Core of blistering heat in Northwest US to shift eastward next week

AccuWeather meteorologists say the pattern will flip from extreme heat to welcome relief for part of the region, while other areas keep baking in triple-digit temperatures.

A weather pattern featuring extreme heat, wildfires and smoke will remain in place across the Northwest for much of the upcoming week, though relief is in store for some, AccuWeather meteorologists say.

"Another extended heat wave will grip the Northwest, which will challenge record highs and keep a high risk for wildfire activity in place," AccuWeather Meteorologist Brandon Buckingham said.

The peak of the heat through Sunday will extend from parts of the Desert Southwest and interior of California northward into Idaho, eastern Oregon and Washington as well as western Canada. Long-standing record highs from the early 1900s could fall in the heat surge.

"One particular hot spot is Boise, Idaho, where daily record highs will be challenged every day through Wednesday," AccuWeather Senior Meteorologist Dan Pydynowski said.

Temperatures in Boise run above the city's higher-elevation counterparts, with a peak mid-summer historical average of 95 degrees Fahrenheit. During this late-July swelter, highs will be 10-15 degrees above the historical average.

The departure from the norm will be even more extreme across western Canada, where late-July historical averages in the 70s will be blown out of the water as temperatures soar into the middle and upper 90s. This includes places such as Edmonton and Calgary, Alberta.

While air conditioning is becoming more common in households across the Northwest and western Canada, there is a large percentage of the population who do not have proper means within their homes to stay cool in episodes of extreme heat. Spending even a few hours per day in an air conditioned space can lessen the risk of heat-related illnesses.

"Staying well-hydrated with plenty of water is a must and is critically important during this stretch of heat," Pydynowski said, adding that outdoor activities should be limited to the morning and evening hours if possible.

The area of high pressure that will be responsible for the sizzling conditions across the Northwest will do more than cause temperatures to soar, Buckingham explained.

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"Smoke and haze can become trapped under the dome of high pressure, resulting in poor air quality at times where the smoke is close to the ground," Buckingham said.

More than two dozen large wildfires were burning in Washington, Oregon, Idaho and Montana as of Saturday, July 20, according to the National Interagency Fire Center, with additional blazes charring thousands of acres in western and central Canada.

Rainfall will be limited through early next week. Conditions will be ripe for dry thunderstorms, or clouds with thunder and lightning but little to no rain, to potentially generate new blazes across Washington, Oregon, Idaho and Montana.

Needed relief on the way

The orientation of the high over the West will shift farther to the east by the middle and latter part of next week, as Pacific storms start to break down the heat across western Canada and the Northwest, Pydynowski said.

Record-breaking temperatures in the 100s are likely to expand into Billings, Montana, from Wednesday to Thursday, compared to the city's late-July historical average of 89. Meanwhile, temperatures closer to the historical average will bring needed refreshment to areas farther west.

"Although temperatures will trend downward, the risk for wildfires may actually increase later next week as dry, gusty winds sweep through the Northwest," Buckingham said.

Across the Southwest, temperatures will be near-record territory for some into midweek before gradually declining to historical averages by next weekend. Daily monsoon thunderstorm activity will continue to bring risks such as damaging wind gusts, flash flooding, lightning strikes and dust storms through much of the upcoming week.

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