MIAMI — Subtropical Storm Nicole began strengthening and transitioning into a tropical storm early Tuesday as it churned toward the northwestern Bahamas and Florida’s Atlantic coastline, forecasters said.

“There are indications in the satellite imagery and recognizance aircraft that the system may be trying to evolve into a more classic tropical cyclone and could become a full-blown tropical storm later today,” Jack Bevin, a senior hurricane specialist at the Miami-based National Hurricane Center, told The Associated Press on Tuesday morning.

A range of warnings and watches remain in place. Many areas are still reeling from damage caused by Hurricane Ian, which hit Florida’s southwestern Gulf Coast as a Category 4 storm in late September, before dumping heavy amounts of rain across much of central part of the state.

Hurricane warnings were in effect for the Abacos, Berry Islands, Bimini and Grand Bahama Island, the advisory said. Other areas of the Bahamas, including Andros Island, New Province and Eleuthera remained under a tropical storm warning.

The hurricane center said the storm’s track shifted slightly north overnight, but the exact path remains uncertain. It was expected to make landfall along Florida’s coast as a Category 1 hurricane late Wednesday or early Thursday.

In the U.S., tropical storm warnings and hurricane watches were issued for much of Florida’s Atlantic coastline north of Miami, to Altamaha Sound, Georgia. The warning area stretches inland, covering Florida’s Lake Okeechobee, with tropical storm watches in effect on the state’s Gulf Coast — from Bonita Beach in southwest Florida to the Ochlockonee River in the Panhandle.

Bevin said the storm has a “very large cyclonic envelope,” meaning that even if it makes landfall along the central Florida coastline, the effects will be felt into Georgia.

However, the storm was not expected to have any impact on voting in Florida on Tuesday, Bevin said.

Officials in the Bahamas opened more than two dozen shelters across the archipelago on Tuesday as they closed schools and government offices in Abaco, Bimini, the Berry Islands and Grand Bahama.

Authorities warned that airports and seaports will close as the storm nears and not reopen until Thursday as they urged people in shantytowns to seek secure shelter.

Communities in Abaco are expected to receive a direct hit from Nicole as they still struggle to recover from Hurricane Dorian, a Category 5 storm that hit in 2019.

“We don’t have time to beg and plead for persons to move,” said Capt. Stephen Russell, emergency management authority director.

The difference between a subtropical and tropical storm is largely academic. A subtropical storm is a non-frontal low-pressure system that has characteristics of both tropical and extratropical cyclones and tend to have a larger wind field, extending much farther from their centers.

At 7 a.m., the storm was about 385 miles (615 kilometers) east northeast of the northwestern Bahamas and moving at 8 mph (13 kph), with maximum sustained winds of 50 mph (80 kph).

The Atlantic hurricane season runs from June 1 through Nov. 30. The last storm to hit Florida in November was Tropical Storm Eta, which made landfall in Cedar Key, on the state’s Gulf Coast, on Nov. 12, 2020.