textproduct: Grand Junction

KEY MESSAGES

- Isolated showers and thunderstorms expected over the high terrain Thursday. Main concerns will be gusty outflow winds and lightning.

- Triple-digit temperatures on Thursday and Friday in valleys.

- Precipitation potential increases Friday and into the weekend. Flash flooding will be possible, especially Saturday.

DISCUSSION

Issued at 931 PM MDT Wed Aug 19 2026

A slight lull in the active pattern is expected Thursday as the southwestern CONUS high drifts northwards and settles near the Four Corners. Enough moisture remains trapped underneath this high to keep daily showers along the terrain, but hydrologic concerns will be on the minimal side. Regardless, anybody near areas vulnerable to flash flooding should still remain weather- aware over the next two days should a stray stronger storm develop. Otherwise, the main point of interest as we close out the work week will be the abnormally warm temperatures underneath this high pressure. We hit triple digits in many valley locations Wednesday, and as it stands now, this should again be the case Thursday and Friday. Because of the lingering moisture in the Intermountain West, cloud cover will play a role in just how hot these temperatures will be allowed to get, but regardless, look for highs to remain about 10 degrees above normal until we hit the weekend.

Speaking of the weekend, Saturday marks another ramp-up in wet weather. This comes as the ridge overhead builds, pushing flow south- southwesterly and advecting another shot of potent moisture into the Great Basin. The means the strongest portion of this moisture plume will reside to our west, yet hydro impacts become more probable over our CWA during this period regardless. The extent of those impacts will however hinge on how far eastwards this plume can reach, a detail that is in relatively good agreement between the ECMWF and GFS ensembles. That consensus maintains the plume well into Utah with the more anomalous moisture (PWAT's nearing 200% of normal) only really creeping into the area late Saturday as that moisture rotates around the ridge to our north. It should be enough to elevate flash flood potential for most of the region, especially should morning cloud cover clear enough to support stronger convection, but storm coverage may be more scattered than widespread. Due to the projected placement of this shot of moisture, there's still wiggle room for models to nudge it further into our CWA, so don't count out a more widespread event. As guidance stands now though, the flash flood risk appears more moderate. Hi-res models will reveal much more insight into this system, so stay tuned as we begin to receive this model guidance over the coming days.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 544 PM MDT Wed Aug 19 2026

Isolated and scattered showers and thunderstorms have developed over the high terrain and will continue through sunset with a few drifting over lower elevations. Primary threats are lightning and gusty outflow wind gusts to 35 kts. Conditions should remain above ILS breakpoints with VFR conditions primarily with breezy afternoon winds with gusts 20 to 25 kts. Skies will clear overnight with light, terrain driven winds.

GJT WATCHES/WARNINGS/ADVISORIES

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