Heat dome expected to push temperatures above 100°F across U.S. during July 4 weekend

A broad area of high pressure, described by forecasters as a “heat dome,” is set to bring sustained extreme heat across central and eastern United States this week. Temperatures are projected to climb into the 90s and low 100s, with the Mid-Atlantic and Northeast facing the greatest risk of exceeding 100°F. > "Washington, D.C., will almost certainly exceed 100 on at least one or two days," said Marc Chenard, a meteorologist at the Weather Prediction Center. He added that Philadelphia and New York City are also forecast to top 100°F.

The heat is expected to begin Sunday in parts of the Plains, move into the Great Lakes region and the Gulf Coast by Tuesday, and reach much of the East Coast by Wednesday. High humidity will amplify the heat, and nighttime temperatures are likely to remain unusually warm, with lows staying in the 70s and, in some cities, not dropping below 80°F. Chenard noted that New York City, Philadelphia, Washington, D.C., and even Chicago could experience record-high low temperatures through the middle of the week.

The pattern is projected to persist through the Fourth of July holiday weekend, offering little relief as the high-pressure system remains “pretty persistent,” according to the meteorologist.