textproduct: Grand Junction

KEY MESSAGES

- Mostly dry and warm conditions prevail through Saturday with a gradual increase in afternoon shower and thunderstorm activity each day.

- Daytime highs remain 5 to 10 degrees above normal through Sunday before a shift to cooler temperatures for next week. - Cool, wet and unsettled pattern sets up Sunday through much of next week as moisture continues to feed into the area.

DISCUSSION

Issued at 1107 AM MDT Fri Sep 11 2026

MOSTLY DRY AND WARM THROUGH SATURDAY:

A weak shortwave is currently moving through the area this morning with isolated shower activity across eastern Utah into northwest Colorado. Lower levels still remain dry so not expecting much rain to reach the ground with gusty winds the primary concern. Hi res guidance is indicating isolated shower and storm activity this afternoon focused over the high terrain with more scattered coverage across the Four Corners. High pressure remains south of the Four Corners through Saturday with some drier air and more isolated coverage of afternoon convection over the high terrain with gusty winds the primary concern. The flow turns southwesterly on Saturday with breezier conditions as a low pressure trough moves into the Pacific Northwest. As this happens, relative humidity will increase enough to negate critical fire weather conditions even though winds increase. Still localized critical fire weather conditions are possible this afternoon and Saturday afternoon. Aside from the isolated shower activity and cloud cover, conditions through Saturday will remain mostly dry and warm with highs 5 to 10 degrees above normal.

COOLER AND WETTER PATTERN SUNDAY INTO NEXT WEEK:

Moisture begins to increase more on Sunday as the Pacific Northwest low moves inland across the PacNW and Intermountain West, with the high pressure ridge shifting east allowing better moisture to advect from the southwest. A surface cold front looks to move through Sunday night so shower activity is expected to pick up late Sunday into Monday with overnight convection possible. This pattern looks to remain in place through much of the coming week with troughiness across the Pacific Northwest and Intermountain West and the high positioned to our southeast across the SE U.S., keeping our CWA in that favorable moist southwesterly flow. We will have a direct tap to this abundant moisture as PWAT anomalies climb up towards 180 to 200 percent of normal late Sunday and remain overhead through at least mid next week. A robust upper level jet will remain parked to our northwest, keeping that dynamic forcing in place even though no well defined shortwaves are seen. So Sunday through at least mid next week will remain unsettled with more widespread coverage of showers with thunderstorms also possible. Temperatures will also cool as a result of the increased moisture by Monday through the coming week with highs dropping closer to normal. This is looking like a cool, wet pattern more reminiscent of fall and wouldn't be surprised to see a dusting of snow at the higher peaks with any overnight precipitation.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1116 AM MDT Fri Sep 11 2026

VFR conditions will prevail through the TAF period. Increasing mid level clouds and periodic afternoon gusts of 25-30 knots highlight today's forecast. An isolated shower or storm cannot be ruled out at the mountain terminals, but the potential is too low to include in the TAFs. Winds overnight will return to generally light and terrain driven. Cloud cover will also clear out overnight, with the return of high clouds to begin Saturday morning.

GJT WATCHES/WARNINGS/ADVISORIES

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