Big Picture Weather Pattern:

A strong ridge of high pressure remains over the Western U.S. and will continue to work its way eastward, allowing for anomalous heat to spread into the Rocky Mountain states. 

A little bit of lingering moisture from a low pressure trough in the Central U.S. will contribute to terrain-based afternoon thunderstorms in Colorado and New Mexico during the middle of the week, while richer monsoonal moisture will remain bottled up south of the Mexico border for the time being.

Temperatures:

The core of the heat will continue to expand eastward with triple digit heat coming to places like Salt Lake City, Boise, and eventually Denver.

Salt Lake City is forecast to see highs in the 100s for the next 5 days, and even Park City will see highs well into the 90s from Thursday to Saturday.

5-Day Precipitation Forecast:

Wednesday to Friday will be dry across most of the West except for the higher ranges of Colorado and New Mexico. On Saturday and Sunday, thunderstorm activity will increase over a greater portion of the West as monsoonal moisture returns, though some areas could see dry thunderstorms, which could increase the potential for wildfires.

Fire and Smoke Outlook:

A handful of large fires (10,000+ acres) are burning across the West at this time from Utah to California to Washington. Numerous small to medium-sized fires are also burning throughout the West, some of which could eventually grow into large fires given the ongoing hot and dry conditions. 

Heavy smoke is forecast to remain confined to areas near and immediately downwind of the larger fires over the next couple of days, but skies may become a little hazy at times as very light smoke drifts across the West.

High-Res Smoke (Surface) Forecast for Wednesday PM:

Wildfire and Smoke Tracking Tools:

• Active Fires Map
• Real-Time Air Quality Map
• Smoke High-Res (Surface) Map
• Air Quality Forecast Map

The current hot and dry pattern with low relative humidity will result in increasing fire danger across much of the West as vegetation continues to dry out. 

Fire danger is currently high to very high for much of the Far West, and moderate across the Central Rockies.

In addition to hot and dry conditions, occasional upticks in wind speeds as well as dry thunderstorms (storms that produce cloud-to-ground lightning with very little rain) can also lead to local spikes in fire danger.

Forecast for Wed (Jul 10) to Thu (Jul 11):

Scattered thunderstorms can be expected across the higher ranges of Colorado and New Mexico with local downpours possible. Elsewhere, a few isolated thunderstorms are possible over the higher ranges of Wyoming and Montana (mainly east of the Divide) but little rainfall is expected in these areas.

Temperatures will be well above average for nearly the entire West except for Colorado and New Mexico – but even in these latter areas, temperatures will be trending upward.

Here is a closer look at projected 2-day rain totals for Colorado and New Mexico. Note that measurable rainfall is largely expected to be confined to mountainous terrain, with very little rain for valleys, plains, and towns.

Forecast for Fri (Jul 12) to Sat (Jul 13):

On Friday, isolated to scattered thunderstorm activity will remain confined to the mountain ranges of New Mexico and Colorado, and to a lesser extent ranges along/east of the Divide in Wyoming and Southern Montana.

On Saturday, high pressure will shift far enough east to open the door for monsoonal moisture to arrive from the south, resulting in isolated to scattered terrain-based thunderstorms across Arizona, Southern Utah, and California.

This initial uptick in moisture may result in more dry thunderstorms than wet thunderstorms, leading to increased fire concerns.

Most of the West will be very hot during this period. Areas west of the Cascade Crest in Washington and Oregon will see a cooling trend, though it will still be on the warmer side of average.

Forecast for Sun (Jul 14) to Mon (Jul 15):

Monsoonal moisture will continue to increase across the West, resulting in an uptick in wet thunderstorms (storms that produce meaningful rainfall) at least across the Southwest and Southern Rockies. Temperatures will also start to cool off from the extreme values from prior days.

While the return of moisture will be a welcome sight for the Southwest in many regards, the potential for flash flooding will also return to slot canyons, dry washes, and burn scars, so be aware if you live or recreate in these areas.

The Sierra and Northern Rockies may see a mix of wet and dry thunderstorms – while any rainfall would be welcome, there will also be fire concerns due to an uptick in lightning. 

Outlook for Tue (Jul 16) to Sat (Jul 20):

Next week will be hot, but not as hot as this week. Temperatures will remain above average for most of the West, with the highest anomalies expected across the Northern Rockies.

The monsoon will continue to re-establish itself across the Southwest with Colorado, New Mexico, Southern Wyoming, and eastern portions of Arizona and Utah expected to be most favored for thunderstorms and rainfall.

Thanks so much for reading! Next update on Friday (July 12).

Alan Smith