textproduct: Grand Junction

KEY MESSAGES

- Fire weather conditions remain localized today and into early this week. Fuels and surface conditions are still dry though. Obey all fire restrictions.

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

- Isolated showers and thunderstorms return tomorrow, with the greatest chances occurring on Tuesday.

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

DISCUSSION

Issued at 1211 PM MDT Sun Jul 5 2026

High pressure, now centered over the desert Southwest, is continuing to drive a period of hot and dry weather in our area. Although, critical fire weather conditions are only localized through at least Tuesday thanks to calmer winds associated with the high pressure. Atmospheric moisture will remain anomalously low today, which is resulting in widespread single digit relative humidity values this afternoon. Moisture is currently advecting into the West and Southwest, bringing showers and thunderstorms well to our West and our South. Some of this moisture is forecast to make its way into our region beginning tomorrow morning. The bulk of this moisture plume will remain to our west, so our PWAT anomalies are only expected to reach 150% of normal. The very dry surface conditions preceding this moisture will make it difficult for rain to reach the ground, especially during the initial onset of moisture. Consequently, there is a low (around 10%) chance of dry thunderstorms tomorrow and Tuesday. Tomorrow the increased PoPs are over the San Juans, but some high resolution guidance is starting to show increased chances of shower activity north of I-70 late tomorrow evening. Shower and thunderstorm coverage will increase on Tuesday as more moisture moves through, allowing for PoPs over most of our higher terrain, with QPF favoring the San Juans and higher terrain just east of our CWA.

Anomalously dry air moves back in on Wednesday, which expands coverage of critical fire weather conditions, although at this time coverage still appears to be on the localized side. A slightly stronger pressure gradient and increased winds aloft will strengthen gusts on Wednesday and Thursday, but the current forecast keeps winds mostly below or near fire weather thresholds.

Many deterministic models favor high pressure building this weekend, and have the center of this high pressure moving across our CWA as ridging propagates eastward. This means the weather is looking very hot and very dry this weekend. High temperatures on Saturday and Sunday have potential to be the warmest they have been so far this summer. It is too soon to say exactly how this weekend's high temperatures might get, but for the Grand Valley models have consistently been keeping triple digit temperatures in the forecast between runs.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

Issued at 501 PM MDT Sun Jul 5 2026

Wildfire smoke will continue to reduce visibility at some locations throughout the next 24 hours, particularly KMTJ which could drop to MVFR at times overnight. VFR conditions will prevail overall with generally light, terrain driven winds with occasional breezy conditions. Enhanced drainage winds are possible at KMTJ, KGJT and KHDN overnight. There is a chance for showers tomorrow afternoon that are capable of producing gusty outflow winds.

FIRE WEATHER

Issued at 1211 PM MDT Sun Jul 5 2026

Critical fire weather conditions look to remain localized though at least early next week. Mid to late this week climbing temperatures and higher mixing could expand these conditions in some zones and this will continue to monitored daily for trends.

The region sees its first glimpse of notable moisture on tomorrow. The caveat appears to be that the bulk of this moisture lingers in the mid-level atmosphere. The initial push of moisture will creep in from the south early tomorrow morning. Inverted-V atmospheric profiles with relatively moist mid- layers could prompt some pyroconvection over hot spots Monday into Tuesday. Surface moisture lingers into Wednesday and peaks on Tuesday. Unfortunately this doesn't mean a whole lot as most valleys won't get much higher than 20% RH with any soothing RH values reserved for the higher elevations. As such, concerns are increasing that we could be facing another multi-day stretch of dry lightning focused around the slopes of the San Juans, albeit other locations across the CWA are poised for slight chances of thunderstorms as well (<35% chance). This will threaten new lightning ignitions and exacerbated wildfire conditions near virga showers and any gusty outflow winds that they produce.

To leave you off with a bit of good news though, beyond Wednesday spanning at least through the end of the work week, though RH falls off once again, the overarching upper-level pattern does not appear to become conducive to widespread critical fire weather conditions as flow remains on the weaker side. This pattern is relatively well-agreed upon amongst ensembles as well. Increasing heat and dryness will still likely pose some fire weather issues. Stay tuned for future forecast updates in case models begin to trend in another direction.

GJT WATCHES/WARNINGS/ADVISORIES

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