textproduct: Grand Junction

KEY MESSAGES

- Daily afternoon thunderstorm chances through the rest of this week, mainly on the higher terrain of western Colorado and eastern Utah.

- Localized heavy rainfall continues to pose a threat to flash flooding over burn scars and susceptible terrain.

- Daytime highs will run 5 to 10 degrees above normal through Friday.

- Cooler and wetter pattern change this weekend into early next week with more widespread showers and thunderstorms, with highs near to slightly below normal.

DISCUSSION

Issued at 1020 PM MDT Tue Aug 25 2026

HOT REST OF THIS WEEK:

The high pressure ridge will continue to retrograde westward across New Mexico and Arizona with its center south of the Four Corners. We will continue to recycle moisture underneath with PWAT anomalies holding steady at around 110 to 140 percent of normal through Friday. Meanwhile, high temperatures will continue to remain around 5 to 10 degrees above normal. Forcing will remain limited so expect storms to form over the high terrain each afternoon. Frequent lightning and gusty winds will be possible from any storms that form, along with localized heavy rain. Should storms form over a sensitive area, or train over the same area, flash flooding will be possible, along with debris flows associated with recent burn scars but this threat does appear localized through Friday. A little bit drier air does get pulled in as well by Friday with some gustier winds ahead of a low pressure trough that moves into the Pacific Northwest, which may result in localized critical fire weather conditions.

COOLER AND WETTER PATTERN THIS WEEKEND INTO NEXT WEEK:

The pattern does look to change once again by this weekend as this low pressure trough moves into the Pacific Northwest, nudging the high to the east and shifting the flow to southwesterly. This will help draw up another surge of monsoonal moisture as PWAT anomalies jump towards 160 to 180 percent of normal. This low lifts across the Intermountain West and Northern Rockies Saturday into Sunday, bringing some robust shortwaves through the moist, southwest flow which should result in more widespread showers and thunderstorms with heavy rain potential. This pattern looks to last through early next week as a large scale trough remains over the Pacific Northwest with several shortwaves moving through the base of this trough. So this weekend into next week is trending wetter and cooler with highs near to a few degrees below normal as we transition out of August and into the first week of September.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 518 AM MDT Wed Aug 26 2026

Some clouds will drift overhead this morning before convection starts after 18Z. Isolated showers and thunderstorms will form over the higher terrain this afternoon with the best chances for convection over KGUC and KTEX. Outside of convection, generally light winds are expected. VFR conditions will continue, might be some brief MVFR under stronger showers/storms.

GJT WATCHES/WARNINGS/ADVISORIES

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