New Delhi, July 4 -- America's 250th birthday is facing severe disruptions as an intense, climate-change-fueled heat wave upends festivities across the eastern United States.

With dangerous, triple-digit temperatures already forcing major cancellations, including Washington, DC's iconic morning parade, a looming threat of thunderstorms could further dampen Independence Day celebrations.

This weekend's America 250 celebrations face potential disruptions from severe weather. The extreme heat and pervasive humidity across the eastern United States are anticipated to spark thunderstorms in the Mid-Atlantic and Northeast starting Saturday afternoon.

While some of these storms could be severe, delivering damaging wind gusts of 60 mph or more...