Idalia updates: Damaging tornadoes, severe flooding from Florida to Carolinas

Airlines and The Federal Aviation Administration said it's monitoring Tropical Storm Idalia as it heads to the U.S.

The FAA posted on social media that it's "closely monitoring" Idalia's path, but it isn't responsible for closing airports and canceling flights.

American Airlines issued a travel alert that allows its customers whose plans are impacted by Idalia to rebook their flights without incurring a change fee.

Southwest Airlines said it anticipates some changes to its schedule and an impact on its operation as the storm approaches. The airline has issued a travel advisory for its customers.

United Airlines has issued travel waivers for customers traveling to and from impacted airports. The company said it's working to ensure its team is prepared to deal with the expected severe weather.

Multiple counties in Florida are under mandatory and voluntary evacuations as Tropical Storm Idalia barrels toward the state.

People living in zones in Pinellas, Pasco, Citrus, Hillsborough, Levy, Manatee, Sarasota and Taylor counties must evacuate the area, according to multiple county officials.

County officials are also urging people living in mobile homes, low-lying areas and along the coast to leave the area as Idalia approaches.

Officials in Hernando, Jefferson, Manatee and Pasco counties have also issued voluntary evacuation orders for particular zones.

-ABC News' Michael Pappano, Jianna Cousin and Robinson Perez

The Federal Emergency Management Agency is encouraging everyone in Idalia’s path to "get prepared today."

FEMA Administrator Deanne Criswell spoke to Florida Gov. Ron DeSantis and "emphasized the agency's actions and readiness to support the state’s needs." FEMA is also "closely coordinating" with Georgia and South Carolina to provide support as needed.

President Joe Biden also spoke with DeSantis earlier Monday and approved an emergency declaration.

-ABC News' Justin Gomez

Tampa International Airport will close at 12:01 a.m. Tuesday as Idalia nears.

A hurricane warning has been issued from the Tampa Bay area up to the Apalachicola area.