243
FXUS65 KRIW 130755
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
155 AM MDT Thu Aug 13 2026

.KEY MESSAGES...

- Showers and thunderstorms become more widespread on Thursday,
  with all locations seeing rain chances (60-80%). Heavy rain
  and localized flash flooding will be the main threat from the
  storms, especially east of the Divide. Lincoln County and the
  Green River Basin will have the best chances for
  thunderstorms.

- Cooler conditions with continued shower and thunderstorm
  chances persist into the weekend.

&&

.DISCUSSION...
Issued at 152 AM MDT Thu Aug 13 2026

Chances for precipitation will be widespread across the CWA today.
The threat for heavy rain and localized flash flooding is still in
the forecast, with areas east of the Divide having the better
chances. Precipitable water values will be higher here, ranging
between 1 and 1.3". WPC Excessive Rainfall Outlook continues to have
a Slight risk in the forecast for Johnson County and portions of
Natrona County (mainly along and east of I-25). Showers will move
northward over Lincoln County and the Green River Basin after
sunrise and spread over western portions through the rest of the
morning. Scattered showers and thunderstorms will develop across the
rest of the CWA between 18Z and 20Z, moving toward the northeast
through the afternoon. Convection will begin to decrease by 00Z,
ending from southwest to northeast through the evening. Light
showers will still be over northern portions by 06Z and linger
through the rest of the night. Thunderstorms will be possible across
the area this afternoon, with portions of Lincoln and Sublette
counties having the best chances as as shortwave from NV/UT moves
over this region.

Convection will not be as extensive Friday, being more scattered
through the day along and north of a Afton to Midwest line. Heavy
rain and localized flash flooding will continue to be the main
threat from these storms as PWAT values remain abnormally high,
ranging between 0.7" to 1.1". The hazy/smoky skies looks to no
longer be an issue by Friday, as the southwest flow aloft cuts off
the source region and the atmosphere becomes more mixed.

The cooler and wetter pattern will continue through the
weekend, with showers and thunderstorms possible each day. The
threat for heavy rain will not be as strong by Sunday, as a bit
more drier air filters into the region. More drier conditions
look to return by Monday, but temperatures are trending to
remain seasonal for the early part of next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1030 PM MDT Wed Aug 12 2026

VFR conditions throughout the period at all TAF sites. Lingering
light rain showers west of the Divide to include KCOD that will
slowly dissipate overnight ahead of another round Thursday
afternoon. All locations will see a decent chance for rain
shower activity (40-60%) with isolated storms near KBPI/KPNA
during the afternoon (20-30%). Any shower activity will linger
through sunset and push east/dissipate towards the end of the
period and overnight into Friday morning. Otherwise, relatively
light winds 10kts or less, except an occasional breeze at KCPR
outside of the gusty outflow potential with storms near KBPI/KPNA.
There is a slight chance (10-20%) for MVFR ceilings at KCOD at
the end of the period and overnight Thursday, but confidence is
low and is mentioned as a 05Z line for this cycle.

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...

&&

$$

DISCUSSION...LaVoie
AVIATION...Lowe