Big Picture:

A northwest flow pattern will persist east of the Divide in Wyoming and Colorado on Friday and Saturday, resulting in continued active weather with strong to severe thunderstorms. However, a strong ridge of high pressure over the Southwest will gradually work its way north over the course of the week, resulting in a drying trend for much of the West.

Gusty winds from Friday through Sunday along with hot and dry conditions will result in high fire danger across Central/Northern Arizona as well as portions of Southern Utah and Southwest Colorado.

Further north, smoke from Canadian wildfires that impacted the PNW earlier this week will retreat northward this weekend. From this weekend through early next week, smoke will generally be confined to areas of Northern BC and Alberta, barring any new significant fire activity. 

Over the next five days, temperatures will be above average across the Southwest and Interior Northwest, and well above average across Western Canada (where fire danger remains high).

Temperatures will remain on the cooler side of average east of the Divide in Wyoming and Montana, at least through the weekend. Also, temperatures will be cooler across California and coastal portions of Oregon and Washington thanks to onshore winds. 

Forecast for Friday:

Thunderstorm activity will favor areas along and east of the Divide in Wyoming and Colorado. Strong to severe thunderstorms will also be possible east of the Divide and over the adjacent plains across Colorado and Southeast Wyoming, with large hail and damaging straight-line winds posing the greatest threats.

Further north, isolated thunderstorms can be expected across Montana, Idaho, Oregon, and Washington, with more numerous showers and thunderstorms across Western Canada.

Forecast for Saturday:

A similar setup will remain in place with thunderstorms favoring areas east of the Divide in Wyoming and Colorado, while more isolated to scattered thunderstorms can be expected west of the Divide across the Northern Rockies, Eastern Cascades, and Western Canada. Severe thunderstorms will be possible east of the Divide once again.

Forecast for Sunday:

A drying trend is expected for most areas with only some isolated thunderstorms near/just east of the Divide in Colorado and Wyoming, as well as across Western Canada, Washington, and portions of the Northern U.S. Rockies. A few isolated thunderstorms may also sneak into Southern Arizona.

Forecast for Monday to Tuesday:

A stronger disturbance will move across the Northwest early next week, resulting in more numerous showers and thunderstorms across Western Canada, and possibly portions of Northern Washington, Idaho, and Montana with lower confidence on the latter.

Further south, mostly dry conditions are expected aside from some isolated thunderstorms near the Divide in Colorado. 

There are some signs of the North American Monsoon developing in a weakened state across Mexico during this period, with limited amounts of moisture sneaking into Southern Arizona/New Mexico where a few isolated storms with minimal rainfall are possible. 

Outlook for Wednesday (July 12) to Sunday (July 16):

A ridge of high pressure is expected to be the dominant pattern across the West during this period, resulting in mostly dry conditions. However, occasional disturbances tracking along the northern periphery of the ridge could bring occasional showers/thunderstorms to parts of Western Canada and the Far Northern U.S. Rockies.

A weak monsoon is expected to get going across Mexico during this period and some of this moisture may sneak into Southern Arizona/New Mexico from time to time, but only light rainfall is expected with any storms. 

As a result of the high pressure ridge, temperatures are expected to be above average across nearly the entire West, with the only exceptions including areas east of the Divide in Montana, Wyoming, and NE Colorado where near-average temperatures are expected. 

Thanks so much for reading! Next update on Monday (July 10).

Alan Smith