Punishing heat waves peaking in Northwest and Northeast to ease this weekend

Twin heat domes, or high-pressure system, have baked large parts of the country since midweek, setting numerous records. One heat dome on the West Coast was flexing across the Northwest on Friday and is expected to sink south this weekend. The other, centered near the Mid-Atlantic states, was pumping hot air over the central and eastern United States and will also retreat to the south over the weekend.