textproduct: Grand Junction

KEY MESSAGES

- Showers, maybe a few storms, move across the area late Friday night into Saturday morning. Some light snow possible at the highest elevations.

- Flooding/flash flooding concerns increase Sunday into Monday, especially for areas that have saturated soils from last week's rain. A Flood Watch remains in effect.

- Winter weather highlights have been issued for the San Juans and central mountains for accumulating snow Sunday morning through Monday evening.

DISCUSSION

Issued at 1227 PM MDT Fri Oct 30 2026

RAIN AND RAINSHOWERS RETURN FOR THE START OF THE WEEKEND:

Broad southwesterly flow continues across the area and as a shortwave trough moves through the region tomorrow, models continue to highlight some showers and storms across the CWA. This southwesterly flow will keep warm temperatures in place so most of this precipitation will fall as rain though a few inches can't be ruled out over the highest terrain of the San Juans. If stronger thunderstorms do develop, brief heavy rain may lead to some very isolated flooding issues but the bigger concern will be the push of moisture on Sunday.

WETTER, UNSETTLED, AND SNOWY SUNDAY AND MONDAY:

A robust Atmospheric River arrives on Sunday bringing well above normal amounts of moisture for this time of year across the desert southwest. Guidance continues to show precip moving into the Four Corners Sunday morning with heavier precip quickly moving in about 3 hours later as the precip spreads northeastward. This on again/off again moderate to heavier precip will continue through early Monday morning before tapering off to more showery type precip. The recent rainfall and flooding from last week is still a concern as we receive anywhere from 2 inches for the Southern Valleys and 3 to close to 4 inches of liquid precip over the San Juans. Flooding remains a concern so the Flood Watch remains in place. More in the Hydrology section below.

The NBM and other models have also been showing temperatures cold enough for some snow accumulation, especially over the San Juans. Despite snow levels increasing through the day Sunday, had enough confidence to issue a Winter Storm Watch for the San Juans for elevations above 10K feet for over a foot of snow and advisories for portions of the central mountains for 5 to 10 inches of snow, also above 10,000 feet. There is still some uncertainty in the forecast though confidence does continue to increase. Either way, please pay attention to the latest forecasts if you'll be travelling this weekend, especially over the higher terrain or the Four Corners region.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1131 AM MDT Fri Oct 30 2026

VFR conditions will highlight the beginning half of the TAF period, before showers and isolated thunderstorms move into the area this afternoon and evening. This shower activity could produce MVFR to IFR conditions at certain terminals. Additionally, it is likely that ceilings will fall below ILS breakpoints at most sites as precipitation propagates through. Winds will be generally light and terrain-driven overnight.

HYDROLOGY

Issued at 1054 AM MDT Thu Oct 29 2026

Low pressure begins to dig southward from the PacNW on Friday, tapping into a fetch of Pacific moisture that will evolve into an atmospheric river streaming into the Desert Southwest this weekend. Showers and thunderstorms will develop Friday and Saturday, but totals will remain on the lower side. However, a few thunderstorms could produce impactful downpours on saturated soils left over from last weekend's historic flooding.

Deeper moisture develops Saturday night into early Sunday. This is expected to produce widespread rainfall with stronger rain rates across southeast Utah and southwest Colorado Sunday and Monday, mostly below 10,000 feet. Some area rivers are currently forecast to go into action stage. Additionally, a growing concern lies in the potential for runoff around steep terrain in the region. This could produce rock, mud, and debris flows onto roadways, as well as flash flood-prone burn scars, washes, slot canyons, and arroyos. Current guidance supports 1 to 3 inches of rainfall for far southeast Utah and portions of southwest Colorado. As a result, a Flood Watch has been issued for 5 AM Sunday through 11 AM Monday.

Outdoor enthusiasts, motorists, and residents of areas recently impacted by flooding are encouraged to remain tuned into the forecast in the coming days.

GJT WATCHES/WARNINGS/ADVISORIES

CO...Winter Weather Advisory from noon Sunday to 6 PM MDT Monday for COZ009-010-012-013.

Winter Storm Watch from Sunday morning through Monday morning for COZ018-019.

Flood Watch from late Saturday night through Monday morning for COZ019-021>023.

UT...Flood Watch from late Saturday night through Monday morning for UTZ022-028-029.