Pacific Northwest to swelter in "oppressive and unprecedented" heat wave

An "extreme" and dangerous heat wave is expected to begin in the northwestern U.S. on Saturday with the potential to smash multiple records, according to forecasters. Seattle and Portland are among the areas expecting to see all-time highs.

"Oppressive and unprecedented heat will be felt throughout the Pacific Northwest and Northern Great Basin today, with record-breaking temperatures lasting through at least the beginning of next week," the National Weather Service said.

Temperatures are expected to be 20 to 30 degrees above average in Oregon, Washington and northern Idaho this weekend — meaning they could climb into the 110s.

"Dozens of daily record high temperatures will undoubtedly be set, with monthly and even all-time records in jeopardy of falling," forecasters said. "In short, heat of this magnitude has very rarely (if ever) been felt throughout this region, especially this early into the summer season."

Parts of northern California and western Nevada are also expected to see temperatures climb into the triple digits.

"Residents are urged to avoid extended periods of time outdoors, stay hydrated, and check on vulnerable family members/neighbors," the National Weather Service said. "With severe and extreme drought conditions found throughout much of the West, elevated fire concerns exist."

CBS Portland affiliate KOIN is predicting the city will hit 106 on Saturday — and all-time highs of 110 on Sunday and Monday. 

"It has never been as hot in Portland as it will be this weekend," wrote KOIN meteorologist Steve Pierce.