textproduct: Grand Junction

KEY MESSAGES

- Dry conditions and above normal temperatures hang around for one more day before cooler conditions are ushered in.

- Valley rain and mountain snow returns to the forecast this weekend favoring the southern mountains and adjacent foothills.

- After a quiet start to the week an active weather pattern set up for much of next week.

DISCUSSION

Issued at 1030 PM MST Thu Nov 12 2026

This evening's H500 hand analysis map has a highly amplified ridge over the Rockies...extending through central Canada and across Hudson Bay. The ridge is being flanked by a large digging downstream trough over the East and a pair of upstream cyclones over the EPac approaching the coastline. The ridge will translate to the High Plains tomorrow and br further squeezed between the two troughs but it's influence and the southerly flow ahead of the upstream system will keep another mild day in place. Highs will generally be around 5 to 10 degrees above normal even with mid to high cloudiness drifting through.

COOLER, WETTER CHANGE HEADING INTO THE WEEKEND:

Water vapor shows a lead system being kicked toward the Baja this evening by a much stronger cyclone dropping out of the Gulf of AK. A weak AR associated with this southern system will allow the first influx of moisture to be pulled across the 4 Corners on southerly flow as early as tomorrow morning...though the bulk of it will be remain well to the South. This moisture will be more of a primer for a stronger push of moisture moving in tomorrow night. A moderate AR is associated with the northern cyclone which will be impinging upon the Sierras through much of tomorrow as it drops southward. As it drops across the southern flank of the upstream terrain IVT suggests we get a more robust push of moisture into our eastern and southern CWA by late tomorrow evening. Don't expect much in accumulating precipitation until this secondary moisture arrives though some high elevation orographics snow showers and sprinkles in the lower elevations could be possible by sunset. Luckily this system is not brining the highly anomalous moisture as the past few and even though it drops in negatively tilted...will be short lived. Though not overly cold much of the precipitation above 8500-9000 feet should locked in as snow. The persistent moist southerly flow will allow the southern San Juans to once again catch the best precipitation for the event. Other ranges will do better Saturday morning and early afternoon as the front passes through and the overall dynamics aloft are the strongest. Snow levels hover around 9K before fropa then drop to mountain bases by sunset as the storm is exiting. Storm totals of 4-10 inches are most likely over the southern San Juans above 9K with ensemble spot forecasts suggesting higher amounts near a foot in a few favored locations. A bigger challenge is forecasting possible impacts as much of the snow should melt as it hits the roadways during the daylight hours...leaving only a few hours of slushy/snowpacked roads near sunrise on Saturday and over the northern passes after sunset before the system exits. For now will continue to hold off on any winter highlights with other mountain locations only seeing a few inches at best. The liquid precipitation forecast across the lower elevation basins of the San Juan River remain in the quarter to half inch range as the highest probability outcome and hydrographs show only minimal responses at this point.

LOOKING AHEAD:

A cooler and drier Sunday leads to a warmer Monday as ridging once again translates by as a stronger trough digs back upstream. The passage of this trough will brings another round of valley rain and mountain snow by mid week. IVT forecasts suggest a more robust push of moisture and QPF amounts increase as a result. Unsettled conditions persist into the end of the week as low pressure looks to take over much of the West. Forecast confidence is very low at this time due to differences in the timing, strength, and track of this late week system.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1030 PM MST Thu Nov 12 2026

High clouds will begin to move into the region overnight into Friday morning. Moisture will increase Friday night leading to lowering cigs. Regardless, VFR conditions are expected for Friday with conditions beginning to change towards Saturday.

GJT WATCHES/WARNINGS/ADVISORIES

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