Hurricane Idalia remains a Category 2 storm with sustained winds up to 105 mph.

Idalia is moving at 16 mph to the north and is now 155 miles away from Tampa, Florida.

Hurricane and storm surge warnings in Florida are in effect for Englewood, Longboat Key and Tampa Bay, according to the National Hurricane Center.

-ABC News' Kenton Gewecke

More than 2,200 flights Tuesday are delayed and over 500 flights are canceled across the U.S. as Idalia nears.

So far, more than 500 U.S. flights are canceled for Wednesday.

Currently the Tampa International Airport and St. Pete–Clearwater International Airport are closed. Sarasota-Bradenton International Airport is set to close at 7 p.m. Tuesday.

-ABC News' Amanda Maile

Florida Gov. Ron DeSantis urged people ordered to evacuate to leave now if they haven't already.

"If you are in an evacuation zone and you've been directed to evacuate, particularly if you're in a low-lying area or coastal area, in that Big Bend region, now's the time to do it," DeSantis said during a press briefing. "If you wait much longer, by the time we get in further into tonight, the weather is going to start getting nastier and nastier."

Kevin Guthrie, director of the Florida Division of Emergency Management, said he is "greatly concerned about Cedar Key," where he expects a storm surge of 12 to 13 feet.

DeSantis said that 28 counties in Florida now have some kind of evacuation order -- including Alachua County, home to Gainesville. Over 50 shelters have been set up throughout the state, he said.

Idalia is expected to intensify to a Category 3 hurricane overnight, according to the National Hurricane Center, which warned in its latest advisory that "life-threatening" storm surge could reach 10 to 15 feet in some of the Big Bend area.

The impact of the eyewall is expected to arrive sometime Wednesday morning, DeSantis said.

The latest track shows Hurricane Idalia making landfall southeast of Tallahassee in the northern Big Bend area. This is a bit farther west than the previous track.

Idalia is then expected to skirt across southern Georgia and the Carolinas with tropical storm force gusts and flooding rain Wednesday through Thursday.

Isolated tornadoes will also be possible.

Extreme winds are possible far inland off the Florida coast because of how quickly the storm is moving -- even Gainesville to Valdosta could see 110 mph winds.

-ABC News' Melissa Griffin

A tornado watch has been issued until 6 a.m. ET for 3.7 million people in the western peninsula of Florida.

This means tornadoes are possible to form in the outer bands of Hurricane Idalia through the night.

-ABC News' Kenton Gewecke