463
FXUS65 KRIW 221111
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
511 AM MDT Fri Aug 22 2025

.KEY MESSAGES...

- Cooler temperatures today east of the Divide, with similar temperatures
  west of the Divide compared to yesterday. Highs will
  generally be in the mid-80s.

- Showers and thunderstorms are possible (15% to 60% chances)
  today across much of the area. The strongest storms are
  capable of wind gusts 30 to 50 mph and small hail.

- The weather pattern remains cool, with shower and thunderstorm chances
  into next week. Better moisture makes its way to the area
  early next week.

&&

.DISCUSSION...
Issued at 158 AM MDT Fri Aug 22 2025

Today`s forecast looks similar to yesterday. The area will be in
between an upper-level low centered in Canada and an upper-level
high centered around the Four Corners area. Northwest flow aloft
keeps the cooler temperatures from yesterday in place, especially
east of the Continental Divide, where the trough`s influence is
greater. Highs today are in the mid-80s for most locations, with the
cooler areas being around Johnson County where the highs are in the
mid-70s.

The moisture from yesterday also continues today, with afternoon and
evening showers and thunderstorms possible. Though an isolated (10%
or greater) shower or storm is possible anywhere, the best chances
(20%-60%) occur from an Afton to Cody line and east. Hi-res models
are in best agreement for storms across Sweetwater County, northeast
into southern Johnson County (which includes southeast Fremont
County and Natrona County). This area is also where the best chances
for stronger storms would be, including gusty outflow winds and
small hail. Gusts 30 to 40 mph would be most common with the
stronger storms, though isolated gusts to around 50 mph are
possible. Showers and storms will linger late, possibly to around
sunrise Saturday morning.

For Saturday, the upper level pattern has the high shift westwards.
This will temporarily limit moisture into the area, so chances for
showers and thunderstorms greatly decreases. There will likely still
be a few that pop-up during the afternoon, but would be limited in
coverage and favored to initiate over the mountains. Sunday,
moisture rotating around the high makes it to the area, with shower
and storms chances increasing again. Coverage of rain chances
increases further Monday as monsoonal moisture makes it to the area.
The chances for wetter showers and storms therefore also increases
for Monday. This wetter and cooler pattern looks to continue through
next week. Though too early to accurately forecast liquid amounts for
next week, the pattern would favor higher amounts west of the
Divide, with the EFI/SOT highlighting southern and southwestern
Wyoming for higher than climatological liquid amounts (QPF).

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 507 AM MDT Fri Aug 22 2025

Another round of showers and thunderstorms today, but will be
slightly more isolated, and confined to higher elevations. Best
chances for precip at TAF sites remain at KCPR and KRKS, with
lower chances for remaining sites east of the divide.

Another push of northeast winds wraps into central WY this
evening and overnight, bringing a deck of lower cloud cover for
KCPR/KBYG/KLND/KRIW overnight. Cigs should stay 6000 to 8000,
but some tempo cigs lower than this may occur overnight.

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...
Air Quality Alert until 1 PM MDT this afternoon for WYZ005.

&&

$$

DISCUSSION...Wittmann
AVIATION...Straub