A dangerous heatwave is tightening its grip on the East Coast, and the worst is yet to come as millions prepare to celebrate Independence Day outdoors.
Record heat scorched parts of the Midwest on Wednesday, but the heaviest heat is expected to move to Interstate 95 on Thursday and Friday. Temperatures are expected to climb into the upper 90s to low 100s from Washington, D.C., to Boston, with “feel-like” temperatures of 110 degrees or higher due to humidity.
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The timing couldn’t be worse. The heat is expected to peak during the busiest time of year for travel and outdoor celebrations, prompting cities to expand cooling centers, shorten parade routes and activate emergency response plans ahead of America’s 250th anniversary celebrations.
By the end of this week, more than 160 million people are at either Level 3/4 “severe” or Level 4/4 “Extreme” heat risk, according to the National Weather Service. These categories are associated with spikes in heat-related illnesses, especially during prolonged heat waves that rarely subside overnight.
Experts say heat waves are caused by intense heat domes – stubborn areas of high pressure that trap hot air – and are clearly being intensified by global warming.
Many cities, including Boston, New York, Philadelphia, Washington, D.C., and Raleigh, North Carolina, are opening cooling centers and expanding public resources as the dangerous heat subsides.
The federal government is also preparing for this tension. The Department of Energy issued an emergency order aimed at reducing the risk of power outages by increasing power generation within the PJM interconnector network, which serves much of the Mid-Atlantic region.
Philadelphia declared a heat emergency until Saturday night and shortened the route of its Fourth of July parade. A live broadcast of the pope’s virtual address was moved indoors, and authorities shortened the city’s World Cup fan festival ahead of Saturday’s match between Paraguay and France.
Washington, D.C., has issued a heatwave warning through July 5 and is ramping up cooling centers, hydration stations and emergency medical resources as hundreds of thousands of tourists descend on the nation’s capital for holiday events. Organizers of the National Mall celebration are adding water stations, cooling tents and air-conditioned buses for attendees.
New York City has opened hundreds of cooling centers and equipped mobile medical vans with water, sunscreen and health screenings. More than 2,200 LinkNYC kiosks provide directions to the nearest cooling center.
Dozens of long-standing temperature records will be set Thursday and Friday.
New York City may experience its most oppressive days in decades. If Thursday’s heat index reaches 110 degrees as expected, it will be only three days since record-keeping began in 1943 with such a high heat index. The city is expected to reach consecutive triple digits on Thursday and Friday for the first time since 2011, according to the National Weather Service.
Temperatures in Washington, D.C., are expected to reach 104 degrees on Thursday and 105 degrees on Friday, just shy of the record high of 106 degrees. July 4th in the capital is expected to be the hottest day on record at 102 degrees, beating the old record of 100 degrees set in 1919. The three days from Thursday through Saturday could be the hottest three days in Washington, D.C. since 1930, with daily highs in the low triple digits.
Philadelphia could reach 105 degrees on Thursday, while Boston is expected to exceed 100 degrees on Thursday and reach 104 degrees on Friday.
In eastern Virginia, the weather service said this heatwave could be the most severe in the region since July 2012, which caused more than 10 of the state’s more than 30 heat-related deaths in four states.
The biggest concern isn’t just the heat during the day. Warm, humid nights offer little relief, with temperatures only dipping into the 70s in many areas, but hard to dip below 80 degrees in urban areas. Without cool nights, your body has little chance to recover before a dangerously hot day.
Temperature and humidity increase health risks. High humidity keeps your temperature elevated, which prevents sweat from evaporating efficiently and makes it harder for your body to cool down.
Some relief supplies are expected to begin arriving in parts of the Midwest later this weekend, before gradually spreading to parts of the Northeast. However, much of the South is expected to remain warmer than average next week.
