textproduct: Western and Central Wyoming

KEY MESSAGES

- Scattered showers and thunderstorms are expected through this evening as they move from southwest to northeast across the area. Strong wind gusts of 40 to 60 mph are possible with this activity.

- Elevated to near critical fire weather conditions are expected through the afternoon across much of central Wyoming.

- Scattered showers and thunderstorms are again expected on Sunday, though less widespread with the best chances across western Wyoming. Elevated to near-critical fire weather conditions will continue for much of the area.

- The unsettled pattern will persist through next week, with mild afternoon temperatures and several chances for moisture. A late week system may return cold morning temperatures (15-25 degrees) to lower elevations.

UPDATE

Issued at 1157 AM MDT Sat Apr 11 2026

Convection is beginning to increase across western and southern Wyoming late this morning as a shortwave arrives ahead of an approaching upper low. Continued diurnal heating will allow MLCAPE values to build to 100-500 J/kg across the area, with showers and thunderstorms expanding in coverage from west to east over the next couple of hours. The main concern with this activity will be strong outflow wind gusts given the relative dry, well-mixed boundary layer (DLCAPE values of 500-1000 J/kg). This risk will extend through mid evening, with the last storms expected to exit the area between 9 PM and midnight.

DISCUSSION

Issued at 145 AM MDT Sat Apr 11 2026

As an advancing trough makes it to northern California today, southwest flow aloft increases across Wyoming, bringing better moisture to the area. In addition, a trough in advance of the main system passes through today. These factors combine to bring increased precipitation chances today, with showers being able to produce rain that reaches the ground. The main push of this shortwave starts late this morning, with shower and thunderstorm chances increasing from the southwest through the afternoon, and then decreasing from the southwest to northeast between about 6pm and midnight. Everywhere will have a chance for rain today (snow levels around 9000 feet). The best chances will be west of the Continental Divide, where the better moisture will be. The current forecast depicts of blend of hi-res models, with the reality being that it is nearly impossible to determine exactly where a shower or storm could occur today, but they will be around. Everywhere has at least a 20 percent chance, though actual chances vary to be as high as 80 percent (mainly west of the Divide). Many models seem to depict a cluster of rain showers over Sweetwater County this afternoon, so confidence in rain is better there. The main hazard with any showers or storms would be outflow gusts, which could be up to about 60 mph.

The other hazard today will be wind, and some fire weather concerns with it. Moisture does increase today, especially west of the Divide, but minimum humidity values around 20 percent are likely for basins east of the Divide, driest for Johnson County. It is also going to be windy today, a result of a tightening pressure gradient. Gusts 25 to 40 mph will be common, and for these drier places, near critical fire weather conditions could occur.

For Sunday, precipitation chances remain (though much more limited compared to today), mostly along and west of the Divide, though some "spill-over" is likely. Current projected positioning of the incoming low would favor the western mountains (i.e. Absarokas, Tetons, Yellowstone) the most. Gusty southwest winds 25 to 40 mph continue during the day as well, so elevated to near critical fire weather conditions remain a concern.

For Monday and Tuesday, the model trend continues to be for a weaker and drier system, unfortunate news for those wishing for precipitation. Liquid totals have dropped once again, with very limited chances for low elevation basin locations. Elevated to near critical fire weather looks to continue as well as gusty winds occur.

Looking further ahead, there is growing confidence in a colder system towards the end of next week (Thursday-Saturday). This system has the potential to bring morning low temperatures in the low 20s, with multiple mornings in a row under 30 degrees. This is a heads up to those with sprinklers or vulnerable vegetation.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1059 AM MDT Sat Apr 11 2026

VFR flight conditions are largely expected through 18Z Sunday with scattered shower and thunderstorm chances this afternoon. At all terminals, there is a 30 percent chance of thunderstorms beginning as early as 19Z at KJAC followed by all other terminals. Because showers and thunderstorms will move southwest to northeast, it is expected that west of the Divide terminals (KJAC, KRKS, KPNA, and KBPI) will generally see chances before east of the Divide terminals (KRIW, KCPR, KCOD, KLND, and KWRL). Showers or thunderstorms should also end from southwest to northeast between 01Z and 04Z. Gusty 40kt to 50kt winds are possible at any terminal in or with nearby showers or thunderstorms. Isolated severe gusts near 60kts cannot be ruled out. MVFR conditions will be possible in the heavier showers and thunderstorms with occasional mountain obscurations.

Gusty southwest winds are also expected outside of any showers or thunderstorms with gusts generally between 25kts and 35kts. These gusty winds should diminish around or shortly after sunset with relatively light winds overnight at most terminals. KCPR is the exception with winds remaining breezy the entire TAF period.

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.