textproduct: Grand Junction

KEY MESSAGES

- Terrain based showers and thunderstorms will continue today and Tuesday. Gusty outflow winds and lightning will remain a threat.

- Dry lightning today and Tuesday could threaten new fire starts.

- Available moisture increases through the week with an uptick in convection and precipitation coverage and intensity expected Wednesday onwards. - Above normal temperatures will gradually cool closer to normal with a cooling trend brought on by monsoonal moisture Wednesday and beyond.

DISCUSSION

Issued at 1108 AM MDT Mon Aug 10 2026

Weak monsoonal moisture will continue to work beneath the ridge of high pressure centered over the region. Showers and thunderstorms will be much more isolated today and Tuesday with lighter moisture, favoring the terrain immediately west of the Divide. Drier air at the surface in our lower valleys will remain fertile for gusty outflow winds beneath decaying storms. These isolated storms will pose a lightning threat as well, despite the sunny skies in the valleys. This elevates the dry lightning threat and potential for new fire starts. Moisture begins to deepen on Wednesday and Thursday. This will increase precipitation chances around the region, with some wetting rains expected both days as the monsoonal flow awakens from its slumber. Ensemble models are advertising PWAT values in the 140 percent of normal range. While this isn't particularly impressive, it provides enough hope for wetting rains to break this hot and dry pattern. Widespread flooding is not expected, but a few localized showers could pose headaches for flashy terrain and burn scars.

The influx of moisture will also help with moderating afternoon temperatures. Highs will trend above normal this afternoon and Tuesday. Increasing cloud cover and outflows from mountain showers will begin to work on some of our warmer valleys on Wednesday, and to a greater extent, Thursday and beyond. While a big push of monsoonal moisture is not expected in the extended period. There is some good news in the persistence of this weaker moisture. This forecast will likely ebb and flow over the next week. Afternoon showers and thunderstorms will continue on the mountains and over some valleys. Should we see some repeat showers in favored locations, this could lend itself to a greater flash flood risk. Outdoor enthusiasts and residents of nearby burn scars will want to stay abreast of changing forecast conditions as we move back out of the hot, dry pattern.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1108 AM MDT Mon Aug 10 2026

Convective debris clouds will continue to drift across the region through this evening, with mainly VFR cigs and vsbys expected through Tuesday morning. Moisture will slowly continue to increase across the region this week, slowly increasing the areal coverage of showers and storms today through Tuesday afternoon for some higher elevation TAF sites. Gusty outflow winds and brief periods of MVFR cigs/vsby are possible in and around any thunderstorms that do develop.

GJT WATCHES/WARNINGS/ADVISORIES

CO...None. UT...None.