298
FXUS65 KRIW 242247
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
347 PM MST Mon Nov 24 2025

.KEY MESSAGES...

- A 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 into this evening.

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

- A larger winter storm system impacts the region this weekend,
  bringing much cooler temperatures and the potential for the
  first widespread lower elevation snow of the season. Lots of
  uncertainty continues at this time.

&&

.UPDATE...
Issued at 1126 AM MST Mon Nov 24 2025

Overall messaging over the next 24 hours remains unchanged - gusty
west winds today with mountain snow. The main push of the cold front
is still expected to push through late today and into tonight,
bringing a quick shot of heavier snow showers to the west.
Combined with wind, this could bring some minor winter travel
conditions to Teton and Togwotee Pass. See discussion below for
full details on today`s weather system.

&&

.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 /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 347 PM MST Mon Nov 24 2025

A passing shortwave and associated cold front will be the main story
over the next 12 hours. The cold front continues to move into the
northern part of the state to start the period, sliding southward
across northern and central WY through 04Z this evening. With the
front, expect winds to turn to the north and remain gusty after the
frontal passage particularly for KCOD, KWRL, and KRIW. A few gusts
of 40 to 50kts have been observed across the northern part of the
Bighorn Basin with the frontal passage and will remain possible
through around 04Z this evening.

Snow showers are also possible with the front, with most likely
chances at KJAC (60% chance), KCOD (30% chance) and KCPR and KWRL
(20% chance). Brief MVFR conditions are possible with the snow
showers behind the front, but should not last for more than 1 to 2
hours if they do occur.

After 09Z, winds decrease and skies quickly clear, with most
locations seeing SKC and winds less than 6kts by 12Z Tuesday. These
quiet conditions will continue through the rest of the period.

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.

&&

$$

UPDATE...Wittmann
DISCUSSION...LaVoie
AVIATION...Hensley