Transcript for Millions of people across the country celebrate the 4th of July in extreme heat
We'll turn now to the dangerous holiday weather. One person killed, several injured by a lightning strike in South Carolina. This lightning strike here part of a severe storm in arcadia, Florida. In Jacksonville, heavy downpour downing a giant tree onto a home. Fortunately, no one was inside at the time. And now a tornado watch, as behead into the night. Here's ABC's senior meteorologist rob Marciano. Reporter: Tonight, it's not just heat, but lightning and severe weather putting millions at risk. At least one person killed after lightning struck a tree outside of Charleston, South Carolina. And watch this terrifying close call near Tampa, Florida. Wow! Reporter: In North Carolina, firefighters there rushing to the scene after a home was hit. I heard another pop and so, I started freaking out. Reporter: The severe weather fueled by extreme heat. Parts of the southeast feeling like 100 degrees or more. Outside of Chicago, in Niles, Illinois, firefighters said it felt like 110 degrees when this man spotted a baby inside a car at a grocery store. He was drenched in his own sweat, so, I unbuckled the seat belt. I picked him up and just ran back inside. Reporter: The child expected to be okay. Child's mother now facing charges. And rob joins us now with the latest forecast. Reporter: Hi, Cecilia. That dangerous heat helped spawn some of the widespread tornado watch includes Colorado Springs. We've had numerous thunderstorms from the Carolinas and Florida. That's where that really steamy air is. Feels like 100 degrees in Tuscaloosa. Over that in New Orleans. And with storms on the wane tonight, there could be fireworks shows that could be affected. Cecilia? Thank you, rob. In Washington tonight, and
This transcript has been automatically generated and may not be 100% accurate.