287
FXUS65 KRIW 051745
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1045 AM MST Mon Jan 5 2026

.KEY MESSAGES...

- Snow will continue across western Wyoming today, especially
  before noon. After a lull this afternoon and evening,
  snowfall rates will increase again overnight across the
  mountains. Winter travel conditions can be expected over
  passes.

- Snow showers along I-80 could cause brief periods of reduced
  visibility through the morning.

- Mild and gusty along and east of the Divide today with occasional
  rain showers.

- Light to moderate snow will continue across western Wyoming
  through midweek. A cold front will arrive by late week
  bringing more seasonable temperatures to the area.

&&

.DISCUSSION...
Issued at 346 AM MST Mon Jan 5 2026

The active weather pattern will continue over the next few days,
especially west of the Continental Divide. The next in a series of
shortwaves is now pushing into western Wyoming, and will return
steadier snow rates in the mountains there through the afternoon.
Lower elevations across the west will see intermittent snow showers
with additional accumulations of an inch or two, mostly falling in
the morning. As has been the trend most of the season thus far, the
majority of travel impacts will be limited to the mountain passes
today. Light snow is also likely (60-80%) to impact the I-80
corridor through the day, with the best chances before noon. Impacts
are similarly expected to be limited here due to temperatures
peaking in the upper 30s. However, a stronger snow shower could
cause briefly reduced visibility to travelers today. Adding to this
will be wind that will develop by late morning as the surface
pressure gradient tightens across Wyoming. This will be most notable
from Sweetwater County through Natrona County as westerly gusts
reach 35 to 45 mph by mid afternoon before decreasing. Otherwise,
temperatures will again peak well-above normal east of the Divide,
nearing 50 degrees for most lower elevations. A few rain showers are
likely here, with the best chances (30-40%) across the Bighorn Basin
and into Johnson County.

A lull in snow is expected by late afternoon across western Wyoming
as the shortwave exits and moisture wanes. The next wave will
approach as midlevel flow shifts more northwesterly late this
evening. Accompanied by another moisture surge up the Snake River
Plain, this will return heavier snow rates to the mountains, mainly
across the Tetons and Yellowstone`s Pitchstone and Madison plateaus.
The heaviest snowfall rates are expected between midnight and
sunrise Tuesday when 6 to 12 inches can be expected. Another Winter
Weather Advisory may be needed to account for this, though the
heaviest snow is generally expected north of the higher-traveled
passes. Lighter but steady snow is then expected to persist across
the western mountains through Tuesday with mostly dry and mild
conditions continuing east of the Divide. Wind will ramp up for
Tuesday, however, with gusts of 40 to 55 mph for much of central
Wyoming.

The active northwest flow will persist through midweek, keeping
light to moderate snowfall going across the western mountains for
much of this period. Guidance is then favoring a longer wave trough
arriving by late week. This will bring widespread colder
temperatures to the area as a front pushes through Thursday, though
precipitation chances again appear to be mostly focused on the
western mountains.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1045 AM MST Mon Jan 5 2026

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

MVFR flight conditions are forecast at KJAC and KPNA through 21Z as
a weather system exits the region. After 21Z, all West of the Divide
terminals are expected to be VFR until the 10Z-12Z timeframe. A weak
disturbance aloft brings a period of snow showers to KJAC and MVFR
flight conditions to KJAC, KPNA, and KBPI. There is potential (15%
chance) of IFR ceilings moving into KPNA and KBPI after 05Z-07Z
Tuesday and these chances are reflected by a FEW004 or FEW010 group.

Expect elevated and gusty winds at KRKS much of the TAF period.
Winds remain around 12kts at KJAC before becoming gusty after
10Z as the previously mentioned disturbance moves across the
region. Mountain obscuration is expected much of the period at
KJAC, KPNA, and KBPI.

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

VFR flight conditions are anticipated the entire TAF period at all
East of the Divide terminals. There is a 10-20% chance of a snow
shower moving off the mountains around KCOD between 10Z-12Z Tuesday
as a weak weather system moves through. Given the low chances of a
shower at KCOD, there is no mention in TAF at this time.

KCOD and KCPR will be gusty most of the TAF period. Winds become
gusty late in the period at KRIW and KLND. Mountain wave activity is
most likely at KCOD between 02Z-09Z, with a gust of 50kts not
completely out of question.

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...
None.

&&

$$

DISCUSSION...Myers
AVIATION...Gerhardt