pictures across the east coast, up and down the seaboard. Lightning striking one world trade center. That was incredible. You saw it outside of your window. The empire state building. And look at this... See More
pictures across the east coast, up and down the seaboard. Lightning striking one world trade center. That was incredible. You saw it outside of your window. The empire state building. And look at this beautiful picture of lightning right next to a rainbow. It doesn't look possible. But there it is. Ginger knew it was possible. But she knows all things weather-related. We begin with the hurricane threat along the east coast, as we head into the holiday weekend. Our extreme weather team tracking it all. Ginger, we begin with you. We have our team together in Florida and North Carolina. South Carolina feeling it. Hurricane Arthur. It was updated overnight. Max sustained winds, 75 miles per hour, moving towards south and North Carolina today and tonight. That's going to be the worst of this hurricane. So, where does it go after that? Let's check it out. We've got tropical storm warnings from Myrtle Beach up through parts of Virginia. But the hurricane warnings in red. Hatteras island, which has mandatory evacuations. That path taking it over the outer banks. But it's a miss for most of the east coast. That's what I wanted to focus on. So many people asking me, how does it affect me and how much? Quickly, you see it right there, overnight tonight, into early morning. Boston tomorrow night, still raining. New York, D.C., drying out. I'll have much more coming up. Good news on that part. The hurricane moving past Florida this morning. We saw it on the map. Causing dangerous conditions there. Matt Gutman is in Jacksonville beach, Florida, with the latest, hey, Matt. Reporter: Hey, David. That's right. Arthur has been scooting up the coastline here. As it scraped by Florida, it left behind a hidden danger for the millions of beachgoers expected here this weekend. And for the surfers you might see behind me, rip currents invisible to the naked eye, like the one forming right behind me. This morning, with waters churning offshore, red flags flying along on 500 miles of roiling post line, from Florida to North Carolina. Cars stocking up on gas and lined up at the ferry, ready to leave, after a mandatory evacuation was issued for north Carolina's hatteras island. And fourth of July fireworks canceled along the outer banks. Boston, expected to be drenched by Arthur on Friday, moved its Independence day festivities to today indeed. In North Carolina, crews are busy trying to storm-proof windows. Bulldozers are already lining highway 12, ready to handle the possible damage. Officials begging locals to play it safe. It's easy to replace a boat if it gets damaged during the storm. But we can't replace people. Reporter: With Arthur barreling ahead, folks diving into the surf and into Florida on Wednesday. Volusia county ocean rescue. They found someone who just got caught in a riptide. That person was fine. But a high rip current risk for four states. Florida, Georgia, South Carolina and North Carolina. Six people were plucked off out of those waters just yesterday. And today, it is literally all hands on deck. They're even bringing administrative staff here to help out as lifeguards. Amy? You can see the dangerous surf behind. Thank you, Matt. North Carolina, the governor there declaring a state of emergency in two dozen counties. Mandatory evacuations ordered in parts of the outer banks. David Kerley is right along the coast in nags head. David, good morning. Reporter: Morning, Amy. This is where the real strength of Arthur will hit. That's why cape hatteras, about 30 miles down the beach here has been ordered mandatory evacuation. But the governor did declare emergency for all of the counties along the coast. And we did see folks leaving last night. But it's not been a massive evacuation yet. Here's the thing. The governor said don't put on your stupid hat. Be smart about the storm. It's a hurricane.
This transcript has been automatically generated and may not be 100% accurate.