Unrelenting heat to prolong poor air quality over northwestern US into next week

By Renee Duff, AccuWeather meteorologist

August 5,2017, 6:14:27AM,EDT

 

 The persistent hot and hazy conditions over the northwestern United States will be a dangerous combination for residents and visitors into next week.

The heat has throttled back slightly since its peak around the middle of this past week, but temperatures are projected to remain 10 to 15 degrees Fahrenheit above early August normals through much of this week.
The high temperature in Portland, Oregon, has not been below 90 since July 30 and may not drop below this mark until late next week. Temperatures will approach the century mark once again around Tuesday and Wednesday after dropping slightly over the weekend.

Seattle will once again climb into the lower 90s on multiple afternoons during the first half of the week, following a dip into the upper 80s to start the weekend. Daily record highs will be approached on Sunday and Monday.
Temperatures in interior hot spots will return to the 100s.
The unseasonable heat, combined with poor air quality, will continue to put a strain on those who venture outdoors. Even typically healthy groups may need to limit the amount of strenuous activity outside.
Children, the elderly and those with respiratory issues may need to limit outdoor time altogether.
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“A persistent area of high pressure over the western half of the country will promote stagnant air through much of the week in the Pacific Northwest,” AccuWeather Meteorologist Faith Eherts said.
The sprawling high pressure system has allowed large amounts of smoke from wildfires in western Canada and locally to remain trapped near the ground and cloud the sky for days in the Pacific Northwest.
Air quality will fluctuate in severity as localized winds shift around the core of the smoke and haze through the week.

Cyclists peddle in view of downtown Seattle, cloaked in a haze of smoke from fires raging in British Columbia that swept down into the Puget Sound region, Thursday, Aug. 3, 2017, in Seattle. (AP Photo/Elaine Thompson)

As of Saturday morning, Aug. 5, approximately 30 wildfires were burning across the three-state area of Idaho, Oregon and Washington, according to the Wildfire Incident Information System. Dozens more large wildfires are raging across British Columbia.
An uptick in mainly dry thunderstorms over the northern Rockies and Cascades next week may only raise the risk of lightning-induced wildfires as opposed to dousing ongoing blazes.
However, significant relief is on the horizon.
A strong push of cooler, more seasonable air is projected to arrive around the middle of August, which will sweep away the stagnant air, greatly lower the risk of new blazes and potentially bring meaningful rainfall to the region.