  or evening. Cold front will bring a sharp drop in temperatures
  and be followed by accumulating snowfall. Travel conditions may
  become treacherous as wet roads freeze and turn icy.

- Periods of accumulating snow across lower elevations Thursday
  night into Saturday. Monitor the forecast for details!

&&

.DISCUSSION...

Through next Monday...

A very active week of weather is upon us...BE READY!

Already seeing gusts of 75 mph near Nye, 72 mph at Springdale, and
just recently an 82 mph gust at the Livingston airport. Lee side
pressures are falling at a rate of 1-1.5mb/hr as of 2am, and the
IDA-LWT gradient is up to 19mb. Mesoanalysis shows 700mb winds in
the west near 75 knots. Conditions remain on track for very strong
winds today, not just along the foothills but also across lower
elevations as a cold front arrives beginning around 15z. Thus,
peak gap flow should be in the 09-15z time frame, when gusts could
occasionally reach 80 mph. Other western foothills will see
periodic gusts of 65-75 mph from now thru midday. Lower elevations
will see strongest winds begin after sunrise. Surface temps have
risen to the 40s to lower 50s during the current night, and snow
cover has dwindled, so mixing won`t be an issue once cold
advection begins. A High Wind Warning remains in effect for most
of the region, and have added the Red Lodge Foothills and southern
Carbon as it looks like winds will veer enough to the NW to focus
strong gusts thru the gap between the Beartooths and Pryors
starting around late morning. HRRR runs have been consistent in
this regard.

As far as precip goes today, there will be light warm advection
rain from Rosebud County eastward early this morning. Temps in
this area are warm enough to eliminate any risk of freezing rain.
Through the course of the day we will see some light showers
coinciding with the mixed winds, mainly across the east and south.
And by the way, mountain snowfall will continue and will make no
changes to the winter highlights in effect through Wednesday
(another surge of moisture comes tomorrow).

Post-frontal air mass turns chillier tonight with lows below
freezing across the central and east. This is important as the
fast Pacific flow brings another moisture surge and a west-to-east
progressing area of warm frontal precip tomorrow. P-type is an
issue here. All indications are for a wet snow to rain transition,
with the possibility of a wintry mix (including freezing rain)
along the interface. Precip won`t be particularly heavy, with snow
accumulation up to an inch in the east, but the risk of freezing
precip will need to be watched, especially east of Billings as
downslope warming kicks back in over the west.

Speaking of downslope warming, it looks like another period of
strong winds along the western foothills Wednesday into Thursday.
There is a 90% chance of 50+ mph gusts and 60% chance of 60 mph
gusts at the gap locations, with the peak likely to occur
Wednesday night and early Thursday. Non-gap areas have a 60%
chance of seeing gusts reach 50 mph.

All of the downslope flow and above normal heights will keep our
temps quite a bit warmer than normal. Look for highs generally in
the 40s to mid 50s today, tomorrow and even Thursday (depending on
cold front`s arrival time). In fact, there are increasing odds
for high temps near 60F on Thursday (30% chance) as models have
trended slower with the fropa time, which looks to be in the
afternoon to early evening.

Thursday deserves more attention and is looking more and more
like a high impact day. The aforementioned Canadian front will
bring a very sharp drop in temps, and will be followed quickly by
overrunning snow per the impressive Pacific moisture fetch. As a
result, this is a strong candidate for a flash freeze and quick
onset of treacherous travel conditions for the evening commute.
We could see temps near 60F followed by teens after sunset, with
snow accumulation on top of very icy roads. Plan accordingly for
Thursday!

Periods of overrunning snowfall and much colder temps are in store
Thursday night to Saturday, with what looks like a couple
shortwaves cresting a broad Pacific NW ridge. Temperature profile
should favor a deep DGZ so snow ratios will be healthy. WNW mid
level winds means a downslope component and shallower cold air along
the western foothills, so heaviest snowfall should occur east of
the foothills, and quite possibly east of Billings. This remains
very much to be seen as small deviations will alter the location
of heaviest snow. All told, there is a high chance of 4+ inches
over a 48-hr period, and in fact a 50-75% chance of 6+ inches,
greatest near places like Hysham, Colstrip, Hardin and Lame Deer.
The odds of 6+ inches at Billings is 50%. When all is said and
done, we are likely looking at an area of 6-12" of snow in a NW to
SE oriented area through central to eastern parts of our forecast
area. This will coincide with temps in the single digits and
teens. It will be warmer in the mountains as this air mass looks
to remain only along the eastern slopes.

All indications are for cold air to remain in place through
Saturday, then lee side troffing commences again promoting dry,
windy and warmer conditions for early next week. Something to
think about eventually is a risk of blowing/drifting snow as the
arctic air retreats. Consensus among ensembles is for a stretch of
warm weather next week with Pacific flow dominating.

JKL

.AVIATION...

Strong winds continue this morning over the western foothills and
gap areas, including KLVM, with southwest to west gusts in the
50s and 60s kts. For all other TAF sites, westerly gusts of 40-50
kts will be common by late morning. Winds will gradually decrease
from west to east this afternoon through evening. Isolated to
scattered showers will end late this afternoon before scattered to
numerous snow showers spread west to east Wednesday morning.
Mountains will be obscured through the TAF period due to heavy
snowfall. Archer

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Wed     Thu     Fri     Sat     Sun     Mon
-------------------------------------------------------
BIL 052 031/052 041/054 008/016 007/019 009/041 024/042
    4/W 37/O    36/W    88/S    52/S    10/B    00/B
LVM 051 033/053 045/055 019/039 022/040 029/048 033/049
    4/W 87/O    35/W    76/O    32/O    11/B    11/B
HDN 051 027/049 037/053 006/016 004/019 003/036 017/040
    6/W 29/O    67/W    98/S    63/S    11/B    10/B
MLS 047 024/040 031/039 000/007 905/009 902/031 016/034
    5/W 08/O    66/W    66/S    72/S    10/B    10/B
4BQ 050 027/043 034/046 005/014 004/017 005/036 020/037
    4/W 08/O    75/W    87/S    62/S    10/B    00/B
BHK 046 017/036 025/037 905/005 908/008 905/030 015/035
    7/W 06/S    65/W    54/S    72/S    10/B    10/B
SHR 051 024/048 034/055 009/028 009/028 014/046 022/046
    5/W 27/S    53/W    75/S    32/S    00/B    00/B

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...High Wind Warning in effect until 5 PM MST this afternoon FOR
      ZONES
      29>34-36-37-42-57-58-63-138-141-169-170-172-173-228-235.
     High Wind Warning in effect from 8 AM this morning to 5 PM
      MST this afternoon FOR ZONES 56-139.
     High Wind Warning in effect until 11 AM MST this morning FOR
      ZONES 65>68.
     Winter Storm Warning in effect until 5 PM MST Wednesday FOR
      ZONE 67.
WY...High Wind Warning in effect until 5 PM MST this afternoon FOR
      ZONE 199.
     Winter Weather Advisory in effect until 5 PM MST Wednesday
      FOR ZONE 198.

&&

$$
weather.gov/billings