textproduct: Grand Junction

KEY MESSAGES

- Winter Weather Advisories are in effect for much of our mountain zones Tuesday night and Wednesday morning.

- Freeze Watches in effect for northwest Colorado valleys Tuesday and Wednesday night as low temperatures will drop into the mid to low 20s.

- High pressure will return temperatures back above normal late week.

DISCUSSION

Issued at 1248 PM MDT Tue May 5 2026

ISOLATED STORMS TODAY:

A handful of notable storm cells have developed along the Tavaputs, Roan Cliffs, and Uintas this morning. Though convection has weakened since, the 18Z GJT sounding saw ~350 J/kg of CAPE, the potential for a few more bulky cells this afternoon does still exist. Should these stronger storms manifest, a few half-inch hail producers cannot be ruled out, especially along the frontal boundary where CAPE is anticipated to be the strongest. This boundary is stretched across the Yampa River Basin right now, and is expected to hold there until this evening when it'll begin to descend southwards across the remainder of the CWA. A few stronger cells may still be able to persist as the favored region shifts to the I-70 corridor and Grand Valley, though drier mid-levels and weakening CAPE would lean these locations towards more strong outflow winds than hail. Overnight, instability should have weakened, leaving precipitation to be more stratiform.

WINTER RETURNS TO THE REGION:

As a transient shortwave approaches the CWA from the north Wednesday morning, strengthening upper-level dynamics will support enhanced snow rates. In addition, after seeing an increase in QPF yesterday morning, the NBM saw another slight uptick this morning, especially across the San Juans. This has added a couple inches of snow accumulation for our mountain ranges, which has in turn nudged the San Juans over advisory- level totals (4 to 8 inches expected). Impacts are still anticipated to be confined to the passes above 10000 feet, but trends are moving towards a situation where travel will be difficult across most of the San Juans. As for the northern and central Colorado mountains, the messaging remains the same with 5 to 10 inches across the mountains with locally higher amount possible. Be prepared for slick roads if you need to travel through mountain valleys and passes. Showers will gradually taper off Wednesday afternoon up north and by Wednesday evening down south as this system exits the region.

In addition to the snow concerns, cooling temperatures are leading to another round of freeze concerns. Tonight, freeze potential is limited primarily to the northwestern portions of Colorado. Thursday morning though, concerns become more widespread, with some valleys dropping to 20 degrees overnight.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 547 PM MDT Tue May 5 2026

Post frontal low clouds and precipitation is keeping IFR/LIFR conditions in place around KHDN with minimal improvement expected there through the night. As the front drops southward cigs should lower and showers expand to the other TAF sites with ILS to MVFR conditions the most probable outcome withe temporary IFR in the mountain TAF sites. Improvement comes through the afternoon hours but we also introduce the threat of thunderstorms and post frontal gusty winds.

GJT WATCHES/WARNINGS/ADVISORIES

CO...Freeze Warning from midnight tonight to 9 AM MDT Wednesday for COZ001-002. Freeze Watch from late Wednesday night through Thursday morning for COZ001-002-007-008-011-021>023. Winter Weather Advisory until noon MDT Wednesday for COZ004- 010. Winter Weather Advisory until 6 PM MDT Wednesday for COZ012- 018-019. UT...None.