Big Picture:

A ridge of high pressure will continue to result in hotter-than-average temperatures across most of the West through the weekend. Monsoonal moisture will retreat southward from Wyoming/Colorado into New Mexico over the weekend before gradually increasing throughout the Four Corners region early next week.

We're also keeping an eye on a trough of low pressure that will move into Southwest Canada early next week, with cooler temperatures and widespread rain showers for BC as well as the WA Cascades. 

Fire and Smoke Outlook:

The Flat Fire in Southwest Oregon remains the most impactful fire in the U.S. with smoke from this fire spreading southward across Coastal California and across portions of Western Oregon.

Fires continue to burn across BC at lower intensities following recent rainfall. Most of the fires are located across Central/Northern BC with the heaviest smoke impacting less populated regions through the weekend.

The Canadian Rockies, Northern U.S. Rockies, and Interior Northwest could see some light smoke/haze from time to time this weekend through early next week.

Forecast for Friday:

Northwest winds and lingering moisture behind a departing shortwave will result in isolated thunderstorms near and east of the Divide in Wyoming and Colorado, with more numerous storms expected across Northern New Mexico.

Any thunderstorms across the remainder of the West will be very isolated and coverage and will produce little to no rain.

Forecast for Saturday:

The focus of moisture will continue to shift southward with scattered thunderstorms expected across New Mexico. Thunderstorm chances will decrease across Colorado with only some isolated storms favoring the higher peaks. 

Forecast for Sunday:

Monsoon moisture will begin to increase further west with a better chance of thunderstorms expected across Arizona, though coverage still looks fairly isolated. There is also a chance we could see some isolated thunderstorms across New Mexico and Southwest Colorado.

Isolated dry thunderstorms could also develop across the Sierra, Great Basin, Utah, and Wyoming.

Forecast for Monday to Tuesday:

The monsoon will start to become more established early next week with scattered afternoon thunderstorms developing across the higher terrain of Arizona, Utah, Colorado, and to a lesser extent New Mexico. Some of this moisture will reach the Northern Rockies as well with isolated thunderstorms possible.

A potent trough of low pressure will also move into the PNW during this period with soaking rains possible across Southern/Central BC along with the potential for moderate rainfall across the Washington Cascades and light rainfall in NW Oregon. 

Outlook for Wednesday (July 26) to Sunday (July 30):

The monsoon will continue to take hold across the Southwest and Colorado Rockies during this period with daily or near-daily afternoon thunderstorms developing over the higher terrain. Rainfall is expected to be "near normal" for most areas by late July standards.

Temperatures will remain hotter than average across most of the West, while the PNW will see more comfortable temperatures in the wake of the early week low pressure trough. 

Thanks so much for reading and have a great weekend! Next update on Monday (July 24).

Alan Smith