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 with locally heavy rainfall possible. Breezy to windy conditions also possible on Sunday.

- 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 1046 PM MDT Thu Oct 8 2026

UNSEASONABLY WARM WEATHER CONTINUES THROUGH FRIDAY:

High pressure sitting to our west will continue to lead to drier and unseasonably warm conditions through Friday. Daytime heating and instability will lead to some terrain based showers and storms Friday afternoon once again, but weak steering winds and lack of shear will lead to pop and drop variety with gusty winds possible. High temperatures will once again be near records with highs 10 to 15 degrees above normal.

WET THIS WEEKEND:

The big story to watch is the potential moisture increase this weekend with the remnants of Tropical Storm Rachel working through the Desert Southwest. Tropical Storm Rachel currently is sitting well off the coast of the Baja but is forecast to make landfall somewhere near the northern tip of the Baja and SoCal by Sunday morning. A deep low pressure trough descending down the west coast from the Pacific Northwest on Saturday will help steer TS Rachel inland and pull the tropical moisture through the Great Basin in the SW flow from the deepening trough. Models are coming into better agreement on the timing of this deep moisture push with PWAT anomalies increasing to 200-250 percent of normal by Saturday afternoon with the biggest push Saturday night into Sunday as PWAT anomalies climb to near 300 percent of normal with the ECMWF being the wetter of the models compared to the GFS. Given the timing of this moisture push, we could see more abundant cloud cover by Saturday morning. Showers look to develop Saturday morning with scattered coverage by Saturday afternoon. Showers will become widespread by Saturday evening into Sunday. There is some uncertainty with regards to storm type as we could see more stratiform rainfall with embedded thunderstorms given the abundance of moisture and timing with more cloud cover in place. We will have jet support by Sunday so if we see any breaks in the cloud cover, we could see some stronger storms develop, which could lead to heavier rainfall rates and localized flash flooding concerns as well as quick rises along streams and rivers. At this time, it appears like the higher rainfall totals through Sunday are focused across eastern Utah, mainly the eastern Uintas and southwest Colorado over the San Juans and adjacent valleys where 1 to 2 inches of rainfall is possible, but this could change depending on the track of Rachel. We will have a clearer picture once hi- res guidance comes in.

Another concern given the proximity of the jet is stronger winds across eastern Utah and western Colorado Sunday afternoon and especially late in the day on Sunday as models are hinting at a dry slot which could potentially lead to some breaks in the cloud cover and stronger winds mixing down as well as stronger storm potential. Current projections have wind gusts 30 to 50 mph in the realm of possibilities.

COOLER, CONTINUED WET WEATHER NEXT WEEK:

Beyond this weekend, forecast confidence is lower. As the remnants of TS Rachel exit to the northeast, another tropical system, Hurricane Simon, will approach the west-central coast of Mexico and is projected to move inland Sunday into Monday. Whether we get this moisture or not depends on the development and track of the aforementioned deepening trough to our west which looks to carve out a closed upper low over the Great Basin. The combination of this closed low to our west and high pressure over SE Texas continue to steer the moisture from the remnants of Simon well east of our area. Meanwhile, this closed low looks to pack a punch as a stronger jet develops early next week resulting in some breezy afternoons before the low tracks across eastern Utah and western Colorado Tuesday into Wednesday. We can still expect daily showers and storms as moisture and forcing remain present. A cold front associated with this system will cause a notable drop in temperatures and snow levels, leading to increasing chances for mountain snow, especially above 10,000 feet. So this system could lead to some decent snow accumulations in the mountains with high temperatures dropping to 5 to 10 degrees below normal by Wednesday. 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 /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 516 AM MDT Fri Oct 9 2026

VFR conditions will prevail at the terminals today. Winds increase today and will gust to around 20 mph around the region, with a few stronger gusts in favored locales. A few showers could develop on the terrain again today. Coverage will be inconsistent, but could produce some gusty outflow winds and brief cloud cover in adjacent valleys. Cloud cover will be on the increase ahead of the weekend storm system forecasted. Breakpoint ceilings are not expected this TAF period. Precipitation chances will increase around the Four Corners at the conclusion of this period as moisture fills into the region early Saturday.

GJT WATCHES/WARNINGS/ADVISORIES

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