Heat Dome Covers More Than Half of U.S. Through July Fourth Weekend

A heat dome is holding more than half the United States under dangerous temperatures through the July Fourth holiday weekend. The National Weather Service said peak heat indexes could reach 115 degrees in some areas, with more than 300 records expected by Saturday.

The heat wave is forecast to peak Friday and Saturday from the Midwest to the East Coast. Overnight lows are not expected to drop low enough to provide relief. Ten states are projected to exceed 100 degrees on Friday.

City tied its record high of 100 degrees on Thursday and could reach triple digits again Friday. The city is deploying vans with nurses and paramedics to distribute water, electrolytes and sunscreen, and to perform wellness checks. Cooling centers are open in all five boroughs.

Philadelphia canceled its Salute to Independence parade. Boston recorded its 29th 100-degree day in city history on Thursday. In Nashville, heat patrols began distributing bottled water to the homeless population. Washington, D.C., issued an extreme heat watch through Friday with a forecast high of 103 degrees.

m. Fireworks displays were canceled or postponed in several surrounding suburbs.

City Mayor Zohran Mamdani warned residents of "extremely dangerous conditions" and advised people to stay inside. m. ET Saturday. "For heat stroke, the differential factor is that altered mental status, that confusion," Dr. Catrina Cropano, medical director of the emergency department at Mount Sinai West, told CBS News.

" Severe storms are expected to shift southward along the I-95 corridor over the weekend.