Florida Gov. Ron DeSantis has activated 5,000 Florida National Guardsmen to armories across the state in preparation for Hurricane Ian, which is forecast to hit the state on Wednesday.

Roughly 2,000 National Guard members from neighboring states such as Tennessee are also being activated to assist, the Florida National Guard said in a statement Tuesday.

"The Florida National Guard is well-equipped, with assets including high-wheeled vehicles, helicopters, boats, generators and more," the statement said.

The U.S. Navy has authorized non-essential personnel in various Florida counties to evacuate.

-ABC News’ Matt Seyler

Hurricane Ian, barreling north toward Florida with 120 mph winds, is now located about 230 miles away from Sarasota.

Ian is expected to make landfall in Florida on Wednesday afternoon or early evening.

Ian's outer bands are already hitting South Florida, bringing a threat of heavy downpours, strong wind gusts, frequent lightning and even tornadoes. A tornado watch is in effect for South Florida until 5 a.m. Wednesday.

-ABC News’ Dan Peck

Walt Disney World and Universal Orlando will close Wednesday and Thursday due to the storm.

As Ian moves north over Florida, tropical storm force winds will reach coastal Georgia and South Carolina.

Tropical storm watches have been issued for Savannah and near Charleston.

Georgia Gov. Brian Kemp has issued a state of emergency.

Federal Emergency Management Agency Administrator Deanne Criswell warned Tuesday, "Floridians are going to experience the impacts from the storm for a very long time."

"Our biggest concern as we wait for this storm to make landfall is storm surge," Criswell said. "In 2018, when Hurricane Michael impacted the Florida Panhandle, there were five recorded fatalities as a result of storm surge. So therefore, if people are told to evacuate by their local officials, please listen to them. The decision you choose to make may mean the difference between life and death."

President Joe Biden on Tuesday urged residents to "evacuate when ordered."

Biden said he spoke to the mayors of Tampa, St. Petersburg and Clearwater Tuesday morning and told them to "contact me directly" for "whatever they need."

Criswell said a search and rescue coordination group has been activated, including members from FEMA's urban search and rescue teams, the Coast Guard, the Department of Defense and the Department of the Interior.

The Red Cross has established 29 shelters and is prepared to open 60 more shelters if needed, she said.

Criswell stressed, "To those who may be watching at home, get ready and do not underestimate the potential that the storm can bring."