Ian, now a Category 3 hurricane with 120 mph winds, has strengthened on Tuesday and is forecast to strengthen even more into the night.

The latest track shows Ian making landfall on Wednesday, striking the west coast of Florida between Tampa and Fort Myers, bringing flooding and damaging winds.

Hurricane warnings are in effect from Tampa to Fort Myers and storm surge warnings are in effect for a large portion of Florida’s west coast.

There is also a risk for tornadoes in Florida Tuesday and Wednesday.

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."

The Orlando International Airport said operations will stop at 10:30 a.m. Wednesday.

The St. Pete-Clearwater International Airport is closing at 1 p.m. Tuesday while Tampa International Airport is suspending flights at 5 p.m. Tuesday.

The Sarasota Bradenton International Airport is closing at 8 p.m. Tuesday while the Melbourne Orlando International Airport will stop flights at 2 p.m. Wednesday.

Hurricane Ian’s track is moving south, with landfall forecast for late afternoon Wednesday between Tampa and Fort Myers as a Category 3 storm.

The storm surge forecast for Tampa Bay has dropped from 10 feet to 8 feet. But now the predicted storm surge for Fort Myers has increased and could be as high as 12 feet.

Tropical Storm Ian has weakened slightly, but it is expected to not only strengthen but rapidly intensify overnight as it travels over warm waters in the Caribbean.

As of 5 p.m. ET, the storm system had maximum sustained winds of 45 mph and was moving west-northwest at 12 mph, with the center located about 220 miles away from Grand Cayman.

Dry air ahead of the storm has delayed the strengthening trend so far. But the rapid intensification is expected to occur Monday into Tuesday as the system continues across the northwestern Caribbean and closes in on western Cuba.

Over the next 24 hours, the outer bands will impact Jamaica and the Cayman Islands, bringing rounds of heavy rain, possible flash flooding and storm surge. Later Monday and into Monday night, Ian will be closing in on western Cuba and will likely bring significant wind and storm surge impacts to the region.

A hurricane warning is in effect for Grand Cayman and portions of western Cuba. A tropical storm watch has been issued for portions of western Cuba, as well as the lower Florida Keys, including Key West.

As of 5 p.m., the forecast track was nudged slightly eastward. Overall, the forecast guidance variability and uncertainty will remain high, and the track for where the storm will be from the middle to the end of the week will continue to shift over the next 24 to 48 hours.

-ABC News' Dan Peck