textproduct: Grand Junction

KEY MESSAGES

- Mild fall conditions continue through tomorrow.

- Increasing precipitation chances arrive Friday morning with light rain and snow above 10000 feet.

- Deeper moisture arrives Saturday night and will increase the chances for impactful precipitation for southwest CO Sunday and Monday.

- River flooding seems unlikely, but localized impacts due to rainfall on saturated soils are expected.

DISCUSSION

Issued at 1030 PM MDT Wed Oct 28 2026

Flow aloft is beginning to shift from westerly to southwesterly as an area of low pressure descends along the West Coast. This is beginning to pull high-level moisture into the Southwest, showing up as increasing upper level clouds. This trend of increasing upper level moisture will continue through the day Thursday and into Friday, though the lower levels will remain dry. A wave rotating around the parent low, still stationed off the Pacific Northwest coast, will provide lift to kick off showers that linger through the day Saturday. PWAT values by this point are projected to be over 200% of normal, although dry surface levels will take time to saturate. Precipitation through the day on Saturday will be on the lighter side as a result, with predominately rain showers, with some snow possible above 10k feet. A stray thunderstorm or two will be possible as well, which could produce brief heavier rainfall across the region.

A stronger moisture push associated with an atmospheric river (AR) arrives on Sunday. This AR is expected to take a southern track through Baja California and into the Desert Southwest. There remains a bit of disagreement between model solutions as to just how far south this moisture plume tracks. The ECMWF Ensemble tracks the plume further north, and has higher anomalies, with PWATs expected to be above 300% of normal near the Four Corners on Sunday. The Ensemble GFS is further south and has lower anomalies, with PWATs closer to 250% of normal during the same period. Either way, this is an impressive amount of moisture that, when combined with enhanced lift ahead of the approaching low, will result in widespread precipitation. Models do still agree on an area of 1-2 inches of rainfall across southwest Colorado and southeast Utah Sunday into Monday. River flooding remains unlikely at this point, as these totals will be spread over an almost 48 hour period. What is a bigger concern is flash flooding across areas with still saturated soils from last week's rainfall, particularly for areas of steep terrain, and over recent burn scars. A cold front pushes through from northwest to southeast Sunday night into Monday, with snow levels dropping to around 8000 feet by Monday morning, and close to 7000 feet by the evening as colder air pushes in behind the front. This will bring snow, which could be intense at times, down to pass level. Mountain passes will likely see some travel slowdowns for motorists Monday morning and into the afternoon. Precipitation will taper off Monday night, with colder and drier conditions anticipated for Tuesday and beyond.

Temperatures will steadily cool Thursday onward through the weekend, as clouds and showers overspread the area. Behind the cold front, highs on Monday and Tuesday will run close to 10 degrees below normal, and area expected to remain in this range through much of the rest of the week.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 1132 PM MDT Wed Oct 28 2026

Expect VFR conditions with light terrain driven winds and high scattered clouds through the TAF period.

GJT WATCHES/WARNINGS/ADVISORIES

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