textproduct: Grand Junction

KEY MESSAGES

- Monsoonal moisture will cause precipitation chances to become more widespread Saturday.

- Heavier rainfall Saturday could lead to localized flash flooding over burn scars and susceptible terrain.

- Temperatures gradually cool off for the weekend and into next week but still remains above normal.

DISCUSSION

Issued at 1014 PM MDT Fri Aug 21 2026

COOLER & WETTER WEATHER THIS WEEKEND:

High pressure will continue to be centered over our region through the weekend. Clockwise flow around this system will favor moisture advection into our CWA. Hence, precipitation chances will become more widespread Saturday under dominant southwesterly flow. Deterministic models are hinting at PWATs at 150-180% of normal during this time period. Storms are expected to favor the higher terrain initially, but adjacent valleys could also get in on the action as storms begin to move off the terrain. Models also seem to be hinting at a shortwave disturbing the driving flow Saturday, which would mean additional lift in an already saturated environment. This will subsequently increase flash flooding and debris flow concerns. Continue to be weather aware and have multiple ways to receive watches and warnings.

Afternoon storm chances will be around Sunday as well while the increased atmospheric moisture remains in place. However, storm chances will be mostly confined to the higher terrain as no additional lift is anticipated from synoptic forcing. With that being said, flash flooding and debris flow concerns persist through at least Sunday as localized heavy rainfall remains a possibility.

Daytime highs cool by about 5 degrees for the weekend, but still remain above normal for this time of year.

NEXT WEEK:

The environment continues to be saturated into next week which will keep afternoon thunderstorms in the forecast daily for the higher terrain. It is unclear how precipitation chances will pan out for the lower valleys at the moment. As more HiRes guidance becomes available, we will likely have a better grasp on what's to come.

Daytime highs hold steady as we move into next week with most locations seeing similar temperatures as the weekend. These values will still be above normal but not quite into record breaking territory anymore.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 426 AM MDT Sat Aug 22 2026

Isolated showers continue to move north across eastern Utah. Isolated to scattered showers will increase across the region through the late morning with the higher terrain seeing more widespread showers and thunderstorms developing around 18Z. Some of the storms will move off the terrain over the lower valleys through the afternoon with most TAF sites seeing some impacts. Lightning, gusts to 45 kts and brief heavy rain producing MVFR ceilings and visibilities will be the primary threats from these storms. Otherwise, outside of the storms, expect VFR conditions through the TAF period with generally light terrain driven winds.

GJT WATCHES/WARNINGS/ADVISORIES

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