textproduct: Grand Junction

KEY MESSAGES

- Generally dry conditions with near-normal temperatures are expected through Monday, although an isolated mountain shower or two is possible.

- A frontal boundary could deliver some additional showers Tuesday and Wednesday next week.

- A warming trend will continue through the week. Triple digits will remain confined to the Four Corners and low desert valleys.

DISCUSSION

Issued at 940 PM MDT Sat Aug 15 2026

Ridging builds in over the Intermountain West Sunday as the Southern Plains high begins drifting westward. As a result, dry air filters in across the region, a trend which continues through Monday night. Precipitation chances will be near-zero, although a low probability (less than 15%) of a stray shower or thunderstorm does remain over the higher terrain the next few days. Temperatures will run near- normal through Monday.

A weak frontal boundary sets up across the Northern Great Basin Tuesday into Wednesday, tightening up the surface pressure gradient across northeast Utah and northwest Colorado. Some gustier winds of 20-30 mph will be possible in this region, although surface relative humidity values will be high enough that critical fire weather conditions are not anticipated. Some extra moisture accompanies this frontal boundary, with PWAT values forecast to be 100-150% of normal across the region, with the best moisture north of I-70. With a combination of orographics and a bit of forcing from the frontal boundary, some isolated to widely scattered showers and thunderstorms will be possible across the higher terrain Tuesday and Wednesday afternoon. Slightly above normal moisture lingers through the end of the work week, leading to lower-end (20-30%) chances of showers or thunderstorms over the higher terrain each afternoon. The main threats with these storms will be gusty outflow winds and lightning, although a brief heavy downpour cannot be ruled out.

High pressure settles over the Four Corners Thursday into Friday, ushering in a drying and warming trend. By the end of the week, high temperatures are expected to run around 10 degrees above normal, with triple digits across the lower desert valleys and the Four Corners. Friday into the weekend, models are indicating a trough moving into the Pacific Northwest will nudge the high eastward once again, returning weak monsoonal flow into the Four Corners.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 513 PM MDT Sat Aug 15 2026

A few light showers will linger through 03z this evening, bringing brief heavy rain and gusty, erratic outflow winds to any terminal that a shower moves through. This could lead to brief drops to MVFR conditions. Otherwise, VFR conditions will prevail with ceilings well above breakpoints. Winds will be generally light and follow terrain driven patterns through 18z tomorrow afternoon, then becoming westerly with gusts up to 20 knots possible.

GJT WATCHES/WARNINGS/ADVISORIES

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