059
FXUS65 KBYZ 172015
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
115 PM MST Mon Nov 17 2025

.KEY MESSAGES...

- Near to above normal temperatures (45-60 degrees) continue
  through the weekend.

- Low (10 to 30%) chances for precipitation (mainly rain) through
  Wednesday, higher chances (30 to 60%) over the mountains (snow).

- Windy conditions are possible in the Livingston/Big
  Timber/Harlowton vicinity Friday night into the weekend.

&&

.DISCUSSION...

This afternoon through Monday...

Unremarkable weather forecast continues this week as a split in
the jet stream pushes weather systems mainly north and south of
the area, a few just grazing our part of the northern Rockies at
times. The only real noteworthy weather element is the persistent
near to above normal temperatures through the forecast, and the
lack of significant snowfall particularly in the mountains.

A broad trof is over the western U.S. this afternoon with 3
distinct meso-circulations embedded within it. The closest one is
moving across Wyoming just north of the Colorado border, wrapping
moisture around the east side and up into far SE Montana. Webcams
show wet roads in the Alzada area and Baker has seen a few periods
of light rain so far today, both with temperatures in the mid 30s.
Soundings in this area show temperatures are warmer above the
surface so not expecting any mixed precipitation this afternoon in
these areas, and precipitation there should end over the next
several hours as the disturbance continues to move out into the
plains.

A few weak impulses will move into western zones this evening and
slowly move east tonight through the day Tuesday. Models are
showing a few areas of light precipitation associated with this
energy, though precipitation chances remain in the 10 to 20
percent range outside of the mountains. May turn out to be little
more than sprinkles at times over the lower elevations.

A northern stream low moves along the Canadian border Tuesday
night and shifts east of the area Wednesday bringing shortwave
ridging and stronger downslope flow to the area for a dry day on
Wednesday for central and eastern zones. Pacific moisture will
persist over the western mountains and foothills for continued
low (20 to 40%) precipitation chances there, and this may be
overdone a bit for our area given the split flow ridging over the
area. In any event any precipitation will be very light, even in
the mountains.

Energy continues to flow south and north of the area Thursday
through Saturday with west to east oriented ridging aloft over the
area. This will keep conditions dry, even in the higher terrain.
By late Friday will see westerly winds aloft increase which will
force surface winds along the western foothills to increase. Gap
winds will pick up Friday night through Saturday morning at least
and may need a wind advisory for the usual gap wind areas. At this
point the US-191 corridor looks windy but not enough for
highlites. Will keep tabs on this through the week.

For the end of the weekend heading into Thanksgiving week the
forecast has become significantly more uncertain. The latest
deterministic GFS has deviated to a strong zonal pattern with
downslope winds keeping dry and warm conditions going, while the
Canadian is continuing to show a cold snowy forecast for the
holiday week starting early Monday. The ECMWF is leaning toward
the Canadian but does show a shift of the colder air a bit further
north and delays it a bit. Given this change will have to wait a
bit to see the ensembles and how they shake out. This could be
just a deterministic wiggle in the forecast that the ensemble
trends don`t go toward, but definitely a big deviation to warmer
and drier in the GFS deterministic this morning. Stay tuned
through the week if you have travel plans for the Thanksgiving
holiday. Chambers

.AVIATION...

Expect occasional mountain obscuration due to isolated showers and
low clouds over the mountains to continue through the TAF period.
Patchy fog is possible near all TAF sites (20% chance) tonight
into Tuesday morning. Archer

&&

.PRELIMINARY POINT TEMP/POPS...

    Tue     Wed     Thu     Fri     Sat     Sun     Mon
-----------------------------------------------------------
BIL 041/058 036/052 030/052 030/053 034/054 033/051 032/046
    22/R    12/R    10/U    00/U    00/N    12/R    23/O
LVM 035/056 034/051 030/053 030/052 032/051 032/049 031/048
    22/R    13/R    10/U    00/N    11/N    22/O    33/O
HDN 037/057 034/052 027/052 026/052 030/054 030/051 028/049
    22/R    11/B    20/U    00/U    01/B    12/R    23/O
MLS 032/055 035/051 027/049 028/052 031/051 030/050 027/046
    12/R    31/B    10/U    00/U    00/B    11/B    12/O
4BQ 034/055 036/052 029/049 030/052 032/051 031/049 029/046
    12/R    21/B    10/U    00/U    00/B    11/B    12/O
BHK 029/053 034/051 025/047 026/051 029/049 027/047 024/044
    12/B    21/B    10/U    00/U    00/N    11/B    01/B
SHR 035/055 030/053 026/052 025/052 027/052 027/050 025/048
    23/R    11/B    20/U    00/U    00/B    12/R    22/R

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.

&&

$$
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