A "few" tornadoes are possible over parts of coastal east-central and northeastern Florida on Thursday morning, according to the National Weather Service.

The tornado threat will spread northward across parts of southeastern Georgia and the Carolinas later Thursday through Friday morning.

Meanwhile, "large" swell waves generated by Nicole will affect the northwestern Bahamas, the east coast of Florida and much of the southeastern U.S. coast during the next few days.

"These swells are likely to cause life-threatening surf and rip current conditions," the National Weather Service said in a public advisory on Thursday morning.

A "dangerous" storm surge from Tropical Storm Nicole combined with the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline, according to the National Weather Service.

If the peak occurs at the time of high tide, the National Weather Service said, the water could reach up to 5 feet above ground from Florida's Jupiter Inlet to Georgia's Altamaha Sound, from Florida's St. Johns River to the Fuller Warren Bridge, and from Anclote River to Ochlockonee River in Florida.

"The deepest water will occur along the immediate coast near and to the north of the landfall location, where the surge will be accompanied by large and destructive waves," the National Weather Service warned in a public advisory on Thursday morning.

Through Saturday, Nicole is expected to produce 3 to 5 inches of rainfall from the northwestern Bahamas into portions of the Florida Peninsula, with a maximum of 8 inches of localized rain. The southeastern United States into the central Appalachian Mountains and eastern portions of Tennessee, Kentucky and Ohio could see 2 to 4 inches of rainfall, with a maximum of 6 inches of localized rain along the Blue Ridge Mountains. The northern Mid-Atlantic region into New England could get 1 to 4 inches of rainfall.

"Flash and urban flooding will be possible, along with renewed river rises on the St. Johns River, across the Florida Peninsula today," the National Weather Service added. "Heavy rainfall from this system will spread northward across portions of the Southeast, upper Ohio Valley, Mid-Atlantic, and New England today through Saturday, where limited flooding impacts will be possible."

The center of Tropical Storm Nicole is expected to move across central Florida on Thursday morning, possibly emerging over the far northeastern Gulf of Mexico on Thursday afternoon, then move across the Florida Panhandle and Georgia on Thursday night and Friday, according to the latest forecast from the National Weather Service.

Although "additional weakening" is in the forecast, the National Weather Service warned on Thursday morning that "Nicole remains a large tropical storm" and "strong wind, dangerous storm surge and waves, and heavy rains continue over a large area." Tropical storm-force winds extend outward up to 450 miles from Nicole's center, especially to the north. Sustained winds of 49 mph with a gust of 70 mph were reported early Thursday in Daytona Beach, Florida.

According to the National Weather Service, tropical storm conditions will continue along portions of the eastern coastlines of Florida, Georgia and South Carolina in the warning areas on Thursday. Tropical storm conditions are expected to occur within the warning area along Florida's west coast through Thursday night.

More than 215,000 customers were without power across Florida on Thursday morning due to Tropical Storm Nicole, according to data collected by PowerOutage.us.

As of 7:04 a.m. ET, a total of 215,443 customers did not have power.

-ABC News' Robinson Perez