A dangerous heat wave is tightening its grip on the East Coast, with the worst conditions underway as millions prepare to celebrate the Fourth of July outdoors. Record-breaking heat scorched parts of the Midwest on Wednesday, but the most intense heat shifted into the Interstate 95 corridor Thursday and will persist through Friday. Temperatures both days are forecast to climb into the upper 90s and low 100s from Washington, DC, to Boston, with humidity pushing the heat index above 110 degrees in spots.
Heat Indices Soar Early
Intense heat got off to a fast start Thursday and won’t let up anytime soon. Heat indices had topped 100 degrees by 10 a.m. Thursday in every major metro from Washington, DC, to New York City. By noon, parts of Washington, DC, and Philadelphia hit 110 degrees. Air temperatures also pushed into the triple-digits early Thursday afternoon, including in Philadelphia, Newark, New Jersey, and New York City, and could get hotter in the coming hours.
Record-Breaking Temperatures
New York City’s Central Park reached 100 degrees just before 2 p.m. ET. It’s the first triple-digit reading there since July 2012 and also ties the high temperature record for the day. The timing couldn’t be worse. The heat is peaking during one of the year’s busiest periods of travel and outdoor celebration, prompting cities to expand cooling centers, shorten parade routes and activate emergency response plans ahead of America’s 250th birthday.
Widespread Heat Risk
More than 160 million people are under “major” (Level 3 of 4) or “extreme” (4 of 4) heat risk through the end of the week, according to the National Weather Service. These categories are associated with a sharp increase in heat-related illnesses, especially during prolonged heat waves with little overnight relief. The combination of temperatures and humidity increases the health risks: High humidity keeps temperatures elevated and prevents sweat from evaporating efficiently, making it harder for the body to cool itself.
