textproduct: Western and Central Wyoming

KEY MESSAGES

- Shower and thunderstorm chances (30%-70%) exist between 12PM and 9PM along and east of the Continental Divide today, with the greatest coverage across the northwest Wyoming. Thunderstorms will be capable of gusty outflows up to 45 mph and lightning.

- Shower and thunderstorm chances exist each afternoon through at least Sunday, with more widespread showers and thunderstorms Friday through Sunday.

- High temperatures are forecast to be in the upper 70s to 80s each day. A few locations east of the Continental Divide could see highs in the 90s Wednesday through Friday.

DISCUSSION

Issued at 159 AM MDT Tue Aug 25 2026

Showers and a few embedded thunderstorms across southwest Wyoming are being supported by a shortwave disturbance early this Tuesday morning. This shortwave and the associated showers and thunderstorms will shift east across the Green River Basin and Sweetwater County and fizzle out by sunrise. This shortwave is rounding an upper level high that is centered over New Mexico and Texas.

Today, this upper high will build north into the Great Basin, with it's ridge axis extending into Idaho, placing Wyoming in west- northwest flow aloft. An embedded disturbance will traverse across the state and provide support for showers and thunderstorms this afternoon and evening. Shower and thunderstorm coverage is forecast to be less widespread compared to Monday and be largely orographically and diurnally driven along and east of the Continental Divide. Available moisture will be greatest across the aforementioned areas thanks to the west-northwest flow aloft and an associated boundary dropping into northern and central Wyoming. Thunderstorms are expected today with lifted indices ranging from -1C to -3C and BLCAPE values around 500 J/kg; however, height rises aloft will hinder severe thunderstorm potential. That being said, a few showers or thunderstorms will be capable of gusty outflows up to 45 mph. Showers and thunderstorms are forecast to develop between noon and 2PM across the higher terrain along the Continental Divide and shift east-southeast through the afternoon. Shower and thunderstorms largely come to an end by 9PM tonight, with a few light showers possible across northwest Wyoming until 11PM. With 700mb temperatures around 10C, anticipate high temperatures in the upper 70s and 80s.

The upper level ridge is forecast to begin a slow shift east across Wyoming early Wednesday and be east of Wyoming by Thursday evening. The ridge axis is currently forecast to be over western Wyoming on Wednesday as another weak disturbance propagates around it. Although there will be some support and available moisture aloft, height rises will keep shower and thunderstorm activity orographically and diurnally driven across southwest Wyoming and along and east of the Continental Divide. On Thursday, the ridge axis shifts east across Wyoming and places western Wyoming in west-southwest flow by peak heating. This west-southwest flow will funnel Pacific moisture into the area and provide support for diurnal shower and thunderstorm development across west and northwest Wyoming. Because the ridge is over Wyoming on both Wednesday and Thursday, temperatures are expected to warm into 80s west of the Divide and mid 80s to mid 90s east of the Divide both afternoons.

Ensemble guidance is in consensus that the Intermountain West will be positioned between the ridge in the central CONUS and an approaching Pacific Northwest trough on Friday. This places Wyoming in southwest flow with Pacific moisture funneling into the region. This looks to be the pattern Friday through at least Sunday morning as the Pacific Northwest trough shifts east. The specific details on timing, precipitation amounts, and coverage are unknown at this time, however, confidence in an active weather weekend is increasing.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1030 PM MDT Mon Aug 24 2026

VFR conditions currently and through the entirety of the period. Ongoing showers and some isolated thunderstorms pushing east of LND/RIW and nearing COD for the first hour or two of the period into the overnight hours. Otherwise, mid level clouds into Tuesday morning with light winds. Winds remain relatively light around 10kts or less outside of a brief gust at RKS after 20Z with daytime heating up to 18kts. Thunderstorms develop once again with HiRes data still not in line with each other similar to Monday but consensus is not as active, however. PROB30 groups after 20Z for BPI/PNA, 21Z for COD/RIW/LND, and 22Z for WRL through 00-02Z respectively. Lower but VFR ceilings and gusty outflows up to 35-40kts possible with the strongest cells through the mid afternoon to early evening hours. Storms exit to the east there after and weaken, with mid level clouds and light winds once again to end the period heading into Tuesday's overnight hours.

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RIW WATCHES/WARNINGS/ADVISORIES

None.