textproduct: Western and Central Wyoming

KEY MESSAGES

- Warmer temperatures today, with highs reaching the mid-to- upper 80s west of the Divide and mid-to-upper 90s east of the Divide.

- Slightly lower moisture in the region brings isolated shower activity this afternoon, focused on southern WY.

- A surge of moisture into the state Wednesday brings widespread showers and thunderstorms. Monsoon moisture gets pushed out of the region for the end of this week, bringing warmer temperatures and ending rain chances.

DISCUSSION

Issued at 241 AM MDT Tue Jul 28 2026

The active monsoon pattern of the past couple weeks that has brought beneficial rainfall looks to be finally shifting the rest of the week. The H5 ridge placement centered on the Four Corners has been efficient in drawing moisture northward, and will continue today to trigger some shower activity for WY. Today, the focus of moisture looks to be more across southern WY, where the best chances for precipitation are setting up this afternoon. Some brief drying is noted across northern WY today, so shower activity will be more limited, and focused on higher elevations. The lower moisture for most of the state will bring decreased cloud cover, allowing temperatures to jump back well above normal. Areas east of the Divide will jump into the mid to upper 90s, while southern WY, with the better shower chances and cloud cover in the afternoon, will still reach the mid to upper 80s.

A final push of deeper monsoon moisture surges northward tonight, along with another shortwave wrapping around the ridge. This will bring much better chances for numerous showers and thunderstorms for the day Wednesday. Rainfall amounts will be beneficial again, but storm motions will be high enough to preclude most flooding concerns during the afternoon.

Once this shortwave sweeps northeast Wednesday night, the H5 ridge bulges to the west, effectively shutting the door on the monsoon flow, and instead drawing much drier air from the Great Basin into the state. This will effectively shut down rain chances for the rest of the week into the upcoming weekend. The ridge also bulges back to the north, bringing increasing temperatures across the state. Probabilities for 100 degree temperatures this weekend currently sit at >60% east of the Divide, and around 30% west of the Divide, including the greater Jackson region.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 501 AM MDT Tue Jul 28 2026

Main morning forecast issue is fog at KJAC. Moisture got trapped in the valley overnight, and has been meandering about, bringing brief vis reductions. Once daytime heating starts in the next couple hours, this cloud deck should lift and dissipate, with quickly improving flight conditions.

Showers and thunderstorms will return again this afternoon, but will be more isolated in nature. Most likely impacts will be at southern sites (KRKS/KBPI/KPNA/KJAC), where moisture is most available. As thunderstorms are expected to be isolated and brief, will stay with PROB30 groupings for the day. Shower activity will dissipate once daytime heating ceases, but increasing moisture form the southeast will likely keep midlevel cloud cover around the region through the night tonight.

RIW WATCHES/WARNINGS/ADVISORIES

Air Quality Alert until 1 PM MDT this afternoon for WYZ010.