michael brennan: rapid intensification is exactly what it says. a storm intensifies, strengthens very quickly, a 30- to 35-mile-per-hour increase into sustained winds within about 24 hours. and that can result in some of the most dangerous storms that we've seen. allison chinchar: hurricane patricia, back in 2015, was the most intense tropical cyclone on record in the western hemisphere. it went from a tropical storm to a category 5 hurricane in just 24 hours. watch out. holy crap. [thunder crashes] we see that lightning activity tends to become frequent right before a storm is going to intensify. [thunder crashes] imagine a fireworks show and you see all of the fireworks popping, popping. and that has been something of an indicator that that storm may rapidly intensify. [thunder crashes] derek van dam: no, we're not necessarily getting an increase in the number of hurricanes, but the proportion of the most severe hurricanes is becoming more frequent. michael brennan: warmer atmosphere holds more moisture, and storms are going to get worse as the

people who live in coastal or low lying areas we earlier heard from national hurricane director michael brennano said the threat is that this system may practically become a stationary one, bringing a torrential rains to three different states. >> the biggest threat and most widespread threat is going to be the heavy rainfall and the potential for considerable flooding flash and urban flooding across portions of florida and into the coastal southeastern united states from today all the way through thursday. and there will be the possibility of river flooding in many locations as well as that heavier rainfall falls on drains into river basins. >> florida governor ron desantis earlier said that he's activated both the florida national and state guard to be ready for rescue and humanitarian assistance. >> the florida national guard alone is standing by with 3,000 service members who will be ready to assist the state emergency response team. it could get up to 85, 859095 mile an hour. sustained. when that is absolutely possible particularly in parts of the state like here in tallahassee he there's

just a few minutes we're going to talk live to the director of the national hurricane center, michael brennan. we'll talk with him and just a little bit in meantime, we are less than 48 hours away from vice president kamala harris introducing her running mate at a campaign event in philadelphia. she's in the final hours of her decision-making process to select a running mate who she helps can how hopes can help her defeat trump and win the white house today, she's meeting with at least three top contenders, pennsylvania governor josh shapiro, minnesota governor tim walz, and arizona senator mark kelly. let's go now to cnn's eva mckend, who's been keeping an eye on all the movement, the comings and goings outside the vice president's residence biden's there at the naval observatory in washington, dc. eva, what have you seen and heard today well, jessica, i can tell you that we spotted former attorney general eric holder. >> he of course for us is so significant in this process because he's overseeing this team of democratic attorneys involved in this rapid vetting process of these top contende

including leon panetta, john brennan, michael hayden and james clapper sign a letter saying the laptop earmarks of a russian information operation. generated headlines first in politico and substantial tv conch, expose you all as fools and useful idiots for the russians. >> serious questions don't whether the russians are using rudy giuliani to interfere in the u.s. presidential election. >> we do know that it's a very active russian campaign. that's according to the u.s. intelligence community. >> joe biden took the same line in a debate with donald trump. >> look, there are 50 former national intelligence folks who said that what this -- he is accusing me of is a russian plant. >> others, such as npr refused to cover the story. then managing editor terrence samuels saying we don't want to waste our time on stories that are not really stories. when the "new york times" and "the washington post" confirmed the laptop's authenticity a year and a half later, scarborough said he had just been raising questions but it doesn't let the media off the hook. zuckerberg now says feign was wrong a