textproduct: Western and Central Wyoming

KEY MESSAGES

- The Extreme Heat Warning continues through 9 PM Tuesday, as daytime high temperatures run 10 to 15 degrees above normal.

- Isolated showers and thunderstorms, mainly over the Absaroka, Gros Ventre, and Wyoming Ranges, continue until around sunset Monday. The primary hazard from these showers and storms will be gusty outflow wind 35 to 45 mph.

- Temperatures trend slowly downward beginning Wednesday through the end of the week, with shower and thunderstorm chances slowly increasing.

UPDATE

Issued at 1226 PM MDT Mon Jul 13 2026

No notable changes with this update. Temperatures remain hot today, with most lower elevation locations seeing highs 95 to 105 degrees. Still, with the high pressure system shifting slightly east, enough moisture will be around to get some clouds over the area, mainly the western mountains. A few could be virga or light showers. Gusty outflow winds are the main hazard with any of these.

DISCUSSION

Issued at 350 AM MDT Mon Jul 13 2026

A day after several all-time record highs were broken, today will not bring much relief. The center of the dominating high pressure system has now shifted farther east. This will allow slightly cooler air to work its way south into Wyoming today, already noted with a northerly breeze across the northern Bighorn Basin early this morning. While this will bring highs down by 5 to 10 degrees across northern Wyoming...that still puts nearly all lower elevations in the 95 to 105 degree range today. Elevated moisture will increase slightly, leading to more cumulus clouds and virga, especially across the western half of the state. With large temp/dewpoint depressions at the surface (60-70 degrees), virga will carry a strong but isolated wind threat this afternoon. The lack of a more widespread breeze will be the limiting factor on fire weather conditions today; while humidity will drop into the single digits for much of the area, generally lighter wind precludes the issuance of any fire weather hazards.

Tuesday will bring very similar conditions, with temperatures again peaking in the 95 to 105 degree range, perhaps slightly higher again across the Bighorn Basin as heights rise subtly. Convection coverage will ramp up a little further as moisture increases, again mostly of the virga form. The hot temperatures will remain the primary weather impact; the Extreme Heat Warning will continue through sunset Tuesday.

The ridge is expected to shift farther east on Wednesday. This should allow for increasing monsoonal moisture advection and an uptick in convection, especially as shortwaves progress through the flow over the area. Temperatures will decrease in response, though only marginally - high are still expected to be in the 90s to low 100s across the lower elevations. Moisture advection will be further amplified on Thursday and Friday as PWAT values approach one inch. Accordingly, rain chances will increase across the area beginning Wednesday, with Thursday appearing most favorable for widespread shower and thunderstorm coverage at the moment.

Ensemble cluster guidance continues to favor anomalously high 500mb heights through the weekend. While this would not bring any big pattern changes, additional smaller disturbances and continued monsoonal moisture is likely to lead to more rain chances across the area.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1030 PM MDT Mon Jul 13 2026

VFR conditions expected throughout the period at all TAF sites. Winds will primarily be light (10kt or less) through the period as well. The main exceptions will be outflow winds from afternoon convection and easterly winds with gusts of 20 to 25kt after 19Z at KCPR, KRKS, KRIW and KWRL, with KCPR and KWRL having the higher gusts. Scattered showers and thunderstorms will develop again over the western mountains Tuesday afternoon and impact KJAC, KBPI, KPNA and KCOD between 21Z and 03Z. Strong outflow winds will be the main threat, but lowered visibility due to heavy rain could occur if a storm moves directly over the site. PROB30 groups have been added to these sites, accordingly.

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

Extreme Heat Warning until 9 PM MDT Tuesday for WYZ003>006-010- 011-013-016>020-023-025>030.