textproduct: Grand Junction

KEY MESSAGES

- Hot and mostly dry conditions expected Friday with scattered showers and storms, mainly on the higher terrain of western Colorado and eastern Utah. Localized heavy rainfall and flash flooding over burn scars and susceptible terrain cannot be ruled out.

- Daytime highs will run 5 to 10 degrees above normal on Friday with near to slightly below normal highs this weekend and beyond. - A pattern shift arrives this weekend into the coming week, bringing cooler and wetter conditions to the region.

DISCUSSION

Issued at 1038 PM MDT Thu Aug 27 2026

HOT WITH SCATTERED SHOWERS AND STORMS FRIDAY:

High pressure remains centered south of the Four Corners with overall hot and dry conditions continuing for one more day on Friday. Some remnant moisture remains trapped under the high so this will result in scattered afternoon storms favoring the high terrain. Any flooding concerns over burn scars remains very low and localized as the lower levels are much drier than a few days ago. The gradient will tighten a bit as an upper low pressure system moves into the Pacific Northwest, allowing for breezy afternoon winds especially across northwest Colorado. Relative humidity however will remain borderline for critical fire weather conditions so some localized critical fire weather conditions are possible but overall relative humidity will begin to increase throughout the day as the Pacific Northwest trough pushes inland and allows the high pressure ridge to shift eastward.

COOLER AND WETTER THIS WEEKEND AND BEYOND:

A pattern change is in store, with moisture increasing Friday evening and overnight into Saturday. We could see some nocturnal convection but overall, conditions look to be mostly cloudy by daybreak on Saturday. PWAT anomalies surge upwards towards 150 to 180 percent of normal with the deeper moisture still over the Great Basin towards Nevada and northwest Utah. Storm coverage looks to increase with more widespread precipitation, however the abundant cloud cover could limit more robust convective potential due to limited surface heating. It does look like nocturnal convection is possible as several shortwaves move through this flow and continues into Sunday with better forcing Sunday due to the PacNW trough driving a cold front through the area Sunday afternoon. It will remain active through at least Monday as a robust shortwave passes through behind this trough. The potential for flash flooding and heavy rain will increase this weekend into early next week with this moisture push, especially over burn scars and vulnerable terrain.

Models begin to diverge Tuesday and beyond, decreasing confidence with a slight downturn in moisture and some drier air potentially entering from the west by mid week. Blended model guidance indicates less coverage mid to late week with storms favoring the high terrain although some solutions indicate another moisture push late next week as another low pressure trough moves into the Pacific Northwest and southwest flow over the region heading into Labor Day weekend. The eastern Pacific around the Baja Peninsula also looks to remain active with potential tropical storm activity through the coming week, so we'll also be tracking that to see if we can tap into any of that rich tropical moisture later in the week. Overall despite model differences, it looks like we are shifting towards a cooler, wetter and more active pattern heading into the month of September. Stay tuned!

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 512 AM MDT Fri Aug 28 2026

Mid and high level clouds will be on the increase today with another round of convection firing this afternoon. KTEX and KHDN may see a quick storm this afternoon with lesser chances for KASE, KMTJ and KGUC though they can't be ruled out there either. Aside from convection, some gusty winds are possible reaching 20 to 25kts at times. Despite the clouds and convection, VFR conditions will remain in place.

GJT WATCHES/WARNINGS/ADVISORIES

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