257
FXUS65 KRIW 120620
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1120 PM MST Thu Dec 11 2025

.KEY MESSAGES...

- Period of snow and gusty wind will bring slick roads to the
  Bighorns and Johnson County this morning.

- Above normal temperatures continue for most locations into
  next week.

- The next weather system moves in Tuesday or Wednesday with the
  next chance of snow and wind.

&&

.DISCUSSION...
Issued at 1117 PM MST Thu Dec 11 2025

The main concern in the short term will be the expected snow and
travel impacts across northern Wyoming, especially from the Big Horn
Range and eastward where the Winter Weather Advisory is in effect.
Snow is now spreading into the area and will continue through the
night before tapering off later in the morning. As was noted by
the day shift, the main concern will not be snowfall amounts,
as the should remain below advisory criteria. The main concern
is icy roads from the rapidly falling temperatures following the
warm temperatures today, (it was in the 50s and 60s) and a
possibly flash freeze. We will continue the advisory as is for
now. The only other location with greater than a 1 in 3 chance
of 3 inches or more is the northern Absarokas, and there are few
impacts in that location. Otherwise, the challenge will be
temperatures and how far south the front can reach. Johnson
County and the northern Bighorn Basin will be much cooler, with
the high in Buffalo possibly 40 degrees cooler than yesterday,
It will remain milder further south though as the front would
likely not make it. It should be a bit cooler than yesterday,
but still well above normal for mid December. We will continue
to have some gusty breezes at times as well with the jet close
to the area, but nothing like the wind we have seen the past few
days.

Zonal to flat ridging then controls the weather through the
weekend and into Monday. This means a continuation of above
normal temperatures and breezy conditions. It is possible we
could see more high temperatures records fall, especially on
Sunday and Monday following the brief cooldown on Friday and
Saturday. There will be a gusty wind continuing in the favored
areas, but high wind is not expected through that time period.
The only fly in the ointment through this period will be one
last piece of energy that could bring some snow showers to
Johnson County on Saturday but any amounts would be light and
impacts minimal to none.

The next likely weather maker in form of a Pacific trough and cold
front then approaches for Tuesday and Wednesday. Given the zonal
flow across the area, impacts look similar to this weeks situation
with most of the precipitation across western Wyoming with the
orographic enhancement. Models are split on if any precipitation
makes it East of the Divide though. There is higher confidence in
strong to potentially high wind, with most guidance having an 140 to
160 knot jet over Wyoming from later Tuesday through Thursday.
Details are obviously impossible to nail down this far out though.
We are highly confident on above normal temperatures continuing
across most of the area through most of the next seven days.
&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 930 PM MST Thu Dec 11 2025

VFR conditions expected throughout the entirety of the period at
all TAF sites. Light winds 10kts or less through Friday morning
remaining through much of the afternoon except for CPR/RKS
gusting up to 25-30kts after 18-20Z. Low chance (10-20%) of
light snow showers around COD the first couple of hours of the
period but confidence low carrying only VCSH at this point in
time. Otherwise, another shot of north of west winds to increase
after sunset around 00-01Z for COD/RIW as well as remaining
elevated at RKS gusting up to 18kts expected at these locations.
This should subside into the next TAF cycle with dry conditions
going forward through the weekend.

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

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 7 AM MST Friday for WYZ008>010.

&&

$$

DISCUSSION...Hattings
AVIATION...Lowe