873
FXUS65 KRIW 231003
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
303 AM MST Sun Nov 23 2025

.KEY MESSAGES...

- Skies will remain mostly clear this morning. The only areas
  with low clouds will be far southwest WY around Cokeville and
  across portions of Yellowstone National Park.

- Temperatures will remain around 5 to 10 degrees warmer than
  normal today, likely being the warmest day for the next seven
  days.

- A strong cold front will push through Monday afternoon into
  Monday night with increasing precipitation chances for the
  northern half of the area. Lows will drop into the teens and
  single digits Monday and Tuesday night.

- The weather pattern will remain active this week, but little
  impacts are expected until next weekend when there is likely
  (60%) to be a large winter weather system.

&&

.SYNOPSIS...
Issued at 1240 AM MST Sun Nov 23 2025

Quiet conditions continue today, before a strong winter storm
moves over the area Monday. This system will lack any moisture
for any widespread precipitation, but western portions and the
northern mountains continue to be the locations with the best
chances for snow (both mountain and valley locations). Winds
will increase Monday morning ahead of the front, with gusty
winds occurring across the forecast area through the afternoon
and evening. The cold front will usher in the first real taste
of winter, with highs on Tuesday remaining in the 30s for much
of the area. Northwest flow aloft will keep conditions a bit
breezy through the middle of the week, before another winter
storm potentially impacts the region next weekend.

&&

.DISCUSSION...
Issued at 1240 AM MST Sat Nov 22 2025

Another quiet day across the Cowboy State today, with isolated
areas of fog over portions of Yellowstone NP and the Bear Valley
in far southwestern Lincoln County. These conditions are not
expected to linger as long as they did Saturday and should lift
out by 18Z. Winds will generally be light again today, except
across portions of Natrona County where gusts around 25 mph will
continue. These gusts will subside by 18Z. Daytime temperatures
will be slightly warmer and make it the warmest day of the
upcoming week. Enjoy these conditions because winter will
finally come knocking Monday.

A storm system will move onshore over the PACNW Sunday night,
continuing toward the Northern Rockies Monday morning. 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 before sunrise Monday
morning. This trend will continue through the morning hours and
become more widespread. Westerly winds of 30 to 45 mph will be
common across areas west of the Divide by midday, as well as
portions of Natrona County. Locations like Cody and Dubois will
also be included, with the higher winds occurring at Dubois.
These winds will continue to spread across areas east of the
Divide through the afternoon, as the front begins to move over
northern portions. Winds will then turn northwesterly in the
wake of the front, continuing to gust 25 to 40 mph through much
of the night Monday night. Locally higher gusts around 45 mph
will occur over northern Johnson County. Winds will continue to
decrease from west to east Tuesday morning, possibly lingering
over portions of Johnson and Natrona counties through the
afternoon. As mentioned in previous discussions, any
precipitation will be very limited due to a lack of available
moisture. This will be due to a closed low currently over the
Four Corners that will be exiting over the Central Plains ahead
of this incoming system. Precipitation chances over western
portions will be limited Monday morning, with only a dusting of
snow expected. Chances will increase through the afternoon and
expected to stay as snow in the Jackson Valley, 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. 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. 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. A dusting
of snow, less than 1 inch, is also expected across portions of
Johnson and Natrona counties Monday night as the cold front
rushes through. Due to the timing of the front, temperatures
will only be about 5 to 10 degrees cooler with readings in the
40s to lower 50s. Western portions will be on the colder side of
that range.

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, as a broad ridge develops over the
PACNW. This will keep conditions breezy across southern portions
and Johnson and Natrona counties. 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.

There could be a minor shortwave moving over the area Friday,
ahead of the main storm system. This would bring chances for
snow over mainly northern portions. Model solutions remain in
flux for the next winter storm next weekend. This system looks
to be much stronger than Monday`s storm, with better chances for
widespread snow and colder temperatures.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 302 AM MST Sun Nov 23 2025

VFR conditions are expected through 12Z Monday at all TAF sites.
Areas of high level clouds will pass by from time to time, but
no lower ceilings are expected. Wind will be generally 10 knots
or less expect in vicinity of KCPR where gusts to 18 knots are
possible through the day. Ceilings may lower after 09Z at KJAC
as a weak weather system approaches from the northwest but any
showers should hold off until after 12Z.
&&

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

&&

$$

SYNOPSIS...LaVoie
DISCUSSION...LaVoie
AVIATION...Hattings