textproduct: Grand Junction

KEY MESSAGES

- Isolated showers and thunderstorms through much of the work week, with the greatest chances occurring on Tuesday.

- Chances for wetting rain remains low, and instead gusty outflow winds and dry lightning pose a threat to new fire starts.

- Temperatures will remain above normal through the forecast with triple digits spreading across the lower desert valleys through late week and weekend period.

DISCUSSION

Issued at 1030 PM MDT Sun Jul 5 2026

MOISTURE INCREASES, DRY THUNDERSTORMS MOST LIKELY:

Cloudier skies today have indicated the arrival of some modest moisture to the region, and according to ensembles, as we have been expecting, this push of moisture continues over the next couple days. PWAT's look to rise as high as 150% of normal, which isn't much, but it is notable given just how dry we have been as of late. The concern remains the same though, being that surface conditions are just too dry for widespread wetting rain.

Monday, moisture will still be increasing, as will the temperatures. CAM's are picking up on instability, but most convective development will be isolated, whether it be showers capable of producing wetting rain or dry thunderstorms. A couple hi-res models are indicating a bulkier storm or two developing in the mid-afternoon hours, though the location is uncertain, and most other models are not on board with this outcome at this time. It is eye-catching though and will be worth monitoring tomorrow afternoon. Elsewhere in the CWA, thunderstorm potential is lower, albeit non-negligible. Some CAM's stretch isolated convection across the Uncompahgre Plateau and into eastern Utah. Though the potential is low, any storm capable of producing lightning strikes will also be capable of igniting new fires due to the widespread critical fuel conditions.

As it stands, Tuesday presents an even more active atmosphere which poses greater chances of wetting rain in some locations and dry thunderstorms in others. Storms will again be focused on the San Juans. Wetting rain potential stands at 40-60% east of Highway 550 above Ouray and around 30-40% elsewhere in the San Juans. Across most other mountain ranges in the CWA, wetting rain potential drops below 45%. All high elevations are forecasted at a 35% or greater chance of lightning though, with chances trending upwards over the past couple forecast runs. This is a combination that indicates heightened dry thunderstorm potential.

Moisture begins to depart on Wednesday, but isolated showers and thunderstorms will remain a possibility mostly over higher elevations through Friday.

HEAT-UP THROUGH THE WEEK:

Throughout the week, broad high pressure will be settled to our south. This is a prime setup for a long, steady warm-up through the week. Through the work week, the region will sit about 5 degrees above normal, placing portions of lower valleys in the triple digits during afternoons. As the aforementioned moisture departs into the weekend and the high builds northwards, we will shoot up to 10 degrees above normal or higher. At this point, look for almost all lower valleys and potentially even into portions of mountain valleys to hit that 100 degree mark.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 549 AM MDT Mon Jul 6 2026

Wildfire smoke will continue to reduce visibility at some locations throughout the next 24 hours, particularly KMTJ which could drop to MVFR/IFR at times overnight. VFR conditions will prevail overall with generally light, terrain driven winds with occasional breezy conditions. There is a chance for showers this afternoon near the SW CO terminals that will be capable of producing gusty outflow winds as well.

FIRE WEATHER

Issued at 1030 PM MDT Sun Jul 5 2026

With modest moisture pushing into the region, we are entering a new fire weather weather pattern, one not dominated by hot, dry, and windy conditions, but instead the threat of dry thunderstorms. Surface conditions have been extremely dry for an extended period by this point, and so the odds of this system noticeably moistening up the low-level atmosphere doesn't appear to pan out according to model guidance. Through Thursday, higher elevations are the only locations anticipated to rise into somewhat moister territory in regards to relative humidity with values generally around 25-30% with higher percents towards the peaks of the San Juans. Otherwise, in valleys, sub-20% afternoon relative humidity prevails. What this means for the region is that moisture is expected to remain in the mid-level atmosphere, prompting showers and thunderstorms with little to no rainfall reaching the ground except over the high terrain. These dry thunderstorms will be capable of new lightning ignitions and producing strong outflow gusts that could impact new and existing wildfires. While most of the region will be at slight risk of dry thunderstorms, the focal point will be around the lower slopes of the San Juans.

Beyond Thursday, moisture drops off, leaving us back in a pattern where both the low- and mid-levels are dry. Though this will exacerbate conditions for any new or existing fires, the saving grace will be weak flow remaining in place region-wide. Without the winds to accompany the drying surface, critical fire weather conditions are anticipated to be avoided for the majority of the region, though localized critical fire weather conditions cannot be ruled out.

GJT WATCHES/WARNINGS/ADVISORIES

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