Forecast Highlights:

• Active wildfires burning in California and Utah with periods of smoke expected across these areas throughout the week, along with occasional smoke for Colorado, Wyoming, and Nevada.
• Above-average temperatures for most of the West this week.
• Active monsoon across CO, NM, AZ, and UT with daily thunderstorms, active cloud-to-ground lightning, and locally heavy rain.
• Flash flood risk for slot canyons, dry washes, and burn scars across the Four Corners states throughout the week. 
• Thunderstorms across the Northern Rockies starting Wednesday and continuing through the weekend as monsoon moisture extends northward.
• Mostly dry pattern for the Pacific Northwest though Oregon will see some thunderstorms on Tuesday.

Synopsis:

An area of high pressure is centered near the Four Corners while a ridge is building northward along the West Coast, resulting in hot temperatures across California and Inland portions of the Northwest. At the same time, monsoonal moisture is increasing across New Mexico, Arizona, and Southern Utah. A backdoor cold front (from the northern plains) is also working its way into Southern Colorado and Central New Mexico, which will act as a focal point for thunderstorms on Monday.

The monsoon will continue to intensify across the Four Corners as the week progresses. A weak trough of low pressure will also approach the Northwest later this week, with isolated thunderstorms developing across Oregon on Tuesday and scattered thunderstorms developing across the Northern Rockies from Wednesday on as upper air disturbances associated with the trough interact with increasing monsoonal moisture from the south.

Fire and Smoke Update:

Several large and rapidly growing wildfires started late last week and over the weekend across Central Utah, and smoke has become noticeable across much of the state with downstream smoke extending eastward into Colorado as well. Smoky conditions are also present across parts of California, with the Washburn Fire in Yosemite National Park being the main culprit.

As the week progresses, the heaviest and most widespread smoke will continue to impact California and Utah, while lighter smoke will filter into Nevada, Wyoming, and Colorado at times through the week.

Be sure to check out our Smoke Forecast Map for short-term smoke projections (out to 48 hours) and our Air Quality Forecast Map for smoke projections out to 5 days.

Fire danger is gradually increasing across California, the Great Basin, and the Central Rockies thanks to hotter than average temperatures in recent weeks, which will also continue for the foreseeable future. 

In terms of fire weather conditions, most areas of the West (excluding the Northwest) will be in the "moderate" category this week, with monsoonal moisture and a lack of widespread winds helping matters, while hot temperatures and the potential for dry lightning in some areas not helping matters. 

Forecast for Monday:

Scattered thunderstorms can be expected across Northern Arizona, Southern Utah, Southern Colorado, and New Mexico with dry conditions elsewhere (maybe some isolated storms near the Continental Divide in Wyoming).

A cold front working its way into Southern Colorado and Northern New Mexico will act as a focal point for more widespread thunderstorms and heavier rains across the Southern Front Range, Sangre de Christo Range, and southern/eastern San Juan Range.

There will be a potential for heavy rain and flash flooding in particular across Southern Colorado and Northern New Mexico, especially over burn scars. However, canyon regions of Arizona and Southern Utah will also see a risk for flash flooding.

Forecast for Tuesday:

Monsoonal moisture will spread northward just a bit on Tuesday with a threat for thunderstorms across most mountain regions of the Four Corners states, possibly extending as far north as the Wasatch and Uintas. Canyons, dry washes, and burn scars will continue to see an elevated flash flood risk.

A little bit of moisture will sneak into Oregon as well ahead of an approaching upper air disturbance, and this could result in isolated dry thunderstorms across the Southern Cascades and Blue/Wallowa Mountain. A stray thunderstorm also couldn't be ruled out over the Sierra.

Forecast for Wednesday:

Monsoonal moisture will surge northward into Wyoming, Idaho, and Montana on Wednesday and will interact with an upper air disturbance to produce scattered thunderstorms. Meanwhile, the flow of monsoonal moisture will remain well established across the Four Corners states with another round of thunderstorms expected. Canyon country flash flooding will remain a threat as well.

Outlook for Thursday - Friday:

A similar pattern will remain in place on Thursday with scattered thunderstorms expected throughout the Rockies, with a slight chance existing over the Sierra as well. On Friday, the thunderstorm threat will begin to decrease across the Northern Rockies while the Four Corners states will see another active thunderstorm day.

Outlook for Saturday - Sunday:

An active monsoon pattern will continue across the Four Corners states this weekend, similar to previous days. Also, monsoonal will push northward again into Idaho, Wyoming, and Montana with increasing thunderstorm chances as another disturbance approaches.

As is typical at this time of year, early starts will be key for peak bagging and other high-elevation adventures.

A cold front will also move into the Pacific Northwest this weekend, but it looks to be moisture-starved with nothing more than isolated light showers expected across Western Washington.

Outlook for Monday (7/18) to Monday (7/25):

A ridge of high pressure will remain in place over the Intermountain West next week with above-average warmth expected for most areas. The exception will be near to below-average temperatures across Southern Arizona (thanks to the active monsoon) and also for areas west of the Cascade crest in the Pacific Northwest.

The Four Corners region will remain favored for wetter conditions as an active monsoon pattern continues with drier conditions across the Northwest and Northern Rockies.

Thanks so much for reading! Next update on Wednesday (7/13).

ALAN SMITH