A notable uptick in fire activity has occurred across the Interior Northwest this week, especially across Idaho, Eastern Washington/Oregon, and Western Montana.

Strong winds aloft are transporting this smoke throughout the Great Basin and Northern/Central Rockies as well, leading to worsening visibility and air quality for many areas. Ongoing fires in Northern California and Southern Oregon are contributing to the smoke issues as well.

Check out the satellite image from early Friday afternoon, where numerous smoke plumes from fires can be seen. Clouds over Montana are associated with a passing disturbance that will produce some thunderstorms on Friday afternoon, but not much rain.

Our smoke maps highlight the approximate locations of current fires and projected downstream smoke impacts. Here is the forecast for near-surface smoke for early Friday evening.

Forecast Smoke (surface)

Forecast Smoke (sky)

As of midday Friday, high pressure is centered over the Southwest U.S. while an upper atmospheric disturbance is moving across the Northern Rockies, contributing to the gusty winds across the Great Basin and portions of the Rockies, as well as thunderstorms over Montana. 

The greatest fire danger due to strong winds and low humidity is expected across the Central Rockies, while portions of Montana will see a threat for lightning-triggered fires.

Rain and thunderstorm chances will be limited through the weekend across most of the West as monsoon moisture will largely be suppressed south of the Mexico border. Heading into next week, we'll see a gradual uptick in monsoonal moisture with increasing thunderstorms initially over the Southwest.

Forecast for Friday, July 9th

Most areas will see above-average warmth on Friday afternoon, but Idaho and Montana will see cooler temperatures relative to recent days following the passage of a cold front.

Widely scattered thunderstorms can be expected near and east of the Divide in Montana as well as the Bighorns in Wyoming, but most storms will only produce light rain. Farther south, thunderstorms will be more isolated and will produce little rain across Colorado and the Southwest, as well as the Sierras. 

Forecast for Saturday, July 10th

Hot temperatures will prevail west of the Continental Divide, while a cold front east of the Divide will lead to a nice cool-down for Eastern Wyoming and Eastern Colorado.

An overall quiet day is expected on Saturday with isolated thunderstorm coverage primarily limited to the Colorado Front Range, Sangre de Christo Range, Mongollan Rim, and Sierra Nevada Range. Unfortunately, smoke issues will remain present across the Northern Rockies, on what would otherwise have been a good day for high elevation adventures. 

Forecast for Sunday, July 11th

High pressure will strengthen across the West on Sunday, leading to very hot temperatures and possibly record highs for many areas from California to Montana. Eastern Colorado and New Mexico will remain on the cooler side of average.

New Mexico looks like the only area that will see widespread thunderstorm coverage with wetting rains on Sunday, with only isolated thunderstorms north and west.

Sunday will be a good day for peak-bagging in Colorado with lower (but not entirely absent) thunderstorm chances, provided of course that the smoke stays far enough west and north to not cause issues. Right now, only light smoke is expected for Western Colorado on Sunday, but heavier smoke for Utah and Wyoming.

Forecast for Monday, July 12th

Hot temperatures will continue across the most of the West, including a warm-up for Eastern Colorado and New Mexico. However, another cold front east of the Divide in Montana will lead to cooler temperatures. The blotches of below-average temperatures surrounded by above-average temperatures are due to projected thunderstorms early in the afternoon.

A gradual uptick in monsoonal moisture will begin on Monday, leading to better chances of thunderstorms across Arizona, Southern Utah, and Colorado. However, most of the storms will likely be on the drier side as moisture will only just be starting to increase.

Farther west, the Sierras will continue to see isolated thunderstorms as well. And over the Northern Rockies, an approaching cold front will support isolated thunderstorms near the Continental Divide.

Forecast for Tuesday, July 13th

Above-average warmth will persist for most areas, except for East of the Divide who will see temperatures closer to average. Arizona and New Mexico will also see cooler temperatures in response to increasing monsoonal moisture.

More widespread thunderstorms and wetting rains are expected across the Four Corners region as monsoonal moisture begins to surge northward. The San Juans, Sangre de Christo, and Mongollan Rim look to be the most active. 

Farther north, another disturbance in the atmosphere will lead to an uptick in thunderstorms along and east of the Divide in Montana and Wyoming, with the potential for wetting rains as well.

Outlook for Wed, July 14 - Sun, July 18

Little change is expected to the temperature pattern over the second half of next week, with above-average warmth continuing for most areas. The exceptions will be the Four Corners and Washington/Oregon coast where temperatures will be closer to average.

The good news (for drought and fire danger reasons at least) is that monsoonal moisture will continue to increase across the Four Corners with elevated potential for wetting rains and thunderstorms across Arizona, New Mexico, Colorado, and Southern/Central Utah.

On the flip side, lightning danger will increase significantly for hikers and climbers, as will the potential for flash flooding in vulnerable areas. 

Looking farther out, models are in good agreement and have been consistent in projecting monsoonal moisture to surge far enough north around or after July 20th for increasing thunderstorm and wetting rain potential to reach Wyoming, Idaho, and Montana. While this is still more than 10 days out, good and consistent model agreement adds some degree of confidence.

The Great Basin and Sierras are looking drier late next week, but could also see higher thunderstorm potential return around/after the 20th. 

Thanks so much for reading! Next update on Monday (7/12).

ALAN SMITH