A significant heatwave is impacting over 250 million Americans across at least 36 states, with the Midwest and East Coast facing scorching temperatures and high humidity through the Independence Day holiday weekend.
Heat advisories and excessive heat warnings have been issued across numerous states as a "heat dome" settles over the country, bringing temperatures into the high 90s and triple digits, with heat index values expected to feel well over 100 degrees. "More than 250 million people will be impacted by this heat wave," stated AccuWeather senior meteorologist Carl Erickson. "It’s encompassing entire states."
Peak Heat and Affected Regions
The peak of the heat is anticipated on Thursday and Friday for the East Coast. "Parts of the Southeast will also have uncomfortable and potentially dangerous heat and humidity … but many of those areas are used to dealing with those temperatures," Erickson added. The most intense heat is expected to affect the Ohio Valley, Detroit, Chicago, Cincinnati, Philadelphia, Washington, D.C., New York City, St. Louis, Memphis, and the I-95 corridor extending to Boston. Residents from Missouri to Alabama and Mississippi are also advised to exercise extreme caution.
On Thursday, the heat index was projected to reach dangerous levels, with Philadelphia and Washington, D.C., nearing 111 degrees, Nashville at 110, Detroit at 108, Boston at 106, and Chicago at 102. Friday's forecast showed similar extreme conditions, with temperatures feeling like 108 degrees in New York City, 105 in Boston, 112 in Washington, D.C., and 111 in Memphis.
Shifting Conditions and Thunderstorms
By Sunday and Monday, the focus of the extreme heat and humidity is expected to shift towards the Southeast, with North Carolina potentially experiencing conditions feeling like 107 degrees and Georgia around 105 degrees.
The sweltering conditions are expected to begin easing in the Northeast and Mid-Atlantic by early next week. "The heat wave will break down across the northeast and Mid-Atlantic early next week," Erickson said, noting that New York City could see highs return to the 80s. Heavy thunderstorms are forecasted to move into the Northeast, from New York City to Washington, D.C., starting Friday night and continuing through the holiday weekend, even as the heat and humidity linger. In New York City, Saturday is expected to bring a high of 95 degrees with a 55% chance of rain, and Sunday could reach 90 degrees before storms help bring temperatures down to normal by Monday.
In response to the weather, Mayor Zohran Mamdani declared a heat emergency in New York City, and Governor Kathy Hochul stated that state officials are closely monitoring the situation and the electrical grid.