713
FXUS65 KBYZ 130819
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
219 AM MDT Mon Oct 13 2025

.KEY MESSAGES...

- Frost/freeze for many areas this morning. Chilly morning for
  school bus stops.

- Light snow accumulations (1-2") may impact US-191 north of Big
  Timber to Judith Gap for this mornings commute.

- Increasing chance of precipitation Tuesday night through
  Thursday evening. Accumulating snow possible at higher
  elevations (above 7000ft).

- Turning mainly dry and warmer next weekend.

&&

.DISCUSSION...

Today through Tuesday night...

Chilly morning ahead as shallow easterly flow and cold air mass
have settled over our region. Readings will be in the mid 20s west
to mid 30s east for the morning rush. Dress the kids warm this
morning! We do have some light snow occurring over the Wheatland
County area since last evening, with an inch or two of
accumulation possible from near Melville to Judith gap. An inch
or two of accumulation is possible (50% chance of an inch)...and
may produce minor impacts (slick roads/limited visibility). Low-
mid level moisture lifts north/northwest today as 500 mb ridge
builds over the region, and with weakening upslope the light snow
will dwindle through mid morning. Look for a stratus cloud deck
over the western half of the CWA to gradually thin out through the
day. This will limit any warm-up for the many areas though, with
highs in the upper 30s and lower 40s west to lower 50s east.

In the meantime today out west, an upper low will drop down along
the coast. Southerly flow will strengthen in response from the
desert southwest into the Rockies. This will push some moisture
northward into our region. We could see a few light showers or
virga as early as late tonight and early tomorrow from this. The
upper low slowly starts to shift northeast into Nevada by Tuesday
afternoon. So look for a continued chance of isolated light
showers over our area (mainly western mountains) through Tuesday,
and increasing to a more scattered coverage by Tuesday night.
Temps will rebound a bit Tuesday ranging from around 50 west to
upper 50s east...even a few lower 60s possible in the southeast as
a warm tongue of air pushes north into that area.

Wednesday through Sunday...

Ensembles are in good agreement that upper flow will become
increasing divergent and moist over our region Wednesday as that
upper low drifts northeast from Nevada into the central Rockies.
Associated deformation zone slides into Montana adding additional
ascent across our region into Wednesday night. Widespread
precipitation is expected during this time with accumulating
snowfall possible over the high elevations. EC ensemble means are
more bullish for southern MT than the GEFs which takes the better
precip amounts further north. Cluster analysis seems to favor the
GEFs, but this could change. Overall, the probability of at least
a half inch of liquid is 40% over almost all the CWA with up to
70% in the high country. Look for temps to remain seasonably cool
through most of the week in the 40s and 50s. We may see unsettled
conditions yet Friday in an unstable NW flow before warmer and
drier conditions arrive this weekend. BT


.AVIATION...

09z Discussion...
Light RA/SN will continue in the mountains and foothills of south
central MT (KLVM) for the next few hours. Along with this precip,
expect widespread MVFR CIGs with localized IFR, especially in the
foothills (KLVM/KSHR). KSHR may also see some BR/FG in the early
morning hours which may reduce VIS to IFR as well and thus a TEMPO
line was added in their TAF. Winds will likely remain gusty (up
to 30kts) out of the east for a majority of the period near the
surface. Mountains will be obscured throughout the period. WMR
&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Tue     Wed     Thu     Fri     Sat     Sun
-------------------------------------------------------
BIL 044 032/051 037/052 041/052 040/059 037/057 039/065
    1/E 12/W    45/W    67/W    42/W    32/W    12/W
LVM 039 025/051 032/050 031/050 032/056 029/057 034/061
    1/E 13/W    67/W    76/W    43/W    42/W    13/W
HDN 050 031/053 035/055 040/053 036/061 034/057 034/066
    0/B 12/W    45/W    77/W    52/W    42/W    12/W
MLS 051 038/060 041/059 041/052 038/059 036/056 034/064
    0/U 01/B    35/W    66/W    43/W    22/W    11/U
4BQ 056 041/063 043/064 042/052 039/058 036/054 035/066
    0/U 11/B    33/W    65/W    42/W    22/W    11/U
BHK 052 036/057 038/057 040/055 035/057 032/055 031/064
    0/U 11/N    24/W    65/W    42/W    21/N    00/U
SHR 051 030/058 033/061 036/053 033/060 030/055 031/068
    0/B 11/B    34/W    77/W    53/W    43/W    11/U

&&

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

&&

$$
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