textproduct: Grand Junction

KEY MESSAGES

- Snow showers are possible today and Wednesday in the northern Colorado mountains. The probability of 6+ inches of snow is around 60 percent across the high peaks of the Park Range with this system. - A general warming trend is expected, but the snow covered mountains valleys will see cold inversions set up overnight lasting through the days.

SHORT TERM /THROUGH WEDNESDAY NIGHT/

Issued at 338 AM MST Tue Dec 9 2025

Satellite imagery shows the atmospheric river (AR) impacting the Pacific Northwest extending west across the North Pacific to Midway Atoll driven by the ridging over the Eastern Pacific well off the California-Baja Coast and a low pressure system south of the Aleutian Islands. The extent of this AR concurs with the forecast that it will continue through the coming weekend. Models have generally been in good agreement with the Eastern Pacific High building east enough to push the AR remnants north out of the eastern Utah-Western Colorado region shutting down the snow showers across the north late Wednesday onward, but, with the latest model runs, they are suggesting the shortwave trough descending through the Pacific Northwest will brush the northern Colorado mountains late this afternoon into early tomorrow morning pulling the AR moisture far enough south to impact the higher elevations of the Park mountains. The nose of a jetstreak is supporting the shortwave with upper-level dynamics lending more credence to the forecast, but the stronger dynamics stay more to the north and east. The airmass also remains a very temperate with snow levels 7500ft to 8500ft. Look for the snow to fall between about noon today and noon tomorrow with the heaviest snow in the overnight hours. Considered an advisory for Zone 4, but held off since it's only limited to the higher Park Mountains, and areas of travel like Rabbit Ears Pass, the Elkhead and Gore Mountains, will see minimal if any impacts. Temperatures today will run 8-12 degrees above normal, and will warm yet a few degrees tomorrow.

LONG TERM /THURSDAY THROUGH MONDAY/

Issued at 114 PM MST Mon Dec 8 2025

Upper level ridging drives the extended forecast. Late in the week high pressure will build over the Intermountain West leading to warming temperatures and little, if any, chance for precipitation Thursday through Sunday. If the forecast holds as is, much of the area will see multiple days of high temperatures 15-20 degrees above normal for mid-December.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 432 AM MST Tue Dec 9 2025

Currently high clouds are moving in across the region with mid level clouds intruding into northern Colorado. Look for lower clouds and showers at KHDN and the northern Colorado mountains after 18Z with snow levels starting at about 7500 ft, rising to 8500 ft by 12Z. Expect MVFR conditions at KHDN with passing showers. Stronger winds aloft across the northern areas will generate areas of Low-Level Wind Shear (LLWS) in the mountains from KASE north with some gusty west to northwest winds mixing down to the surface on the eastern slope of higher terrain.

GJT WATCHES/WARNINGS/ADVISORIES

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