textproduct: Grand Junction

KEY MESSAGES

- Showers and storms will continue through next week each afternoon and evening.

- Heavy rainfall, lightning and outflow winds will be the biggest concern with any convection. Some small hail will also be possible.

- A Flash Flood Watch has been issued for portions of the San Juans, including the Gold Mountain Burn Scar, as heavy rain over the last few days has increased the chances for flash flooding.

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

DISCUSSION

Issued at 1019 AM MDT Sun Jul 19 2026

Rinse and repeat. That's the going forecast as high pressure remains fairly stagnant across the area. Add to that PWATs of 150 to 200% of normal, higher CAPE values indicating plenty of instability...all the ingredients are in place (and will remain so) for the next several days for showers and thunderstorms. Some gusts of 30 to 40 mph have been noted under the stronger cells but the biggest concern remains heavy rainfall and lightning. This is a two- edged sword, however. The rain is good for the drought, not so good for the burn scars. It's not just the burn scars that have occurred this year either. This also includes burns scars from previous years. If heavy rain does move over any burn scars, the chance for flash flooding and debris flows increases. To that end, did issue a Flash Flood Watch for a portion of the San Juans, to include the Gold Mountain Burn Scar, for this afternoon and evening. Heavy rain over the last few days has saturated the area so if we get another shot of heavier rain today, we'll see an increased chance for Flash Flooding.

All that being said, we'll be seeing convection through next week with some days more active than others. The location of the high will also cause storm motion to change becoming more southerly versus easterly as we're seeing now. This won't occur until next week so we'll see if this pans out. As far as temperatures are concerned, highs will remain above normal through Tuesday with a drop to more normal temperatures thanks to increased cloud cover and more widespread precip (perhaps?) Wednesday onwards.

For those individuals who like to get outside and go hiking, rafting, fishing, etc., please keep an eye on the latest forecast and adjust your plans as needed. Getting out earlier is better, before convection starts.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 1119 AM MDT Sun Jul 19 2026

Showers will develop over the higher terrain favoring the southern mountains this afternoon. Look for storms to diminish after 00Z generally ending by 06Z. These storms will mostly impact TAF sites along and south of I-70. The main threats with convection will be lightning, gusty outflow winds (30-40kts), and brief periods of MVFR in heavy rainfall. Otherwise, expect VFR conditions with light winds across the region.

HYDROLOGY

Issued at 922 AM MDT Sun Jul 19 2026

Anomalous moisture remains entrenched across portions of eastern Utah and western Colorado. Rainfall rates of 1-2 inches per hour will be possible with stronger storms. These rates could lead to flash flooding and debris flows especially over recent burn scars.

Storms over the last few days have helped prime lower levels of the atmosphere and saturate the ground where rain was observed. Several locations across southwest Colorado have reported 0.5 to 1.0 inches of rain within 30 minutes which is more than sufficient to create issues in our steep, rocky terrain. This terrain will further exacerbate areas that are already susceptible to flash flooding. This environment has heightened awareness over recent (or actively burning) fires due to the burnt ground's inability of absorbing moisture under heavy rainfall. As such, we will continue to emphasize the potential for flash flooding and debris flows in this regime. To that end, a Flash Flood Watch has been issued today, Sunday, for portions of the San Juans as they have received heavy rain over the last few days increasing the chances for Flash Flooding there.

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 vulnerable terrain to flash flooding and/or debris flows. Storms across the west develop quickly, leaving little room for lead time in flashy terrain.

GJT WATCHES/WARNINGS/ADVISORIES

CO...Flood Watch until 8 PM MDT this evening for COZ018. UT...None.