MIAMI - Tropical Storm Fay swept into Florida from the Gulf of Mexico and soaked the state on Tuesday while growing strong enough that forecasters said it could become a hurricane before smacking Florida a third time.

Damage was light as Fay blustered diagonally across the peninsula. At 6 p.m. EDT the storm's center was over central Florida about 50 miles south-southwest of Melbourne, the U.S. National Hurricane Center said.

Tropical storms are powered by warm ocean waters and generally weaken quickly once they move ashore. Fay defied expectations by growing stronger over land.

"In fact, it is stronger than it has ever been so far," the hurricane forecasters noted in their advisory.

Fay's top sustained winds rose to 65 miles per hour (105 km per hour), making it slightly stronger than it was when it passed over the Florida Keys on Monday or when it came back ashore in southwest Florida on Tuesday.

The land in Fay's path was so warm and swampy that "it might not register that it's really land at this point," said Corey Walton, a hurricane support meteorologist at the Miami-based hurricane center.

The core of the storm was expected to move into the Atlantic Ocean on Wednesday, possibly growing into a hurricane over the warm Gulf Stream current before curving back into north Florida on Thursday. It would become a hurricane if its sustained winds reach 74 mph (119 kph).

Heavy Rains

The sixth storm of what experts predict will be an unusually busy Atlantic hurricane season, Fay brought gusty conditions and steady downpours to south and central Florida. The rain was needed in a region where development over the past decade has outstripped water supplies.

"Most of the damage has really been limited to the heavy rainfall," Florida Emergency Management director Craig Fugate said. "Street flooding, downed power lines, downed trees, that kind of event."

The storm killed more than 50 people in the Caribbean, most of them in Haiti when a crowded bus was carried away as it tried to cross a rain-swollen river.

In Florida, one of the few serious injuries occurred when a powerful wind gust picked up a man riding a kite board -- a surf board attached to a large kite -- like a rag doll and slammed him into the beach and then a nearby building in Fort Lauderdale.

The weather system toppled trees, signs and awnings in the low-lying Florida Keys island chain and uprooted trees and eroded beaches in the Miami area.

More than 111,400 utility customers in 32 Florida counties lost power due to the storm. Fay delayed the start of the school term in south Florida but classes were scheduled to resume on Wednesday.

Fay kept far away from U.S. oil and gas rigs in the Gulf of Mexico.

Orange juice prices shot up on Monday on fears Fay could hit major citrus growing areas. But traders said the groves would have to be struck by several much stronger storms, as they were in 2004 and 2005, for fruit trees to be affected.

Florida was hit in 2004 and 2005 by a series of hurricanes, including Katrina before it went on to devastate New Orleans and kill 1,500 people on the U.S. Gulf Coast.

(Additional reporting by Scott Disavino in New York and Tom Brown and Jim Loney in Miami, editing by Patricia Zengerle)