Nicole strengthened into a Category 1 hurricane on Wednesday evening while making landfall on Grand Bahama, the northernmost island of the Bahamas archipelago, according to the National Weather Service. The storm currently has maximum winds of 75 miles per hour.

Nicole may strengthen into a Category 1 hurricane before making landfall overnight near Fort Pierce. Over the next 24 hours, the biggest threats for Florida will be damaging beach erosion, storm surge up to 5 feet, isolated tornadoes and wind gusts around 70 mph.

Hurricane warnings are in effect from West Palm Beach to Daytona Beach. Tropical storm warnings are in effect for much of Florida and extend up to coastal Georgia and South Carolina.

After landfall, Nicole will quickly weaken as it moves across central Florida and the Panhandle, but it'll bring rain, powerful winds and storm surge.

Three feet to 5 feet of storm surge is expected from West Palm Beach to Jacksonville while Florida’s Big Bend area could see 2 to 4 feet of storm surge.

The heaviest rain -- 8 inches -- will hit central Florida. Flash flooding is also possible.

As Nicole moves north, the heavy rain will stretch into the Mid-Atlantic and New England. Pennsylvania to Vermont could see 2 to 4 inches of rain. Philadelphia, New York City and Boston could see 2 inches of rain and gusty winds.

-ABC News’ Melissa Griffin

Nicole made landfall as a tropical storm on Great Abaco Island in the northwestern Bahamas just before noon local time on Wednesday, according to the National Weather Service.

The storm currently has maximum sustained winds of 70 miles per hour.

Disney World parks will close early Wednesday evening and will remain closed through Thursday morning due to the storm.

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."