Portland Sweltered With Hottest Day and Sunday Will Be Worse

Portland posted its hottest day in history on Saturday, and Sunday will be even warmer as a heat wave continues to bring oppressive temperatures across the normally mild Pacific Northwest.

Highs in the Oregon city reached 108 degrees Fahrenheit (42 Celsius) on Saturday and may reach 112F or higher, said Dan Petersen, a senior branch forecaster at the U.S. Weather Prediction Center. To the north, Seattle set a record for the date of 99F at the National Weather Service forecast office and 102F at Seattle-Tacoma International Airport.

In all, 23 records were set around the Pacific Northwest on Saturday, and that will continue through the week in many areas. Spokane, in eastern Washington, is forecast to set “a daily record for every day for seven days in a row,” Petersen said.

“They will still be flirting with setting multiple records in eastern Washington and Oregon, and in Idaho and Montana, all the way through Saturday,” Petersen said.

Counties across the region have opened cooling centers to help residents beat the heat in an area with fewer air conditioners per capita than the rest of the U.S. More than 600 people die per year due to heat related illnesses, according to the Centers for Disease Control and Prevention.

Excessive heat warnings and heat advisories stretch across seven Western states from Washington to Arizona. Heat warnings also cover a large part of western Canada, extending up the Mackenzie River in the Northwest Territories near the Arctic Circle, according to Environment Canada.

The warmth is building under a so-called heat dome that may have been exacerbated by climate change. It’s similar to the pattern that led to a California heat wave earlier this month, said Jeff Masters, a meteorologist with Yale Climate Connections. Kinks in the jet stream have pinned summer weather in place, leading to prolonged heat waves and drought, plus storms and flooding elsewhere.

“The unusual waviness of the jet stream was associated with a pattern we have been seeing more often in summer, which has been connected to human-caused climate change,” Masters said.

When these large high pressure systems get stuck, low pressure tends to form downstream. That led to heavy rains across the central U.S. that flooded highways in Chicago and Detroit on Saturday. Flood warnings are posted from New Mexico to Missouri.

“One pulse reinforces and leads to the other,” Petersen said. “It is the domino effect of this persistent ridge out West.”

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