textproduct: Grand Junction

KEY MESSAGES

- Temperatures will continue to run 10-15 degrees below normal through tomorrow, before a very slow warm up kicks in for the weekend and beyond.

- Mountain snow and valley rain return tonight through Thursday night, with 4-8 inches expected for the southern San Juans, La Sals and Abajos, with lesser amounts further north.

- Unsettled weather continues into the weekend, with a few more rounds of mountain snow.

SHORT TERM /THROUGH THURSDAY NIGHT/

Issued at 306 PM MDT Wed Apr 2 2025

A transient ridge over the area this morning has allowed for increased sunshine, although temperatures remain well below normal thanks to the much colder airmass in place. Highs this afternoon will run a solid 10-15 degrees below normal, with the desert valleys in the low to mid 50s, and the mountain towns reaching the upper 20s to low 30s. Convective rain and snow showers have formed over the terrain this afternoon as moisture aloft increases ahead of the next system. These showers aren't expected to be overly impactful, with any snow accumulations confined to the higher elevations, and those accumulations being up to an inch at best. Lows tonight will once again drop below freezing, necessitating another round of Freeze Warnings for the Grand Valley in Colorado, and the Grand Flat and southeast Utah valleys in Utah. That said, increasing clouds tonight will moderate how cold we get, with lows expected to be more borderline. While these clouds will keep lows warmer tonight, they will keep highs cooler tomorrow, with another day of temperatures running 10-15 degrees below normal.

Clouds and more widespread shower activity will be on the increase this evening as the next wave swings through the base of the longwave trough and up toward the Four Corners. With associated southerly to southwesterly flow aloft, this system will strongly favor the southern half of eastern Utah and western Colorado. The higher elevations will see all snow, with the La Sals, Abajos, and southern San Juans expecting 4-8 inches by Thursday night. The southern valleys will see a mix of rain and snow, with periods of all snow tonight, and a trace to 2 inches possible by Thursday night. Further north, the central mountains are looking at 3-6 inches of snow, and the higher terrain north of I-70 expecting 1-3 inches of snow. Winter Weather Advisories have been issued for the southern San Juans, and for the La Sal and Abajo mountains above 7500 feet.

As the precipitation lifts north, rain and snow will spread across the central and northern valleys through the day Thursday. Some stronger convective showers, and even some thunderstorms, could form during the afternoon hours. The impulse driving this will eject east into the Plains tomorrow night, with shower activity finally starting to taper off. Skies will start to gradually clear Thursday night into Friday, with radiational cooling trying to kick in. Subfreezing lows are in the forecast for the desert valleys once again Friday morning, and may require another round of Freeze warnings in the near future.

LONG TERM /FRIDAY THROUGH WEDNESDAY/

Issued at 306 PM MDT Wed Apr 2 2025

The broad, split trough of low pressure aloft lingers over the West on Friday, then gradually moves east of the forecast area on Saturday. Beneath the col between the northern and southern streams, lingering moisture and instability will lead to scattered to numerous showers, especially over higher terrain during the afternoon. Isolated thunderstorms are possible which will lead to local bursts of heavy snow and gusty outflow winds. This activity decreases Friday night as drying and subsidence arrive on the western flank of the low as the trough axis shifts east of the Continental Divide. However, return flow on the western flank of a cold front sweeping southward along the eastern Colorado plains will regenerate showers over the central Colorado and San Juan Mountains on Saturday. This activity will diminish on Saturday night with only isolated/low end scattered showers lingering over the extreme southeast San Juan Mountains by sunrise Sunday. Drying continues Sunday into Monday as a high pressure ridge develops over the Rockies. Models indicated a low amplitude short wave trough undercuts the ridge on Tuesday bringing the potential for showers. Models in fair agreement so unclear how much coverage and precipitation can be expected.

Temperatures are expected to continue running cooler than normal through Saturday, recovering to near normal Sunday, before the warming trend lifts temperatures to close to 10 degrees above normal on Tuesday.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 1147 PM MDT Wed Apr 2 2025

Aviation conditions will continue to erode towards breakpoint conditions tonight. Snow showers, as well as low ceilings and visibility will begin to impact mountain terminals of southwest Colorado by daybreak. These conditions will spread northward through the morning, reaching KEGE and KASE by mid day. This will continue through this TAF period. Some improvement is expected Thursday evening, as precipitation tapers, but low ceilings will likely hang on the terrain through this TAF period and beyond.

GJT WATCHES/WARNINGS/ADVISORIES

CO...Freeze Warning until 9 AM MDT Thursday for COZ006. Winter Weather Advisory until midnight MDT Thursday night for COZ019. UT...Freeze Warning until 9 AM MDT Thursday for UTZ022-027. Winter Weather Advisory until midnight MDT Thursday night for UTZ028.