394
FXUS65 KRIW 171016
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
416 AM MDT Fri Oct 17 2025

.KEY MESSAGES...

- Gusty west winds are expected today for much of the area.
  Otherwise, warmer and drier through sunset.

- Showers will return to northern Wyoming this evening as the
  next system arrives. This will bring light rain and mountain
  snow showers to areas along and east of the Continental Divide
  through Saturday morning.

- Unsettled conditions continue on Sunday as another system
  arrives. Widespread gusty to strong winds are possible
  through the day, with rain and mountain snow showers expected
  Sunday afternoon through Monday morning.

&&

.DISCUSSION...
Issued at 354 AM MDT Fri Oct 17 2025

With the previous system now well off to our northeast, Friday will
be dry and mild as temperatures return to seasonable norms. However,
it won`t be a calm day for most as westerly winds increase this
morning due to a building surface pressure and thermal gradient. The
strongest winds will likely be seen along the Cody Foothills and in
the upper Wind River Basin as a downsloping flow is established out
of the Absarokas and Winds. Gusts of 35 to 45 mph can be expected
here through the day with generally lesser magnitudes elsewhere.

The mostly clear skies expected this afternoon won`t last long as
the next system drops south into the area this evening. This
trough and associated upper level 120 knot jet will bring a
quick shot of moisture and colder air along and east of the
Continental Divide this evening through Saturday morning. Given
the speed of this system and a lack of deeper moisture, QPF
amounts are generally under a tenth of an inch across lower
elevations, focused mostly in the Bighorn Basin and Johnson and
Natrona counties. The Absarokas and Bighorns should pick up a
quick few inches of snow overnight with minimal travel impacts
expected. This trough will already be on its way out by mid-
Saturday morning, and any lingering showers should quickly give
way to widespread sunny skies around noon as drier air moves in
behind it.

Ridging builds in Saturday night, keeping dry and clear conditions
through Sunday morning. However, the unsettled pattern will continue
as the next system approaches Sunday afternoon. This is now looking
more similar to tonight`s system, with the majority of precipitation
expected along and east of the Divide as an open trough slides
across the northern Rockies through Monday morning. This one should
drop a little farther south, however, with precipitation also
extending to western Wyoming. Amounts are looking fairly similar as
well, with the mountains again picking up some light snow
accumulation. This system may also bring widespread strong
winds on Sunday ahead of a cold front that will push in Sunday
evening. This warrants watching for potential wind highlights,
but currently guidance keeps gusts below criteria.

Generally dry conditions and seasonable to slightly above normal
temperatures are then expected Monday through at least the middle of
next week as upper flow becomes more zonal. Further out, ensemble
cluster analysis currently favors above average 500 mb heights
through the end of the week, keeping mild and drier conditions
across the area into next weekend.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 410 AM MDT Fri Oct 17 2025

A few areas may have patchy fog this morning. The greatest
chance is at KWRL where the sky has cleared. Given clouds
lingering around KJAC where have removed the tempo group for fog
as of this moment. There is still a less than 1 in 5 chance for
fog around KLND and KRIW but not confident enough to include.
Otherwise, VFR conditions are expected for after 15Z Friday.
There will be a gusty wind with gusts over 25 knots possible at
times at the wind prone terminals of KCOD, KRKS and KCPR. A fast
moving cold front will bring the chance of showers after 06Z
Saturday largely along and East of the Divide. We had enough
confidence to include PROB30 groups at KCOD, KCPR and KWRL.
There is chance of a shower at KRIW and KLND as well but not
enough confidence to include at this time.

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...Hattings