On July 4th, a severe heat wave, which saw Washington D.C. reach a record 102 degrees Fahrenheit, its hottest July 4th ever, sparked widespread severe thunderstorms across a large portion of the US. Over 75 million people were in the threat zone for severe storms stretching from the Plains to the Northeast, with damaging wind gusts being the primary concern. In Washington D.C., the National Mall was evacuated due to severe weather, and the National Independence Day Parade was canceled due to extreme heat with heat index values expected to reach between 110 and 115 degrees Fahrenheit.
The extreme weather and heat led to significant power outages, with nearly 800,000 customers initially without power across multiple states in the Midwest and Northeast. This number later fluctuated, with PowerOutage.us reporting approximately 795,000 customers without electricity nationwide as of 4:30 PM ET. The extreme heat also strained power grids, with PJM, a major US power grid operator, ordering emergency conservation measures due to generator outages, overloaded transmission lines, and surging air-conditioning demand.
Cities like Chicago, D.C., Philadelphia, and New York City were under severe thunderstorm watches, with some warnings for destructive storms capable of 80 mph gusts and hail. The severe weather threat was expected to linger for parts of the mid-Atlantic on Sunday, with cities such as Richmond, D.C., Baltimore, and Philadelphia still in the threat zone. Despite dangerous conditions, some relief was anticipated, with high temperatures in New York City expected to be in the upper 80s and Boston in the mid-70s on Sunday, a significant improvement from the previous days.
