260
FXUS65 KRIW 101105
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
505 AM MDT Mon Aug 10 2026

.KEY MESSAGES...

- Hot, dry, and breezy conditions will persist through Tuesday
  and result in widespread near-critical to critical fire
  weather conditions.

- Virga showers and dry thunderstorms will develop early in the
  afternoon over central and southern portions of the forecast
  area. Gusty 40 to 55 mph outflows and lightning are the
  primary threats.

- Wildfire smoke is expected to remain present across the state,
  especially the northern half of Wyoming, through at least
  Tuesday. This will continue to bring reduced visibilities and
  poor air quality.

- Increased rain chances (50% to 80%) and cooler temperatures
  look to arrive by Wednesday and continue into the weekend.

&&

.DISCUSSION...
Issued at 224 AM MDT Mon Aug 10 2026

The Four Corners high will remain in place, along with a zonal flow
pattern over the Cowboy State today. Similar conditions from Sunday
will return across the area with temperatures remaining above normal
and critical fire weather conditions in place. Westerly winds, with
gusts of 25 to 35 mph, will increase after 18Z across much of the
CWA. The notable exception will be most areas of the Bighorn Basin,
where winds will struggle to gust up to 20 mph. Virga showers/dry
thunderstorms will also develop over the southern half of the
forecast area early in the afternoon, with the Wind River Mountains,
the northern end of the Salt River/Wyoming Ranges and the western
half of Sweetwater County having the best chances for a shower or
storm. Wind gusts up to 55 mph will be possible due to large
dewpoint depressions that will be in place once again this
afternoon. Most of the convection will end across the area by
sunset. Red Flag Warnings have been reissued for areas east of the
Divide and southern portions of the CWA from 18Z to 03Z Tuesday
(12PM to 9PM) due to aforementioned critical RH values, gusty winds
and dry thunderstorms. Skies will remain hazy from smoke will
continue today, especially over northern portions.

Another day of hot and dry conditions return Tuesday. Highs in the
middle 90s will occur again for most areas east of the Divide and
upper 80s/lower 90s west of the Divide. Wind gusts of 25 to 35 mph
will occur again, but are not expected to be as widespread. Red Flag
Warnings will likely only be needed for a few zones as a result.
Needless to say, the hazy/smoky skies will continue across the area
as well.

The pattern will begin to shift Wednesday, as the Four Corners high
weakens and erodes and the flow aloft over the Cowboy State turns
more southwesterly irt an approaching trough. Precipitable water
values will increase through the day as a result, with values
approaching 1". This won`t be as strong as the surge of monsoonal
moisture that occurred a few weeks ago in July, but the threat for
locally heavy rain/localized flash flooding will certainly be in
place. Convection looks to be rather isolated so far, but
temperatures will be slightly cooler from increased cloud cover and
a weak cold front. This trend continues into Thursday, with
temperatures dropping into the 70s to near 80 degrees. Thursday also
looks to be the best chance for widespread precipitation, especially
across western portions of the state, as the trough moves over ID.
The cooler conditions continue Friday, as the trough exits over the
Northern Plains. Convection will be more widely scattered as weak
shortwaves move over the area through the continued southwest flow
aloft. The threat for locally heavy rain will also continue as the
monsoonal moisture stays in place. This trend will continue through
the weekend, as shortwaves continue to rotate over the region from
the southwest.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 502 AM MDT Mon Aug 10 2026

VFR flight conditions are largely forecast through at least 06Z
Tuesday. However, brief periods of MVFR visibilities are possible due
to wildfire smoke over the area. Confidence remains too low to
time the thicker smoke and lower visibility. Some improvement
from smoke is forecast at most terminals later this morning into
the early afternoon. Winds are forecast to increase as early as
15Z at KCPR, increasing with frequent gusts in the 18kt to 30kt
range after 18Z for the remaining terminals. These gusty winds
are forecast to decrease around sunset. Scattered virga showers
and dry thunderstorms are forecast across the southern half of
the forecast area between 20Z and 02Z Monday, with gusty 35 to
40 kt outflows possible.

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

&&

.FIRE WEATHER...
Issued at 224 AM MDT Mon Aug 10 2026

Red Flag Warnings have been reissued for zones in central and
southern portions of the state. Hot temperatures, critical RH
values and gusty winds will return to these areas, along with
chances for dry thunderstorms. Outflow wind gusts up to 55 mph
will be possible from any shower or thunderstorm due to the dry
conditions. Similar conditions return Tuesday and Warnings may
be needed again, but not all zones will reach criteria. Winds do
not look to be as widespread with no threat for dry
thunderstorms.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Air Quality Alert until noon MDT today for WYZ001>020-022>030.

Red Flag Warning from noon today to 9 PM MDT this evening for
WYZ277>281-283-285>287-289-300.

&&

$$

DISCUSSION...LaVoie
AVIATION...LaVoie/Gerhardt
FIRE WEATHER...LaVoie