textproduct: Grand Junction

KEY MESSAGES

- Unseasonably warm and dry conditions dominate the forecast through the middle of this week.

- While most areas remain unseasonably warm and dry, the northern mountains will see light snow Tuesday and more moderate snow Wednesday afternoon and evening. Periods of light snow showers continue across the northern mountains Thursday and Friday

- Friday night and Saturday will see mountain snow and valley rain showers across the northern and central mountains with snow levels rising above 8,000 feet.

SHORT TERM /THROUGH MONDAY/

Issued at 214 PM MST Sun Dec 14 2025

The weak transient ridge is passing over head with a continued weak deep subsidence inversion across eastern Utah and Western Colorado limiting mixing and keeping winds light and terrain driven through the short term. Thin high clouds today are enough to reduce diurnal heating, but with that, temperatures will still run 15-20 degrees above normal today and tomorrow with only the snow cover mountain valleys cooling to near to five or ten degrees above normal overnight. There are a few somewhat heavier cirrus to the west will advect in overnight that will keep the mountain valley morning lows a few degrees warmer than today. These clouds will push on east tomorrow bringing another day of mostly clear skies and warm sunshine. Monday night will see a few high clouds pass across the northern area as a shortwave passes to the north of the region.

LONG TERM /MONDAY NIGHT THROUGH SUNDAY/

Issued at 214 PM MST Sun Dec 14 2025

Despite mostly zonal flow over the West, a shortwave to our east will shift flow to be slightly more northwesterly Tuesday morning. This will allow for some orographic lift, particularly in the northern mountains, as moisture returns to the region on Tuesday. Tuesday's moisture push looks to be the first of many during the long term forecast period. However, PWATs on Tuesday are forecasted to only be around 150% of normal, and forcing will be limited as it advects through the CWA. So, there's a small chance of precipitation in the northern mountains on Tuesday, but accumulating snow is not expected.

An atmospheric river is expected to bring a stronger push of moisture on Wednesday. PWATs during this second moisture push could exceed 175% of normal. In addition, an increase in disturbances within the mean flow could provide a bit of upper-level support. So, some accumulating snow looks possible in the northern and central mountains beginning Wednesday afternoon. Snowfall may continue in the northern mountains through the rest of the long term, sometimes at heavier rates, as moisture from a potentially stronger atmospheric river and increased synoptic forcing move through the CWA.

The ECMWF Ens and GFS Ens seem to agree with each other pretty well on the timing and strength of moisture, even towards the end of the long term. However, there is still significant differences among the members of each ensemble regarding potential snow totals. Additionally, persisting zonal flow across the West will contribute to well above normal daytime temperatures. This means high temperatures could reach above freezing for all but the highest mountain peaks, leading to uncertainty on snow levels and snow ratios. So, unsettled mountain weather is expected to return periodically through the long term, primarily for the northern Colorado mountains, but confidence in the details remains low.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

Issued at 414 PM MST Sun Dec 14 2025

Not much change over the past several days with SCT-BKN high cloudiness translate through and an overall light wind regime. There is still some small probability of temporary MVFR/IFR conditions at KGUC as ground fog drifts over the airfield. Confidence low of lasting impacts there. Otherwise VFR wins the day.

GJT WATCHES/WARNINGS/ADVISORIES

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