Heat invades Spokane and Northwest for next week at least

Summer temperatures are upstaging spring throughout the Northwest.

A string of days with record and near-record warmth is unfolding across the Pacific Northwest and southwest Canada, starting Friday then persisting through the weekend and into early next week. Amid the early-season heat wave, temperatures will reach as high as 20 to 35 degrees above normal in a zone from California to the Arctic Circle.

Temperatures in Spokane are expected to top 80 for the next week, reach the upper 80s on Monday and perhaps hit 90 by Friday, according to the National Weather Service.

Sunny skies are expected until there’s a chance for thunderstorms Monday evening and Tuesday, said Rocco Pelatti, National Weather Service meteorologist in Spokane.

Spokane temperatures in May don’t usually hit 90. But it’s happened 39 times since records started to be kept in 1881, most recently in 2017.

Pelatti said the nighttime lows will approach records most nights, falling only to the upper 50s or lower 60s, about 25 degrees higher than normal.

Melting mountain snow will keep rivers high, but in Washington only the Okanogan River in Tonasket and the Stehekin River in Chelan County are forecasted to reach flood levels.

Locations west of the Cascade Range, including Portland and Seattle, have been placed under a heat advisory for the risk of dangerously high temperatures. Readings should top 90 degrees on several days in Portland and could flirt with 90 degrees in Seattle. Heat advisories also have been hoisted for California’s Central Valley, where highs may pop into the 100s on several occasions.

Seattle is likely to see several daily record highs, beginning as soon as Saturday. A high near 90 degrees on Sunday could threaten the earliest 90-degree or higher temperature on record. The record is May 17 in 2008.

Spokane is only expected to reach 85 on Sunday. (Spokane’s earliest 90-degree on record is April 29, 1926.)

Portland may reach daily records on any day through Monday. Highs there are expected to be above 90 degrees .

Vancouver, British Columbia, could see its earliest 80-degree day on record. The record is May 16 in 2006. The forecast is right around that mark for Sunday and Monday.

Warmer than average weather has been ongoing in northern Canada for some time now, but this flex begins in Nunavut and the Northwest Territories of the country Friday, where locations on Hudson Bay were already approaching record daily highs. A large area of readings around 35 degrees above average is forecast. By Sunday, temperatures 20 to 25 degrees above average stretch from Ontario to British Columbia and southward along the U.S. West Coast.

Jonathan Brunt of The Spokesman-Review contributed to this report.