textproduct: Grand Junction

KEY MESSAGES

- Terrain-driven showers and thunderstorms and unseasonably warm temperatures continue through Friday.

- A pattern change arrives this weekend bringing another round of tropical moisture to the region. Overcast skies and widespread light to moderate rainfall are favored.

- Another pattern change is possible by the middle of next week. Mountain snow chances increase with this system, but forecast confidence is very low at this time.

DISCUSSION

Issued at 1204 PM MDT Thu Oct 8 2026

UNSEASONABLY WARM THROUGH FRIDAY:

High pressure continues to drive the forecast through the end of the work week leading to stagnant conditons across eastern Utah and western Colorado. This means that afternoon temperatures will continue to run 10-15 degrees above normal (near-record values) and isolated terrain-based showers and storms are possible during peak heating hours.

WET WEEKEND AHEAD:

Our focus remains on the incoming pattern change this weekend. At the same time as low pressure builds along the West Coast, Tropical Storm Rachel is expected to approach the coast of northern Baja California and southern California. Locally, this will lead to a sizable surge of tropical moisture across portions of the Desert Southwest, including eastern Utah and western Colorado. As PWATs build towards 250-275% of normal, overcast skies will overtake the region, followed by widespread rainfall favoring locations south of I-70 Saturday evening into Sunday.

The current through is that a bulk of this precipitation will fall in the form of rain at all elevations, with light to moderate stratiform rain rates. Embedded thunderstorms are possible from time to time. Most storms will be of the garden variety, but if stronger storms develop, flooding concerns will increase drastically. We'll have a clearer picture once more hi- res guidance encompasses this timeframe over the next 24 hours. If stronger thunderstorms develop, heavy rain rates could lead to localized flash flooding and quick rises along streams and rivers.

COOLER, CONTINUED WET WEATHER NEXT WEEK:

Forecast confidence is very low beyond the weekend, but we generally expect continued wet weather and a gradual transition towards cooler temperatures. As soon as the main push of remnant moisture from Rachel exits to the northeast, another tropical system (Simon) enters the picture. Over the last 24 hours, inland moisture advection from Simon has trended to the east, away from our local forecast area. However, this track will be largely dependent on the evolution of the aformentioned low pressure system to our west.

If the current forecast holds, low pressure will move across the Great Basin towards the local area by midweek. A cold front associated with this system will cause a notable drop in temperatures and snow levels, leading to increasing chances for snow, especially above 10,000 feet. This is a very fluid forecast and we expect the details to change between now and next week. For now, be aware that rapidly changing weather conditions are possible next week.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1100 AM MDT Thu Oct 8 2026

VFR conditions will prevail at the terminals today. A few showers and storms along with the high terrain are expected this afternoon. Brief ceilings and gusty outflow winds can be expected around showers. However, valley terminals are expected to be free of impacts.

GJT WATCHES/WARNINGS/ADVISORIES

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