textproduct: Grand Junction

KEY MESSAGES

- Daily chances for showers and thunderstorms continues to highlight the forecast with less coverage Friday and Saturday before becoming more widespread again Sunday into next week. - Heavy rainfall, lightning, small hail and outflow winds up to 40 mph will continue to be the primary risks for storms.

- Storms have the ability to produce flash flooding and debris flows in vulnerable terrain, including areas near and downstream of burn scars.

DISCUSSION

Issued at 1041 PM MDT Thu Jul 23 2026

FRIDAY AND SATURDAY:

Storm coverage is expected to be much less on Friday than previous days as a shortwave exits to the east taking the deeper moisture with it and the high pressure center meanders back to the west, allowing a drier air mass to filter into the area from the northwest. This will only be temporary mainly for Friday and Saturday with high temperatures rising back to triple digits for lower elevation valleys. Even though moisture content will be less than previous days with the deepest monsoonal plume to our west over Nevada and western Utah once again, we should still hold onto enough moisture to recycle it as it remains trapped under the high, resulting in daily afternoon convection over the high terrain. While widespread flooding concerns will be limited, we will still see some stronger storms capable of heavy rain and resulting in an isolated risk of flash flooding over burn scars, already saturated soils and areas of steep terrain.

SUNDAY INTO NEXT WEEK:

The deeper moisture returns beginning Sunday but more so Monday through middle of next week as the high shifts eastward, allowing the deeper moisture to shift over the western slope with southerly flow on tap for a more favorable trajectory. PWAT anomalies will go from a reduced 120 to 140 percent of normal Friday and Saturday, to 160 to 180+ percent of normal by early to mid next week. This should result in more widespread daily storm coverage as well Sunday through at least mid next week. We should see continued heightened potential for heavy rain and flooding concerns especially over burn scars, vulnerable terrain and where training storms occur. Our high temperatures should dial back some with this increasing moisture, at least not as hot with triple digit heat with warm overnight lows as well. Models are indicating a tropical system moving off the Baja westward out into the Pacific around the high, which could draw some additional moisture northward during that Monday to Wednesday timeframe.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 508 PM MDT Thu Jul 23 2026

Thunderstorm activity is gradually diminishing at most terminals this evening. The overnight period will see generally light winds with terrain driven tendencies. Skies will generally clear out after this push of cloud cover moves eastward. Mid level clouds will begin to develop again by Friday afternoon. There is a chance for afternoon thunderstorms Friday mostly confined to the high country terminals. Included PROB30 groups to account for that. All that being said, VFR conditions will prevail.

HYDROLOGY

Issued at 1041 PM MDT Thu Jul 23 2026

Isolated to scattered thunderstorms capable of producing heavy rain are expected to develop Friday afternoon as well as through the weekend, mainly over higher terrain, although coverage will be less than previous days. Rainfall rates of 1-2 inches per hour will be possible with the stronger storms. These rates could lead to flash flooding and debris flows, especially over steep terrain and recent burn scars. Also, rain over the past several days has lead to saturated soils, which increase the chances for excessive runoff.

As a reminder: Keep an eye on our forecasts through the end of the week and stay tuned for updated hydrology alerts if visiting or if you reside below terrain vulnerable to flash flooding and/or debris flows. Dry creeks and arroyos can fill quickly and without warning from storms miles away.

GJT WATCHES/WARNINGS/ADVISORIES

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