MIAMI -- The center of Tropical Storm Tammy came ashore in north Florida on Wednesday after skirting the coast and sending heavy rain and gusty winds toward Georgia and the Carolinas.

The center of the storm came ashore near Mayport, the location of a major naval air station about 15 miles east of Jacksonville, but much of the worst weather remained offshore, the National Hurricane Center said.

"Tammy is a minimal tropical storm," said Steve Letro, meteorologist in charge of the National Weather Service in Jacksonville. "The forecast movement will keep the worst of the weather offshore."

At 8 a.m. EDT, Tammy had 40 mph winds and was moving to the west-northwest near 14 mph.

Images: Swimmers Advised To Be Cautious | Slideshow Forecast
Images: Residents Prepare For Wet Weather

Meanwhile, South Florida is under a flash flood watch because of heavy rain expected with the storm.

The National Weather Service says while Tammy is already well north of South Florida, a deep and very moist and unstable air mass will continue across the area for the next several days.

The NWS says 5 to 8 inches of rainfall is possible across South Florida from Wednesday evening through Saturday.

Tammy is the 19th named storm of the Atlantic hurricane season, which began June 1 and ends Nov. 30.

This is tied for the second-busiest season since record-keeping started in 1851; 19 storms also formed in 1995 and 1887. The record for tropical storms and hurricanes in one year is 21, set in 1933.