749
FXUS65 KBYZ 111041
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
341 AM MST Thu Dec 11 2025

.KEY MESSAGES...

- Strong southwest to west winds along the foothills west of
  Billings today. Gusts of 60 to 75 mph are expected from
  Livingston to Big Timber and Harlowton, while gusts of 50 to 60
  mph spread as far east as Rapelje and Molt.

- Cold front arrives late today, bringing a sharp drop in
  temperatures and rain changing to accumulating snow. A flash
  freeze with roads quickly turning icy may result in treacherous
  travel conditions late this afternoon and evening. Cold temps
  will persist through Saturday.

- Greatest snow accumulations tonight into Saturday are expected
  to be over the plains, generally from Harlowton to Billings and
  eastward towards Miles City and Broadus, where there is a 60 to
  80 percent chance of at least 6 inches of snow. Snowfall totals
  of 5 to 10 inches are anticipated.

- Warmer and drier weather expected to return by Sunday.

&&

.DISCUSSION...

Today through next Wednesday...

Big changes coming by this evening...BE READY. Have issued a
variety of winter highlights which begin later today. Please stay
in touch with the forecast for your area!

Strong downslope flow is yielding absurdly warm temperatures on
this night, with most of the west half of our cwa seeing 50s to
lower 60s as of 3am. Livingston`s all-time December record is 64F
and the current temp is a not-so-far-off 55F. The main story for
today is wind, of course, and we have been seeing frequent gusts
of 60-70 mph from Livingston to Big Timber and Melville, and near
Nye. Given the warm temps and well-mixed boundary layer at this
time, am concerned about strong winds pushing eastward somewhat
today, during the favored pre-frontal hours as 700mb winds are
still 50-60 knots. Have expanded the High Wind Warning to include
northern Stillwater and Golden Valley from 5am this morning to
5pm. High temps today will range from the 40s east to mid 50s to
lower 60s west...of perhaps mid 60s if there are any sun breaks.

Current surface analysis shows a Canadian cold front just north
of the MT/AB border. In fact, the fropa reached Lethbridge at
11pm. Climatological arctic frontal timing would place the front
to Billings by early afternoon, but models show it slowing as it
awaits a shortwave passage (currently moving from BC into AB).
Once the front reaches Cut Bank it is on average 10 hours from
Billings, so this will need to be monitored. The reason? Once the
fropa occurs we will see a rapid drop in temperatures, such that
rain changing to snow has a real risk of resulting in a flash
freeze and very icy travel conditions by this evening. Local
knowledge strongly suggests the post-frontal cooling will be
faster than guidance shows. At this time, fropa timing looks like:
Judith Gap and Miles City 1-3pm, Billings 3-5pm, Sheridan 4-6pm.
Expect sub-freezing temps within 2-3 hours of the fropa.

Eastern areas should see scattered rain showers today becoming snow
showers in the afternoon, while the west`s precip will hold off
til the front arrives. There should be a brief 1-3 hour window of
rain or mixed precip before the change to snow. The frontal push
will be followed quickly by overrunning snowfall per a very moist
Pacific flow. This initial period of overrunning will impact our
west to central parts through much of Friday before beginning to
shift to the northeast. By Friday evening, the west and south
should be finished while accumulation continues in the northeast
into Saturday. On Saturday, another shortwave passage should bring
another southwestward push of the cold air and in all likelihood
a little more precip. Then the event ends.

Ensemble QPF of 0.40-0.70" in the favored areas east of the
foothills would yield a good 6-10" snowfall with healthy snow
ratios achieved from a deepened DGZ. Areas near the foothills will
see the least snowfall, per the cold air being shallower and a
strong downslope component off the mountains. Temps during this
time will be much colder, mostly single digits and teens. In fact,
foothills locations at/above 5-6kft will be quite a bit warmer.
One thing to think about: once the main axis of snowfall shifts to
the northeast late Friday and Friday night, the shallow cold air
will remain east of the foothills, with mid level warming and
drying. It is plausible that we could see fog/freezing drizzle in
this environment, before the true downslope warming arrives (looks
like Saturday night). With abundant fresh snow cover we will
likely see some remarkable low level inversions Saturday night
into Sunday. When downslope winds surface the warmup will be
quick. There will also be a brief risk of blowing snow.

Sunday through next Thursday looks mostly mild and breezy, with
temps back to the 40s to mid 50s. This is the overwhelming ensemble
consensus. Models are starting to hint at a lowering of heights
and a Pacific wave by Wed/Thu. The Canadian cold air to our north
is extensive so once the zonal flow buckles along the Pacific
coast we will see another arctic blast. It`s only a matter of
time.

JKL

.AVIATION...

Strong winds along the western foothills will continue through
this afternoon (22Z) with winds gusting 50-70 kts (KLVM, K6S0,
K3HT). Rain east of Billings is expected to become more widespread
through the morning and early afternoon before a cold front
begins to change precipitation to snow around 21Z. Snow is
expected to continue across southeast Montana through Friday. MVFR
and IFR conditions will be common under snow bands with a 10-20%
chance for LIFR conditions. Torgerson

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Fri     Sat     Sun     Mon     Tue     Wed
-------------------------------------------------------
BIL 059 013/019 008/021 010/047 031/046 038/048 032/045
    7/W ++/S    43/S    00/B    00/B    01/B    33/W
LVM 059 020/035 028/040 033/053 035/052 037/050 033/046
    6/W 87/S    12/O    00/N    00/N    13/W    44/W
HDN 057 013/018 006/021 008/045 022/045 030/048 027/044
    6/W ++/S    74/S    00/B    00/B    01/B    34/W
MLS 046 005/009 902/012 001/040 023/040 029/045 026/040
    5/W 27/S    +4/S    00/B    00/B    01/B    22/W
4BQ 053 012/016 007/019 010/043 026/044 032/047 029/043
    5/W 48/S    85/S    00/U    00/U    01/B    22/W
BHK 043 902/005 907/009 903/041 023/043 029/045 023/040
    7/W 13/S    +4/S    00/U    00/B    00/B    22/W
SHR 060 015/027 010/031 018/054 026/052 032/052 027/047
    7/W 96/S    32/S    00/U    00/U    01/B    23/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Winter Storm Warning in effect from 2 PM this afternoon to 11
      PM MST Friday FOR ZONES 29-42-63-173-228.
     Winter Weather Advisory in effect from 5 PM this afternoon to
      5 AM MST Friday FOR ZONES 30>33-36-37.
     Winter Storm Watch in effect from late tonight through
      Saturday morning FOR ZONES 30>33-36-37.
     High Wind Warning in effect until 5 PM MST this afternoon FOR
      ZONES 34-42-63-65-66-141-172-228.
     Winter Storm Warning in effect from 5 PM this afternoon to 8
      PM MST Friday FOR ZONES 34-57-58-138-141-172-235.
     Winter Storm Warning in effect from 2 PM this afternoon to 8
      PM MST Friday FOR ZONE 68.
     Winter Weather Advisory in effect from 6 PM this evening to
      noon MST Friday FOR ZONES 169-170.
WY...Winter Weather Advisory in effect from 6 PM this evening to
      noon MST Friday FOR ZONE 199.

&&

$$
weather.gov/billings