SPOKANE, Wash.—Record-high heat is forecast in the normally mild-weathered Pacific Northwest this weekend, raising concerns about wildfires and the health of people in a region where many people don’t have air conditioning. City officials in Seattle were opening libraries as cooling centers and crews were being sent to places in Oregon where the risk of wildfires was high. The National Weather Service has issued an excessive heat watch and predicted “dangerously hot” conditions Friday through at least Tuesday. The heat wave will cover portions of Washington, Oregon and Idaho, with temperatures rising to 114 degrees Fahrenheit in places, the agency said. “This will likely be an historic heat wave,” the agency said. “Chances are good that many long standing records will be broken.” Among those might be the record high temperature for Spokane, Washington, of 108 degrees Fahrenheit, set in 1921 and 1968, the Weather Service said. AccuWeather meteorologist Bernie …