July 2 (UPI) — As the United States heads into a milestone July 4 holiday this weekend, parts of the Northeast are preparing for hazardous levels of heat and humidity, with a heat index of more than 110 possible in some places.
“‘It’s summer, it’s hot,’ ” the National Weather Service posted on social media this week. “We hear ya, but this is no ordinary heat.”
The NWS said the weekend could include “widespread highs within the mid-90s to low-to-mid-100s.”
“Numerous daily temperature records are possible, while warm overnight lows in the 70s and 80s will provide little relief,” the NWS said.
Major to extreme heat risk conditions will prevail across the Midwest — where temperatures soared mid-week — into the East Coast, with the “extreme” zone centered around portions of the Northeast including New York City, Washington and Philadelphia. About 160 million people are in this zone.
“Extreme” heat conditions are defined by the weather service as “rare and/or long-duration heat with little to no overnight relief.”
The heat index, which combines temperature and humidity readings to show how hot it feels out, could reach 110 to 115. High humidity compounds the health risks from high temperatures, as it prevents sweat from evaporating efficiently, CNN reported.
This comes as the United States prepares for milestone 250th anniversary Independence Day celebrations Saturday. The weekend marks one of the busiest travel and outdoor-activity times of the year, but many local officials have urged people to stay inside in air-conditioning and to check on neighbors, The New York Times reported.
Many cities and smaller municipalities are opening cooling centers and adapting holiday plans. The federal Department of Energy declared an emergency and directed the PJM Interconnections electrical grid in the Mid-Atlantic region to “take action” to avoid power outages, ABC News reported.
“It’s really going to strain the grid,” Ramanan Krishnamoorti, vice president of energy and innovation at the University of Houston, said to ABC News. “I think we’re going to see peak demand that is going to be a record across different geographical areas.”
The heat wave originates from a heat dome, an area of high pressure that holds hot air in place. Europe has also been dealing with a record heat wave recently.