textproduct: Western and Central Wyoming

KEY MESSAGES

- Isolated showers and thunderstorms will continue through the evening. Brief heavy rain under the stronger storms will remain a threat. Coverage will decreases overnight.

- Chances for showers and thunderstorms continue this weekend, but will be more isolated in nature, with cool and moist conditions persisting.

- A cold front looks to move through mid-week, keeping temperatures 5 to 10 degrees below normal through week's end.

UPDATE

Issued at 130 PM MDT Fri Aug 14 2026

Scattered showers and thunderstorms have begun developing over western Wyoming as expected, and these will move eastward across the state this afternoon and evening. The atmosphere remains moist, so brief heavy rain and isolated lightning will remain the primary threats, with localized flash flooding possible where multiple storms happen to track over the same location. Thankfully the upper atmospheric flow will be strong enough to keep thunderstorms moving east to northeastward at 15 to 20 mph, thus reducing the threat of flooding due to stationary storm motions. Additionally, there is less CAPE available as fuel for storms, with only 300 to 500 J/kg in the region, meaning weaker storms overall than yesterday (Thursday). Storms decrease in coverage and intensity after sunset, but showers will linger overnight, especially across southern and central Wyoming as the next passing shortwave approaches.

No major changes to the ongoing forecast or forecast reasoning for the next 7 days. Brought in the latest high-resolution model winds and precipitation chances for the next 48 hours to best capture these details in the shorter-term forecast.

DISCUSSION

Issued at 155 AM MDT Fri Aug 14 2026

Light showers over the Bighorn Basin will continue to exit toward MT in the next couple of hours this morning. Light showers over Sweetwater County will gradually dissipate during this time as well. Areas of low clouds/fog have developed this morning in the wake of yesterday's precipitation. This is expected to lift out by 16Z.

Convection will not be as extensive today, being more scattered along and north of a Afton to Midwest line. Showers and thunderstorms will develop over far western portions by 18Z, moving toward the northeast and moving over the Bighorn Basin by 21Z and the Wind River Basin by 22Z/23Z. Heavy rain and localized flash flooding will continue to be the main threat from these storms as PWAT values remain abnormally high, ranging between 0.6" to 1.1". Convection will begin to end for most areas by 01Z, with showers and thunderstorms exiting Johnson County by 03Z. Winds (outside of any outflow boundary) will be a bit stronger today, with gusts of 20 to 25 mph occurring from Kemmerer to Casper with the stronger gusts occurring over South Pass and portions of Natrona County. Highs will continue to be slightly below normal, ranging from the middle 70s to lower 80s.

Precipitation chances will not be as extensive over the weekend, with convection being isolated across the CWA both days. Temperatures will continue to be slightly below normal Saturday and rising a few degrees on Sunday. This trend will continue into Monday, as the flow aloft becomes more zonal once again. A trough will begin to drop southward over the PACNW/Northern Rockies Tuesday, with a cold front moving over areas east of the Divide Wednesday. Showers and thunderstorms will be possible Monday through Wednesday, with Monday being the warmest day. Dry conditions look to return by Thursday as an area of high pressure rebuilds over the Desert Southwest and a ridge axis extending over ID. This will turn the flow aloft more northwesterly and likely pull wildfire smoke back into the region.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 509 PM MDT Fri Aug 14 2026

Most convective activity will end within the first hour of the TAF period, but some lingering light showers remain possible before 06Z. Consistent moisture will keep scattered rain showers and thunderstorms in the forecast for Saturday afternoon. Most convective activity will be across the northern half of the area. Brief MVFR to IFR conditions will be possible with heavier showers and storms Saturday afternoon. There is a low chance (15%) of some showers in the area Saturday morning.

Wind will generally be around 10 knots to start the TAF period, becoming light this evening by 02-04Z at most terminals. Otherwise, wind will be outflow driven from convection for a couple of hours to begin the TAF period. Mountaintop obscuration will occasionally occur across western mountains before 06Z.

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

RIW WATCHES/WARNINGS/ADVISORIES

None.