Big Picture:

A strong ridge of high pressure building in from the south is drying out the atmosphere across the Central, Northern, & Eastern Rockies where thunderstorms have been most common in recent weeks. Shortwaves passing north of the ridge will bring more numerous thunderstorms to BC and Alberta this week, and also Northern Washington, Idaho, & Montana on Monday.

Further south, the North American Monsoon is beginning to ramp up across Mexico, albeit in a weakened state. A little bit of monsoonal moisture will sneak into the Southwest (especially Arizona) this week, but the result will generally be isolated thunderstorms with light rain and gusty winds, while extreme heat will be the dominant weather feature across this region.

Fire and Smoke Outlook:

While Western Canada will be the favored location for afternoon rounds of scattered showers and thunderstorms this week, this is also the hot spot for wildfires and smoke right now.

Fire activity has picked up across Central and Northern BC and Northern Alberta over the past week, and smoke from these fires will impact portions of Interior BC and the Canadian Rockies (Banff, Jasper, etc.) to varying degrees over the course of the week.

Smoke could potentially sneak into northern and eastern portions of Glacier National Park in Montana later this week as well, though most of the smoke will miss the U.S. Rockies to the east and will impact the Northern Plains instead.

Track Wildfire Smoke & Air Quality With These Forecast Maps

Forecast for Monday Afternoon to Monday Night:

A shortwave moving into the Northwest is favoring and will continue to favor the Central/Eastern Cascades of Washington, Northern Idaho, Western Montana, Interior BC, and Alberta for showers and thunderstorms. Storms across the Cascades, as well as Western Canada, could produce locally heavy rainfall with a threat of isolated flash flooding.

Further south, only isolated showers and thunderstorms can be expected at best over the Central and Southern Rockies.

Forecast for Tuesday:

Thunderstorm activity will favor areas north of the border across Eastern BC and Western Alberta with locally heavy rain possible under stronger storms. A few isolated storms are also possible across the Northern WA Cascades and Far Northern Idaho/Montana.

Further south, a little bit of monsoonal moisture will sneak into Arizona, New Mexico, and possibly Southern Utah/Southwest Colorado where isolated thunderstorms can be expected. Strong wind gusts and cloud-to-ground lightning will be the main threats, with most storms only producing light rain.

Forecast for Wednesday:

Another shortwave will move across the PNW and Western Canada with a few showers/thunderstorms possible over the Olympics and North Cascades, while most of the action is expected across Southern BC and Western Alberta where locally heavy rain is possible.

Across the Southwest, isolated thunderstorms will be possible across portions of Arizona and New Mexico, while just enough moisture will sneak into Southern Colorado for a chance of isolated thunderstorms.

Forecast for Thursday to Friday:

Shortwaves will move across Western Canada and will slide down the eastern side of the U.S. Rockies. Showers and thunderstorms will favor Southern BC, while heavy rain will be possible across the Alberta Rockies. 

Further south, storms will be more isolated in coverage and will generally exist east of the Divide in Montana and Wyoming, possibly sliding into Colorado as well. Across the Southwest, monsoonal moisture will be shunted further south and east during this period, with isolated storms confined to Southeast Arizona and Southern New Mexico.  

Outlook for Saturday (July 15) to Thursday (July 20):

High pressure will strengthen across the West during this period, resulting in a dry pattern for most areas. Southern Arizona is expected to see "near normal" precipitation as fringe-level monsoon moisture is expected for this region, though the monsoon continues to look weak overall during this period. 

The big story this weekend and early next week will be the heat. Many areas across the Southwest extending into the Great Basin and Interior California are already under Excessive Heat Watches for this weekend as temperatures will be well above average.

The only area out West not expected to see above-average warmth is the Puget Sound region and the Olympic Peninsula of Washington.

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

Alan Smith