textproduct: Grand Junction

KEY MESSAGES

- Terrain-driven showers and thunderstorms and unseasonably warm temperatures continue today.

- A pattern change arrives this weekend bringing another round of tropical moisture to the region bringing flood potential to the region.

- Heavy with totals of 1-3 inches rainfall on the San Juans, Abajo and Uinta Mountains, and surrounding valleys may lead to flooding or flash flooding of small creeks, arroyos, rivers and streams. Debris flows and rockslides are possible on steep canyon/mountain corridors and recent burn scars.

- Severe thunderstorms are possible Sunday into Monday morning capable of producing damaging winds, heavy rain and large hail.

- Expect strong winds 35-50 mph with gusts 50-60 mph Sunday, especially over the higher terrain.

- Another pattern change is possible by the middle of next week with an early season winter storm. Snow accumulation is possible above 10,000 ft with snow possible down to 8,000 ft. Forecast confidence is low at this time.

DISCUSSION

Issued at 1203 PM MDT Fri Oct 9 2026

Models are in good agreement with satellite imagery showing the low descending across British Columbia. They concur with the low pushing into Washington State Saturday morning, but are already showing increasing dispersion in solutions on timing and location among the models and even among the members of the ensembles early in the run. This dispersion is reducing confidence in the details of this weekend system to include the track of the remnants of Rachel as it moves into Utah and Nevada. Stay tuned as the forecast develops, but confidence is high for gusty southwest winds increasing Saturday afternoon as the trough develops over California. H700 winds will be about 30 kts Saturday increasing to close to 50 kts by Sunday afternoon while the H500 winds increase from 35 kts to 60 kts over the same period. Expect winds 35 to 50 mph Sunday afternoon with gust 50 to 60 mph possible especially over the higher terrain. While pwats aren't real impressive through this period at 0.70 to an inch, when put with the winds aloft, the atmospheric river effects are significant with Integrated Water Vapor Transport (IVT) values of 500 to 700 kg/m/s. Expect heavy rain possible on the southwest face of rising terrain across eastern Utah and Eastern Colorado with this strong orographic forcing. Additionally, the left exit region of an 80 kt jet streak moves up over the region Sunday afternoon and night providing upper level dynamics supporting possible severe thunderstorms. The primary threat will be damaging outflow winds in excess of 60 mph. Can't rule out large hail possible, or even a tornado with the upper level convective support and strong shear.

The next system to impact the region is an early season winter storm as the cold-core Pacific Northwest low drops down through the Great basin before lifting to the northeast across the region Tuesday evening and Wednesday. This won't bring a lot of snow to the region, but we will likely see some winter driving conditions on the mountain passes with low visibilities and periods of slick roads. We will likely see snow down to 8,000 ft, but don't expect any accumulation below about 10,000 ft. Stay tuned for updates on this one too.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 529 PM MDT Fri Oct 9 2026

Isolated showers and thunderstorms will be dissipating with sunset then begin to reform tomorrow morning as moisture begins to increase in the moderately strong Southwest flow aloft. These strong winds aloft could lead to pockets of LLWS through tomorrow morning then mixing down gusts in the 25 to 35 mph range through the afternoon tomorrow. Showers and a few thunderstorms will also begin expand after sunrise and become more widespread as we go into tomorrow evening. Gusty outflow winds will be the main concern with VFR and low probability of ILS tomorrow afternoon.

HYDROLOGY

Issued at 1203 PM MDT Fri Oct 9 2026

A strong low pressure system off the Pacific Coast will begin to draw in tropical moisture associated with Topical Storm Rachel this weekend. This strong southerly fetch will draw anomalously high moisture content across the Desert Southwest and into eastern Utah and western Colorado. The chance for widespread precipitation increases Saturday evening into Sunday. Total precipitation forecasts range from 1 to 3 inches across high terrain, with highest amounts favoring the Uintas, Tavaputs and the Southwest San Juan mountains.

Embedded thunderstorms are also possible Sunday afternoon, increasing the threat for flash flooding across vulnerable terrain. While confidence in location and rainfall rates remain low at this time, the potential for rapidly rising rivers, streams, normally dry arroyos and slot canyons are possible Sunday through Monday.

Please follow the evolving forecast, especially if your plans including recreating or commuting across eastern Utah and western Colorado Sunday onward. Also, keep in mind weather potential above your location and upstream, particularly for those who reside below sensitive terrain like recent burn scars.

GJT WATCHES/WARNINGS/ADVISORIES

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