Transcript of Severe weather alert on East Coast

Five millions along the East Coast are on alert for severe weather. It comes as Americans gear up for the holiday week in one of the busiest travel times of the year. The TSA predicting that it will break its all-time daily record in the coming days. Friday was already the fourth busiest day in the agency's history. The threat tonight impacting more than 61 million Americans from North Carolina to Maine. Severe thunderstorms, flooding, and tornadoes, all possible, fueled by hot and humid conditions. Out West, days of heavy rain leading to flash flooding in the Albuquerque area. A flash flood warning is in effect into this evening. Our weather team is standing by with the forecast. And ABC's Faith Aboubeh leads us off from the Atlanta airport.

Tonight, amid record-breaking holiday travel, more than 61 million Americans under severe thunderstorm watches from North Carolina to Maine. The system already bringing heavy rains and damaging winds to the Midwest. These lightning strikes in Garnet, Kansas, causing a transformer to explode. Torrential rains leading to dangerous flooding in downtown Albuquerque overnight, prompting water rescues, a city bus among the stranded vehicles.

Last night was very, very extreme when it comes to weather. The convention center was about six inches away from a major extremely expensive flood damage.

Officials say several buildings were damaged, including City Hall and the Police Department headquarters. The severe weather threatening to disrupt their record travel taking place around the July fourth holiday.

It was really busy in Phoenix.

We did have to get there early. Triple A estimating more than 70 million Americans will travel over the holiday period, an 8% increase over 2019, expected to be the busiest fourth of July on record. Some passengers at Atlanta's Hartfield Jackson Airport telling us that weather has upended their travel plans.

Unfortunately, our layover got canceled because of the weather in New Jersey. My flight has been canceled due to the weather there, they say. I'm a little frustrated not knowing where I'm I'm going to go if I don't have a flight until tomorrow. A hectic travel day for those travelers. Faith joins us now from the Atlanta airport. Faith, fourth of July, just a few days away, and the holiday travel expected to set records.

That's right, Rachel. The TSA expected this holiday travel period to peak next Sunday, July seventh, anticipating that it will screen more than three million passengers in one single day nationwide, which would be the agency's busiest day ever. Rachel.

Faith, Thank you. All of that travel could be upended by the heat and storms in the days ahead. Let's go straight to WABC meteorologist Danny Beckstrom. Danny, time this thread out for us.

Rachel, that line of strong to severe thunderstorms is sweeping across the northeast tonight, bringing drenching downpours, damaging wind gusts, and prolific lightning to millions. A severe thunderstorm watch is still in effect for many from North Carolina up through Maine until this front pushes offshore later tonight. While the northeast is stormy, the south is steamy. The Southern half of the country settling into a stretch of scorching heat through the fourth of July. We're talking triple-digit heat indices for places like Houston, Tulsa, New Orleans. Now to the tropics, Barrel is the big story. The earliest Category 4 hurricane on record in the Atlantic, and the first ever in June after rapidly intensifying today. Unprecedent to see a storm this strong this early in the season. Barrel barreling toward the Windward Islands tonight before continuing through the Caribbean. This is just the second-name storm of the season, but with water temps closer to September's averages, no surprise, we're off to a hot start with several more areas to watch in the Atlantic Basin. Rachel?

Storms in the northeast, to heat in the south. Danny tracking it all for us. Thank you.