835
FXUS65 KRIW 241017
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
317 AM MST Mon Nov 24 2025

.KEY MESSAGES...

- A strong cold front today brings gusty west winds, colder
  temperatures, and precipitation chances across the northern
  half of the area. Minor winter travel conditions are possible
  for Teton and Togwotee Passes through the day and into the
  evening.

- Multiple weak weather systems this week bring light snow over
  western Wyoming, with little to no impacts expected.

- A larger winter storm system will impact the region this
  weekend, which could bring the first widespread lower
  elevation snow of the season. Lots of uncertainty continues
  at this time.

&&

.DISCUSSION...
Issued at 1252 AM MST Mon Nov 24 2025

The next storm system is currently moving over the PACNW and
will reach the Cowboy State later this afternoon. The main
factor with this system will be the winds, so we will discuss
this first. The associated cold front will reach far
northwestern portions between 18Z and 00Z. The sfc pressure
gradient will tighten in response to the approaching front, with
gusts increasing to 20 to 35 mph over northwestern portions
between 12Z and 15Z (5am and 8am) this morning. This trend will
continue through the morning hours and become more widespread
across areas west of the Divide. Westerly winds of 30 to 45 mph
will be common west of the Divide by midday, as well as portions
of Natrona County, the Upper Wind River Basin and the Cody
Foothills. These winds will continue to spread across areas east
of the Divide through the afternoon, as the front begins to
move over northern portions. Stronger gusts of 60 to 70 mph will
occur by midday over the east slopes of the Absaroka and Wind
River Mountains, continuing through the afternoon and gradually
decreasing in the evening behind the front. Winds will then turn
northwesterly in the wake of the front, continuing to gust 25
to 40 mph through much of the night tonight. Higher gusts of 45
to 55 mph will occur over northern Johnson County late
tonight/early Tuesday morning. An isolated gust over 60 mph
cannot be ruled out. Winds will continue to decrease from west
to east Tuesday morning, lingering over portions of Johnson and
Natrona counties through the rest of the morning. Gusts of 40 to
45 mph will continue over northern Johnson County by sunrise
Tuesday morning, decreasing to 25 mph by midday. As mentioned in
previous discussions, any precipitation will be very limited
due to a lack of available moisture. Precipitation chances over
northwestern portions will be limited this morning, and be
mainly confined to portions of Yellowstone NP and the Tetons.
Chances will increase and be more widespread over the western
mountains after 18Z. Any precipitation in the lower elevations
is expected to stay as snow, despite expected afternoon
temperatures in the upper 30s. This will be due to 700mb
temperatures around -6C (which puts snow levels around 5500ft).
These warmer temperatures will obviously limit any accumulation
and will likely stay in grassy areas. Forecasted snowfall
amounts remain in the 1 to 3 inch range in the northwestern
mountains, and a half inch to 1 inch in the Jackson Valley.
Locally higher amounts up to 5 inches is expected in the
Tetons. Precipitation chances will increase over northern
portions toward the latter half of the afternoon, as the cold
front begins to drop southward. 1 to 3 inches are also expected
over the Bighorns, with the higher end of this range occurring
on the northern end of the mountains. Rain will change to
rain/snow mix over portions of Johnson County after sunset, as
the cold front moves through the area. Due to the timing of the
front, temperatures will only be about 5 to 10 degrees cooler
today with readings in the 40s to lower 50s. Western portions
will be on the colder side of that range.

Lows tonight will range from the single digits to lower teens,
with the western valleys and Upper Green River Basin being the
colder locations. Highs on Tuesday will be 10 to 20 degrees
colder, with readings in the 30s for most locations. Northwest
flow aloft will be in place over the Cowboy State in the wake of
today`s cold front, as a broad ridge develops over the PACNW.
Temperatures will moderate back to seasonal normals by
Wednesday, and readings slightly above normal over southern
portions on Thanksgiving Day. Gusty winds of 25 to 30 mph will
also occur over the Wind Corridor (Rock Springs to Casper) on
these days. This pattern will also allow for embedded shortwaves
to bring chances for snow over the western mountains Wednesday
and Thanksgiving Day. Temperatures will moderate slightly
Wednesday, but return to more seasonal readings for Thanksgiving
Day. Little to no travel impacts are expected Wednesday and
Thursday.

A minor shortwave on Friday could bring chances for snow over
northern portions, ahead of the developing storm system this
weekend. Model solutions remain in flux for this storm, mainly
due to its strength and coverage (this storm will likely impact
much of the Intermountain West). This system will be much
stronger than today`s storm, with better chances for widespread
snow and colder temperatures.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 311 AM MST Mon Nov 24 2025

A weather system will move in from the west and bring some
impacts mainly to the northern and western terminals. Main
impacts initially will be at KJAC, with MVFR conditions most of
the day with low ceilings and -SN. Some tempo snow possible as
early as 12Z, but main influence will be in the 23/16Z to
24/00Z timeframe, with improvements through the evening. The
trailing front then sweeps across areas east of the Divide
between 24/00Z and 24/06Z, bringing a wind shift from the
northwest with gusts 25 to 30kts. A brief rain/snow squall is
possible at KCOD/KWRL as the front passes. With a slight shift
south we also added some PROB30 groups to KBPI and KPNA as the
front sweeps across that area as well.

Otherwise the main aviation impact for remaining sites will be
the gusty west to southwest winds during the day, with frequent
gusts of 25 to 35 knots, which are expected to continue into
the Monday evening with some decrease in wind after 08Z Tuesday
from west to east.

Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for
the latest information on smoke, icing, and turbulence
forecasts.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...LaVoie
AVIATION...Hattings