textproduct: Grand Junction

KEY MESSAGES

- Flooding is ongoing across portions of southeast Utah and southwest Colorado, and is expected to continue through Saturday.

- Many rivers will experience their crest Friday or Saturday.

- Isolated to scattered showers and storms are expected Friday and Saturday. They will be capable of producing moderate to heavy rainfall that could result in additional flooding.

- A few storms may be capable of producing strong winds and large hail Friday and Saturday afternoon.

DISCUSSION

Issued at 956 AM MDT Fri Oct 23 2026

ONGOING FLOODING

The main low pressure responsible for all of the recent rainfall is currently located over Nevada and California. This has kept us in southwest flow aloft. Most of the deep tropical moisture has pushed east of the area with the exception of south central Colorado. This is where isolated to scattered showers and storms will be possible mainly this afternoon. These showers will be capable of producing strong winds, hail and heavy rainfall. The main concern is more rainfall for this region, which is already experience flooding. Given the ground is very saturated it might not take much more rainfall to cause additional flooding. Tonight and tomorrow the low pressure begins to approach from southern California. As that happens it will draw moisture back into the area. Therefore we will see an uptick in showers and storms starting tonight and continuing tomorrow. The coverage during this time frame expands to locations mainly along and south of I-70. This means additional rainfall for places that have already experienced excessive rainfall. The rainfall amounts through Sunday are expected to range from 0.5-1.0 inches along the highway 160 corridor with slightly higher amounts in the mountains and lower amounts outside of southwest Colorado. Training storms could result in 1-3 inches, which could result in more flooding and a continuation of ongoing flooding. The low pressure lifts overhead on Sunday so expect more showers across the area. However these showers should be relatively light compared to the past few days. Conditions dry out on Monday as the low pressure lifts out over the Plains.

As we move towards next week, models are also in fairly good agreement that dry zonal flow will begin to propagate the region by Monday. Because of this, we will be seeing cooler than normal temperatures, with the potential for overnight lows to drop below freezing for a couple hours at a time. Keep in mind, this is still relatively far out, so confidence remains low on this matter.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1138 PM MDT Thu Oct 22 2026

Rainshowers and a few storms continue at this hour though coverage is much less than seen earlier. VFR to MVFR conditions will continue through 12z for most TAF sites due to lower cigs and occasional drops in vis under the stronger showers/storms. After 12z conditions are expected to improve, with a marked improvement noted after 18z. Expect some gusty winds in the afternoon of 20 to 25kts as clearing skies allow mixing of higher winds aloft.

HYDROLOGY

Issued at 956 AM MDT Fri Oct 23 2026

Hydrologic concerns remain elevated through Saturday due to the widespread excessive rainfall. Some locations in the southern San Juan mountains have received 3-6 inches of rain since Wednesday afternoon. Potential hazards through Saturday include localized flash flooding from thunderstorms producing heavy rainfall rates and river flooding due to a prolonged period of widespread moderate to heavy rainfall. Several river gauges are near or past crest, but a few downstream locations are not expected to reach crest until tomorrow.

There is a slight and marginal risk of excessive rainfall today and tomorrow in and around the San Juans. Precipitation amounts of 1-2 inches will be possible through tomorrow. An additional concern is of rain on snow leading to more runoff making it into the waterways. Snow levels are forecast around 11-13 kft, which will likely result in melting of some of the existing early- season snow pack. The combined runoff from rain and rain-on- snow will result in a rapid rise in many of our creeks, streams and rivers. If heavy rainfall occurs many of the streams and rivers could experience additional crests.

GJT WATCHES/WARNINGS/ADVISORIES

CO...Flood Watch through Sunday morning for COZ017>023. UT...Flood Watch through Sunday morning for UTZ022-027>029.