textproduct: Western and Central Wyoming

KEY MESSAGES

- Increased cloud cover will keep temperatures down a few degrees from yesterday's record high temperatures. Afternoon highs will still reach the 90s across the state.

- Scattered showers and thunderstorms will again develop early this afternoon and move to the northeast during the day. Monsoon moisture will be on the increase this morning, leading to better chances for thunderstorms than previous days.

- This pattern remains in place through the week, with above normal temperatures in the 90s and thunderstorms developing each afternoon.

UPDATE

Issued at 1007 AM MDT Mon Jul 27 2026

More clouds today as monsoonal moisture lingers over the area with a weak weather system moving through. Showers, and the occasional storm, has persisted through the morning. Thunderstorms should become more common by early afternoon as the shortwave moves through in conjunction with peak daytime heating. Gusts to 50 mph are possible with these storms. Interestingly, the HRRR model has a long line of gusty winds 50 to 55 mph accosted with the main push of showers and storms from western WY starting about 2pm, moving east through the area through about 9pm. Will see if this trend holds for each hour's update. Otherwise, have kept temperatures today less than yesterday given the expected cloud cover. Increasing smoke will also occur over the area, mainly northern WY tonight into tomorrow with the fires in the western US, as well as a plume of smoke coming from the southwest associated with the Nevada fires.

DISCUSSION

Issued at 231 AM MDT Mon Jul 27 2026

The dominant western ridging pattern holds firm again today, the the H5 ridge still anchored on the Four Corners region. The southwest tap of monsoon moisture continues today, and most models are bringing an increase in moisture during the next 6 to 12 hours. With warm temperatures still in place, daytime showers and thunderstorms will again develop late this morning and continue into the afternoon, moving to the northeast. The increased moisture and shortwave energy passing through today will bring a better chance for measurable rainfall from any thunderstorms, but the good forward motion of any storms will keep the chance for flooding low. Current cloud cover and any cover from thunderstorms today will keep temperatures lower than Sunday. Highs will still be above normal, but will hold in the low to mid 90s through the afternoon.

Tuesday will be similar to today, with very warm temperatures during the day. Ample moisture will tap this heat for scattered showers and thunderstorms during the afternoon. Midlevel support may be more limited, so showers might end up more isolated.

Wednesday another more vigorous shortwave comes around the ridge through Wyoming, which is expected to bring a much better chance for showers and thunderstorms. After this feature passes through, models are shifting the ridge slightly to the west through the rest of the week into the upcoming weekend. Models are noting a significant drop in moisture, as the monsoon moisture gets cut off. This would lead to much drier and warmer period heading into the weekend.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1155 AM MDT Mon Jul 27 2026

VFR conditions prevail over the next 24 hours. Rain showers over much of the region this morning will continue into the afternoon hours, and eventually there will be a 20 to 30% chance for most TAF sites to be affected by isolated thunderstorms, starting as early as 27/2000Z. Brief heavy rain reducing visibility, lightning, and erratic gusts 30 to 40 kt will be the biggest threat in the vicinity of storms. Thunderstorms will dissipate quickly after sunset, but isolated showers may linger overnight, especially over central Wyoming. Another day of isolated thunderstorms is forecast for Tuesday.

RIW WATCHES/WARNINGS/ADVISORIES

None.