textproduct: Grand Junction

KEY MESSAGES

- Terrain based showers and thunderstorms continue this afternoon with wetting rains unlikely.

- Showers will shift northward on Thursday with areas north of highway 50 favored.

- Localized critical fire weather conditions favor southeast UT and southwest CO Thursday afternoon.

- Excessive heat watch has been issued for Saturday and Sunday afternoon for near record temperatures in the lower valleys of eastern Utah and western Colorado.

DISCUSSION

Issued at 242 PM MDT Wed Jul 8 2026

Widespread terrain based showers and thunderstorms have developed across the region this afternoon. This morning's Grand Junction sounding would have you believe this to be a robust summer thunderstorm event. Unfortunately, the stingy moisture profile we've been working with this week is still robbing much of this mid level moisture. Observations from storms in southwest Colorado show wetting rains have actually made it to the surface in a few spots. Elsewhere, much lighter values are turning up. Showers and storms will taper towards sunset. A weak upper level disturbance working across the Great Basin beneath a weak jet streak could keep some shower activity alive into late tonight. As these showers decay, some gusty outflow winds are likely to bounce around some valleys. This could fan some wildfires too.

Thursday, that upper level disturbance will reside overhead northeast UT and northwest CO. As a result, afternoon convection will favor the northern half of our CWA down to about highway 50, as drier air invades the column around the Four Corners. With some wetting rains in southwest CO this afternoon, I would expect a couple of showers to get a start on the south shoulders of the San Juans Thursday, despite model hesitancy down there. Broad high pressure begins to lift into the region from the south on Friday. Some high res guidance hints at an isolated shower or two on the northern mountains, but nothing southward. This will begin a buildup of excessively high temperatures this weekend beneath stubborn high pressure parked over the West. An Excessive Heat Watch was issued for all of our lower valleys on Saturday and Sunday to account for widespread triple digit temperatures. Some of the lower desert valleys will approach 108 degrees by Sunday.

Critical fire weather begins to taper Thursday, favoring the Four Corners. Lighter winds beneath the high Friday and beyond will further suppress fire weather conditions. Models begin to hint at some moisture working beneath the high onto the San Juans Sunday. Eyes will continue to focus southward to see if any hope for additional moisture emerges Monday and beyond. Moisture starved and wildfire weary, any sign of rainfall will be greeted with hope on the West Slope this year. For now it looks like those triple digit temperatures will continue to bake the lower valleys next week, unless we get some afternoon showers and thunderstorms to cool things off.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 534 PM MDT Wed Jul 8 2026

Isolated showers and thunderstorms are expected to continue through 06Z. The main impacts will be gusty outflow winds as strong as 35 kts, but minimal to no impacts to vis are expected and cigs should stay above ILS breakpoints. Winds calm overnight before breezy conditions with gusts up to 25 kts re-establish tomorrow afternoon beginning around 18-21Z. VFR conditions are expected to persist at all terminals throughout the TAF period.

GJT WATCHES/WARNINGS/ADVISORIES

CO...Extreme Heat Watch from Saturday afternoon through Sunday evening for COZ001-002-005>008-011-014-020>023. UT...Extreme Heat Watch from Saturday afternoon through Sunday evening for UTZ022-024-027-029.