Ian, now a major Category 3 hurricane, is growing stronger in the Gulf of Mexico

Hurricane Ian became a major Category 3 storm early Tuesday and will continue to strengthen as it approaches Florida, according to the National Hurricane Center.

Ian made landfall early Tuesday in western Cuba, U.S. officials said. Landfall was just southwest of the town of La Coloma in the Pinar del Río province around 4:30 a.m. ET, with maximum sustained winds of 125 mph.

The hurricane, now in the southeastern Gulf of Mexico, is moving north toward Florida at 10 mph and growing stronger, according to the National Hurricane Center's 2 p.m. update.

The center of Ian could potentially strengthen into a Category 4 hurricane later Tuesday as it continues to move over the Gulf, NBC News forecasters said.

Ian will then approach the west coast of Florida, potentially making landfall late Wednesday into Thursday morning as a Category 2 or 3 storm, according to the National Hurricane Center.

Models now show the storm landing somewhere between Tampa Bay and Charlotte Harbor. The system is still forecast to slow down as low as 3 to 4 mph, prolonging the impacts from heavy rain, strong wind and storm surge.

Follow along for NBC News’ live coverage of Hurricane Ian

Tornadoes over the Florida peninsula are also possible over the next three days.

Storm surge can also affect Florida's east coast where a warning has been issued from Marineland to St. Marys River, along Georgia's coast, according to the hurricane center.

Florida Gov. Ron DeSantis declared a statewide emergency, saying Ian could bring several feet of storm surge. Ian can bring up to 12 feet of storm surge to Charlotte Harbor and 7 feet to the Tampa Bay area, according to forecasters.

"What we have here is really historic storm surge and flooding potential," he said at a news conference Tuesday morning. "That storm surge can be life-threatening."

DeSantis encouraged residents to heed evacuation orders in place from Pinellas County down to the Fort Myers area by getting to higher ground. About 2.5 million residents are under some type of evacuation orders, he said.

Parts of the state may also be without power anywhere from three days to a week, according to Florida Division of Emergency Management Director Kevin Guthrie, who spoke at the news conference.

Georgia and South Carolina may also see some impact from the storm.

A storm surge watch was issued from St. Marys River to south Santee River in South Carolina, and a tropical storm warning along the East Coast was extended north to Altamaha Sound in Georgia and south to Boca Raton, Florida.

The area along the East Coast, north of the Altamaha Sound to south Santee River, can also receive tropical storm weather, according to the hurricane center.

Hundreds of thousands of people were evacuated from Cuba’s Pinar del Río as authorities sent in emergency and medical personnel ahead of the storm’s arrival this week, The Associated Press reported.

Two hours east, in Havana, fishermen hauled out their boats, city workers unclogged storm drains, and residents expressed alarm at the prospect of flooding, according to the AP.

"I hope we escape this one, because it would be the end of us," Abel Rodrigues, 54, told the news agency. "We already have so little.”

Earlier Monday, Ian passed by the nearby Cayman Islands with no major damage reported. Emergency officials issued an "all clear" notification at 3 p.m. local time, and Premier Wayne Panton said the British territory was "very fortunate to have been spared the worst of a potentially very serious storm."

As the storm headed for Florida, oil companies evacuated workers from deep-water platforms in the Gulf of Mexico, and airports in Tampa, Orlando and Pinellas County in Florida announced that they would close Tuesday and Wednesday. American Airlines announced travel waivers for people flying to or out of 20 airports in Florida and the Caribbean.

The Tampa Bay Buccaneers said the team was temporarily moving its operations to Miami-Dade County.

Residents on Florida's Gulf Coast stocked up on food and prepared with sandbags and plywood for their windows. Hundreds of thousands of people were under evacuation orders.

“This storm is trending to slow down, which means it could potentially sit on top of us for 47 hours,” said Cathie Perkins, the director of Pinellas County Emergency Management, NBC affiliate WFLA of Tampa reported.

“That’s a lot of rain, and it’s not going to be able to drain out quickly,” she said.