textproduct: Grand Junction

KEY MESSAGES

- Two rounds of winter weather is on tap tonight through Saturday night favoring the northern and central Colorado mountains.

- The first round will mainly impact the northern Colorado mountains late this evening through tomorrow afternoon. A Winter Weather Advisory is in effect for the Elkhead and Park Mountains beginning at 11 PM. - Round two arrives Friday night with more widespread accumulations and stronger winds at the high elevations. Winter Storm Warnings are in effect for portions of the northern and central Colorado mountains Friday evening through Saturday evening.

SHORT TERM /THROUGH FRIDAY/

Issued at 416 PM MST Thu Dec 4 2025

Our next winter weather system arrives tonight as a shortwave trough accompanied by an increase in moisture moves in from the northwest. PWAT anomalies surge to 150% of normal with its passage with enough lift to support light to moderate snowfall rates mainly centered over the northern Divide mountains. Impacts from this snowfall will be greatest over the Elkhead and Park Mountains where a Winter Weather Advisory is in effect from 11 PM this evening to 5 PM Friday. Hazardous travel is likely over mountain passes during this timeframe from snow- covered roads and reduced visibility. Use caution while driving!

Adjacent high valleys and other area mountain ranges along and north of Interstate 70 will likely see an inch or two of light snow over the next 24 hours. You may encounter winter driving conditions, especially during periods of active snowfall. Drive carefully!

LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/

Issued at 416 PM MST Thu Dec 4 2025

By Friday night heavier snow rates should begin in the northern mountains. The onset of the heavier snowfall is associated with a push of anomalous moisture into the region from the northwest. PWATs 175 to 200% of normal are expected advect across the CWA late Friday through much of Saturday. In addition to the elevated atmospheric moisture, northwesterly flow will support orographic lift, especially in our northern mountains, and disturbances embedded in the flow will provide additional upper level support. As the additional upper level support moves through the area, beginning overnight Friday, the increased snowfall rates will spread down the Divide. The GFS Ens and ECMWF Ens seem to have good agreement run to run on timing and amounts, and timing is similar between these ensembles, but between the ensembles snowfall amounts still differ a bit. Regardless, confidence is high enough to issue Winter Storm Warnings for some of our northern and central mountain zones, in addition to some Winter Weather Advisories as well. Presently, the greatest snowfall rates are expected to occur late Friday night through Saturday morning, but snowfall looks to continue through Saturday night. Hazardous to dangerous travel is possible during this event, so be sure to use caution if traveling. Drier air moves in on Sunday, which should end most snowfall. However, orographic lift from persisting northwesterly flow may allow for continuous light snowfall in the northern mountains. Otherwise, generally quiet weather is in the forecast for the start of next week. High temperatures will fluctuate around normal through most of the weekend, but may warm towards the end of the long term.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 948 PM MST Thu Dec 4 2025

Low stratus is keeping cigs at KDRO below ILS breakpoints. These clouds could linger to sunrise. Elsewhere, look for another round of snow to begin impacting many terminals today. Visibility could drop to IFR or LIFR at KHDN as a result as soon as within the next couple hours. MVFR to IFR visibility could occur at KASE, KEGE, KRIL, and KTEX after sunrise. Cigs will likely fall below ILS breakpoints for all higher elevation terminals as this storm passes through.

GJT WATCHES/WARNINGS/ADVISORIES

CO...Winter Weather Advisory until 5 PM MST Friday for COZ004. Winter Storm Warning from 5 PM Friday to 11 PM MST Saturday for COZ004-013. Winter Weather Advisory from 5 PM Friday to 11 PM MST Saturday for COZ005. Winter Weather Advisory from 11 PM Friday to 11 PM MST Saturday for COZ008-009. Winter Storm Warning from 11 PM Friday to 11 PM MST Saturday for COZ010-012. UT...None.