textproduct: Western and Central Wyoming

KEY MESSAGES

- Showers and thunderstorms become more widespread today, 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 /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 440 AM MDT Thu Aug 13 2026

MVFR ceilings have developed across portions of Natrona County this morning and are expected to impact KCPR through 15Z. Rain showers will increase over western portions of the forecast area through the morning, but will not impact KJAC, KBPI or KPNA until 18Z to 20Z. Chances for showers and thunderstorms will impact the rest of the forecast area after 20Z and last through 02Z. MVFR conditions will be possible due to heavy rain. Convection will end from southwest to northeast after 00Z, with light showers lingering over northern portions by 06Z. Mountain top obscurations will develop by 18Z with the showers and remain in place through the rest of the forecast period. Marginal VFR to MVFR ceilings will be in place over northern portions after sunset this evening in the wake of the exiting showers. These conditions are expected to impact KCOD and KWRL by 06Z.

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