721
FXUS65 KRIW 300455
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
955 PM MST Sat Nov 29 2025

.KEY MESSAGES...

- A weak weather system brings light snow to western and
  southern Wyoming Sunday. The heaviest snow falls between 9 AM
  and 3 PM and produces amounts of one inch or less. Isolated
  areas in Sweetwater County could see up to 2 inches, while
  south Lincoln County may see 2 to 3 inches.

- A clearing sky Sunday night allows for single digit lows for
  most lower elevation locations. Seasonal average overnight
  lows range from the lower to mid teens.

- Multiple weak weather systems are expected through the coming
  week, bringing light snow chances and keeping temperatures
  cool to seasonal. The best chance for widespread light snow
  appears to come Tuesday and Tuesday night.

&&

.UPDATE...
Issued at 1108 AM MST Sat Nov 29 2025

With snow moving out of the area, the rest of today remains dry.
Current satellite shows most of the area in white, though southwest
Wyoming remains brown (no snow). This should change tomorrow as a
weak system brings snow chances across western and southern Wyoming.
Latest models have west of Divide locations generally seeing an inch
or less, with isolated areas closer to 1.5 inches where heavier snow
showers occur. Highest totals are expected over the Salt/Wyoming
Ranges (2 to 4 inches) and into the lower elevations of southern
Lincoln County (1 to 3 inches). Isolated areas close to 4 inches
could also occur (20 percent chances).

Sunday afternoon, some gusty north-northeast winds, 25 to 30 mph,
occur over I-80. With snow chances, this could cause some minor
winter travel conditions through the evening.

&&

.DISCUSSION...
Issued at 217 AM MST Sat Nov 29 2025

Winter has finally arrived and punched many locations in the mouth
Friday night. It was rather nasty when I arrived for my shift;
snow with wind gusts close to 50 mph. As I write this before 2
am, snow is still ongoing across portions of the area, mainly
the eastern portions. We should see the worst of this through
around 3 am, with improving conditions following that as the
front continues to move south away from the area. All snow
should be over by sunrise, if not before. As for wind, it
continues to be quite strong, especially in the northwest flow
locations. Buffalo and Greybull are continuing to have gusts to
around 50 mph, although they are decreasing elsewhere. We may
be able to cancel the Advisories somewhat early, if the wind
decreases a bit earlier than expected.

The main story today will be the cold temperatures, the coldest so
far this season. This will especially be the case in areas that saw
some accumulating snow, adding the assist from the fresh snow
increasing the albedo and the weak late November sun having a
limited effect. Most locations will stay in the 20s and some
areas in the teens. Tonight will be the coldest night of the
season for many, especially east of the Divide where most areas
have at least a 1 in 2 chance of lows falling into the single
digits. Increasing high clouds late tonight should keep most
locations above zero though.

The aforementioned clouds will be coming from the next wave that
will largely impact southern and southwestern Wyoming, as it
drops in from Idaho. This wave is also a fast mover and has
even less moisture to work with than last nights wave, and the
best dynamics remain to the south and west of Wyoming.
Probabilistic guidance shows even less snow than yesterday. The
only location with a greater than 1 in 2 chance of 2 inches or
more are the Salt and Wyoming Ranges, with only a 1 in 4 chance
of 4 inches. The lower elevations from Afton through Rock
Springs have around 1 in 3 chance of an inch or so of snow. As
for east of the Divide, a few showers may jump the Divide, but
any amounts should minuscule. All snow from this system should
end by midnight Sunday night.

Transitory ridging should bring a dry and somewhat warmer day for
Monday. The next system then drops in on our fast moving northwest
flow for Monday night and Tuesday. There continues to be some model
disagreement on the details of the system, but there is greater than
a 1 in 2 chance of some locations getting some snow from this
system, although probabilistic guidance also shows there is less
than a 1 in 4 chance anywhere in the lower elevations of 3
inches or more, so right now it is not looking like a major
storm. Another wave may approach for the end of the week, but
details are impossible to determine this far out. Temperatures
look to moderate to near normal to slightly below normal
through much of next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 955 PM MST Sat Nov 29 2025

West of the Continental Divide...KJAC/KRKS/KPNA/KBPI Terminals

A quick-moving shortwave will rotate across southwest Wyoming with
the greatest impacts during the day Sunday. VFR conditions begin to
deteriorate between 13Z-16Z/Sunday with IFR/MVFR developing around
16Z at KBPI/KPNA and 18Z at KRKS. The north end of this wave wraps
around to the vicinity of KJAC. Current trends keep MVFR to the
south of KJAC, so only have PROB30 low-end VFR from 15Z-19Z/
Sunday. Conditions slowly improve from north-to-south between
21Z-24Z/Sunday as the wave rotates out of the region. VFR follows
at all terminals, although the Sunday night potential for fog
will need to be monitored at KBPI/KPNA. Mountains frequently
obscured 15Z-23Z/Sunday, with mountain top obscurations
throughout the period.

East of the Continental Divide...KCPR/KCOD/KRIW/KLND/KWRL Terminals

Impacts from a quick-hitting shortwave moving through southwest
Wyoming will be limited to lower-end VFR ceilings in the central
basins during the midday hours Sunday. There could be a few snow
showers spill over the Divide near KLND early Sunday afternoon, but
the chance is at best 30 percent. Opted to leave out PROB30 for the
time being. Otherwise, VFR conditions reign through the period.
Cloud cover dissipates from north-to-south from late Sunday
afternoon into the evening hours. Mountain top obscurations occur
along the Continental Divide between 12Z/Sunday and 03Z/Monday.

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

&&

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

&&

$$

UPDATE...Wittmann
DISCUSSION...Hattings
AVIATION...CNJ