Jackson Hole

000
FXUS65 KRIW 111118
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
518 AM MDT Fri Sep 11 2026

.KEY MESSAGES...

- Partly to mostly cloudy skies will continue this morning, with
  a slight chance of virga/rain showers over western portions  
  Friday morning.

- West winds, with gusts of 25 to 35 mph, will be widespread
  across the area again today. Temperatures will be slightly
  cooler today, with readings about 10 degrees cooler over far
  northern portions due to the proximity of a cold front. 

- Seasonal temperatures and dry conditions will be in place
  Saturday. West to southwest winds, with gusts up to 35 mph,
  will return again over western portions and over the Wind
  Corridor (southern Lincoln County to Natrona County). 

- Precipitation chances continue to trend northward, as the
  track of the storm stays to the north. Little to no
  precipitation is now expected from the storm on Sunday. The
  cold front will move through Sunday night, leading to freezing
  temperatures across western portions of the state again and a
  cooler day on Monday.

&&

.DISCUSSION...
Issued at 158 AM MDT Fri Sep 11 2026

Moisture has finally arrived over the Cowboy State, ending this
prolonged streak of critical fire weather conditions. Partly to
mostly cloudy skies continue over the state this morning, 
scattering out by midday day. Isolated showers to the west of 
PIH and SLC will continue to track eastward this morning and 
move over far western portions of the forecast area around 10Z. 
Virga is likely from these showers, but amounts around 0.05" 
will be possible over the Tetons/Gros Ventres and toward 
Union/Togwotee Pass. These showers may cross the Divide and move
over the Upper Green River Basin, after sunrise this morning, 
but will likely stay as virga. These showers are expected to end
by 18Z, with dry conditions expected through the rest of the 
day. There is a 10% chance for virga showers over areas east of 
the Divide late in the afternoon as a cold front drops 
southward. 

Widespread gusty winds will be the main concern again today, 
with west wind gusts of 25 to 35 mph occurring across the CWA 
this afternoon. The exception will be portions of the Bighorn 
Basin and the northern half of Johnson County. Northwest wind 
gusts up to 30 mph will occur in these areas as a cold front 
progresses southward through the afternoon. The front will pass 
through the Bighorn Basin and Johnson County by 00Z Saturday 
(6pm), quickly reaching the Casper area and Riverton between 01Z
and 03Z, eventually becoming stationary along the Divide by 
06Z. Temperatures will much cooler today, especially east of the
Divide, running about 5 to 10 degrees cooler. This will apply 
to far northern portions, due to the proximity of the front. 

Models have become aligned with the much talked about storm 
system for this weekend, with not much change from yesterday 
with the forecast track. The storm system is still forecasted to
drop southward along the West Coast tonight into Saturday. The 
aforementioned cold front will gradually retreat northward 
Saturday afternoon, due to an increase in southwesterly winds. 
The front looks to get pushed into the Bighorn Basin and further
north into Sheridan County through Saturday afternoon. Apart 
from isolated showers and thunderstorms over eastern portions of
Sweetwater County Saturday afternoon, conditions are expected 
to remain dry. Precipitation chances continue to be pushed 
northward as the storm stays further north in MT. Little to no 
precipitation is now expected from this storm. The associated 
cold front will push through the Cowboy State Sunday night, 
clearing the forecast area by 12Z Monday. Sub-freezing 
temperatures will return to western portions Sunday night/Monday
morning, with readings in the upper 30s to lower 40s elsewhere.
Dry and cooler conditions will be in place Monday, with highs 
in the 60s to near 70 degrees across the area. Conditions will 
remain dry with seasonal temperatures Tuesday. A storm system 
may impact the region Wednesday, but confidence is low at this 
point as colder, Canadian airmasses begin to drop southward.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 500 AM MDT Fri Sep 11 2026

Light showers are moving over western WY this morning and will
end by 14Z. The PROB30 group at KJAC remains in the forecast
with conditions at VFR. Mountaintop obscurations will continue
over the western mountains through 18Z. Otherwise, wind will 
increase at most terminals after 15Z ahead of a cold front that
will push into northern Wyoming after 21Z. This will lead to a 
wind shift at KCOD, KCPR, KRIW, and KWRL between 23Z and 02Z.
There is a 10 to 20% chance for MVFR to IFR ceilings behind the
cold front at KCOD and KCPR after 03Z.

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...LaVoie
AVIATION...LaVoie/Myers