AMNA NAWAZ: Welcome to the "News Hour."

Millions of Americans along the Gulf Coast are on high alert due to life-threatening conditions as Hurricane Isaias gains power and moves closer to land.

Isaias rapidly intensified overnight from a tropical storm to what is now a Category 2 hurricane, making it the first one in the Atlantic this year.

Residents are securing their homes and gathering supplies.

Local and state officials are issuing evacuation orders.

And forecasters are warning of heavy rain, damaging winds, flooding, storm surges, and the possibility of tornadoes.

Florida Governor Ron DeSantis said his state will be ready.

GOV.

RON DESANTIS (R-FL): And I will just say we have got everyone mobilized, the full monty for the storm.

We're taking it very seriously.

I hope it weakens.

I think there's conditions where it could.

But our assumption is that it's going to hit strong as a probably lower-end category 3.

AMNA NAWAZ: Joining us now is Michael Brennan.

He's director of the National Hurricane Center.

So, Michael, knowing the path could still change here, let's just start with the latest you know on the potential path of this hurricane and when it could make landfall.

MICHAEL BRENNAN, Director, National Hurricane Center: Well, the storm has strengthened over the last several hours, now a Category 2 hurricane on the Saffir-Simpson scale.

It's going to continue to move off to the northeast over the next several hours overnight and then turn more towards the north.

Right now, we're thinking that the center is going to make landfall somewhere in the Alabama or Florida Panhandle coastline, but where the exact center crosses land is not as important as the impacts.

You're going to see impacts all along the Northern Gulf Coast from this system.

AMNA NAWAZ: You mentioned how rapidly it intensified.

It's already a Category 2.

Is there any way to tell just how powerful this storm could be when it makes landfall?

Could it possibly reach Category 3 or more?

MICHAEL BRENNAN: Over water, yes.

There's a small window of opportunity for it to continue to intensify tonight, potentially taking it close to Category 3 strength overnight.

But we think weakening will commence later tonight or tomorrow as it approaches the coastline.

So we're really looking at maybe a Category 1 or 2 as it makes its approach, final approach, to landfall.

But, regardless, a lot of people get really hung up on the intensity and the categories.

I think the hazards are largely baked at this point, meaning that, no matter what intensity the storm comes ashore as, the hazards are largely going to be unchanged, We're going to see a lot of storm surge, rainfall, flooding, and potential for strong, impactful winds moving inland over some of these Southern Tier states with long-duration power outages.

AMNA NAWAZ: We know those residents are being urged to prepare.

What kind of preparations should they be making?

How far inland should they be preparing, and when and how do people make that decision to evacuate?

MICHAEL BRENNAN: So, first and foremost, I'm glad you mentioned the evacuations.

There are a number of mandatory or recommended evacuations along the Northern Gulf Coast here, especially coastal Alabama, portions of Mississippi and even Florida Panhandle.

If you've been ordered to evacuate, you need to go ahead and do that right away.

Don't assume that you'll have the entirety of tomorrow to make necessary preparations or evacuate.

You can see in the satellite imagery here the conditions are already spreading well out in front of this storm, so we're not going to have all day tomorrow to prepare or evacuate if ordered to do so.

AMNA NAWAZ: That is Michael Brennan, director of the National Hurricane Center, joining us tonight.

Michael, thank you for your time.

MICHAEL BRENNAN: Thank you.