939
FXUS65 KRIW 121758
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1158 AM MDT Fri Jun 12 2026

.KEY MESSAGES...

- Breezy winds, mostly clear skies, and afternoon high
  temperatures about 5 to 10 degrees warmer than Thursday.

- A weak cold front pushes through Friday night with shower
  activity limited to the northern and eastern areas (40-60%).
  Temperatures Saturday 10 to 15 degrees cooler than Friday and
  more seasonable for this time of year.

- Mainly dry and warming trend Sunday through Thursday with the
  next system to impact the area by week`s end into the weekend.

&&

.DISCUSSION...
Issued at 100 AM MDT Fri Jun 12 2026

IR currently shows mainly clear skies across the CWA with the
cooler cloud tops well north into Montana and Canada. The main
low that affected the area the past few days is now
progressively shifted well east and north into Canada affecting
the Great Lakes to the Ohio River Valley with the main finger of
the PFJ north of the US Rockies pushing into the upper Great
Plains. The deformation trough extending west from the upper low
will push to the south clipping the CWA Friday night that will
drop a weak cold front east of the Divide bringing some weak
shower activity after midnight into Saturday morning. Much of
the coverage will be across the Bighorns and eastern counties
(~60%) but some still possible for the Bighorn Basin to the Owl
Creeks (~40%) before weakening as it moves further south.
Thunderstorm activity will be limited to the higher terrain of
the Bighorns where the better instability will be (100-200
J/kg) in regards to fire weather issues due to lightning but
will be pushed out by mid Saturday morning. Higher elevation
snow likely for the northern Bighorns where CAMs are showing a
couple inches of accumulation but no impacts to the lower
mountain passes.

Otherwise, Friday afternoon will see mainly clear skies and
warmer temperatures from Thursday around 10 degrees. Breezy
winds east of the Divide but nothing of note being at or below
20 to 25 mph. Behind the weak front Friday night, Saturday will
be 10 to 15 degrees cooler than Friday with weaker winds but
more northeasterly heading into Sunday as well. Warming trend
Sunday through Thursday back into the mid to upper 80s east of
the Divide and 70s to near 80 to the west. Isolated storms
Sunday afternoon but limited in coverage (10-20%) for the
Bighorns but dry expected through Thursday. This will be when
the next system will affect the area as the deepening northwest
flow allows for increasing divergence aloft. Models are not as
consistent on precipitation coverage but something to keep an
eye on going forward. Fire weather looks to be limited to
elevated Sunday through Thursday even with the warmer
temperatures and lower RH values, but wind looks to generally be
weak to a slight breeze throughout.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1158 AM MDT Fri Jun 12 2026

Skies will remain mostly clear today with VFR conditions
through sunset. Most terminals will see a west to northwest wind
this afternoon with gusts of 20 to near 30 knots. KCOD will see
a sharp northerly wind shift around 23Z as a cold front pushes
south into the area. This will reach KWRL around 01Z, weakening
as it approaches central Wyoming between 04Z and 06Z. Lower
clouds and showers will follow overnight, with MVFR ceilings at
KCOD and KWRL between 09Z and 12Z and then at KCPR by 15Z
Saturday. The best chance for precipitation impacts will be at
KCOD and KWRL, though low confidence precludes more than a
PROB30 mention. Conditions will begin improving late in the
period toward 18Z Saturday.

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

&&

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

&&

$$

DISCUSSION...Lowe
AVIATION...Myers