textproduct: Grand Junction

KEY MESSAGES

- Isolated afternoon showers and storms possible along the Divide today.

- Precipitation chances increase through the holiday weekend, with peak coverage expected late Sunday into Monday. Storms may be capable of producing flash flooding.

- Look for mild temperatures near normal to five degrees above normal this weekend, warming to five to ten degrees above normal by late next week.

DISCUSSION

Issued at 141 PM MDT Sat Sep 5 2026

Satellite imagery showed a more zonal component of the mid to upper level winds drawing the moist plume in a more northeasterly direction into eastern Utah and Western Colorado. The 12Z model runs have picked up on this shift moving the Pacific Northwest low farther inland to knock the top off the ridge to the east over the Plains. Look for this shift to direct the moist plume into the Four Corners area and north into the Uncompahgre with pwats around an inch. Like wise, the jet has a stronger zonal component bringing some upper level support to the region late Sunday into Monday. Most guidance hasn't adjusted to this shift, but the HRRR and SREF seems to track on this. Blended in 10-20% of these to get at least isolated showers and thunderstorms into the forecast Sunday afternoon over the higher terrain across the southern and central areas. Convection in this plume of moisture is capably of producing stronger thunderstorms with periods of heavy rain that can lead to flash flooding, especially near recent fire scars and in areas prone to flooding. Due to the poor run-to-run consistency of the models, confidence in the forecast is too low at this point to issue any Watch products at this time. Stay tuned over the next 12 hours for updates as the models come more into line, and stay aware to the weather around you if you're going out.

Beyond Monday, models are in agreement on the high pressure over the Southern Plains working west over the Desert Southwest and into Intermountain West shutting off the monsoonal tap, but guidance keeps afternoon showers and thunderstorms in the forecast over the higher terrain mostly from residual moisture in the area. Temperatures today are running around normal across much of the region to about five degrees above normal across the southern areas. Look for temperatures to warm to about five to ten degrees above normal by the late next week.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1109 AM MDT Sat Sep 5 2026

A few showers/thunderstorms will again pop over the southern and eastern mountains on this afternoon but with limited coverage confidence too low to place in any TAFs attm. VFR prevails the next 24 hours.

GJT WATCHES/WARNINGS/ADVISORIES

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