233
FXUS65 KRIW 110758
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
158 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 /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 959 PM MDT Thu Sep 10 2026

A disturbance will continue to produce mid and high clouds through
the overnight hours. KJAC remains the best terminal to see brief
showers from this, and confidence has increased enough to introduce
a PROB30 group there between 09Z and 14Z. VFR conditions are
expected to prevail, though occasional mountain obscuration is
expected. Otherwise, wind will increase Friday morning at most
terminals 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.

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...Myers