Sept 30 (Reuters) - Hurricane Joaquin was gaining strength on Thursday as it moved toward the Bahamas, with forecasts still inconclusive on whether the storm would slam into the U.S. East Coast or head out to sea without making landfall, the Hurricane Center (NHC) said.
Joaquin, the third hurricane of the 2015 Atlantic season, intensified late Wednesday into a Category 3, on a scale of 1 to 5, with maximum sustained winds of 115 miles per hour.
The storm was expected to gain strength and could become a Category 4 over the next day as it moves near or over portions of the Bahamas, the NHC said.
Several models show the hurricane turning north, bringing it to the coast of the Carolinas or mid-Atlantic states on Friday or Saturday, the agency said.
However, the storm's exact path remains unclear, with what the NHC called an "excellent" prediction tool indicating it could cut a path out to sea.
"The range of possible outcomes is still large, and includes the possibility of a major hurricane landfall in the Carolinas," it said.
The governors of New York and Connecticut and emergency-management officials in New Jersey - states all hard hit by 2012's Superstorm Sandy and already facing heavy rains unrelated to Joaquin on Wednesday - warned residents to begin preparations for a possible severe storm.
Virginia Governor Terry McAuliffe declared a state of emergency to deal with flooding this week and the possibility of Joaquin's landfall.
Hurricane warnings were in effect for islands of the central Bahamas and a tropical storm warning was issued for southeastern islands.
Residents on islands closest to Joaquin's path, which include Rum Cay, Long Island, Exuma and Eleuthera, had stocked up on food and drink and were boarding up homes and businesses.
The last hurricane to make landfall in the continental United States was Arthur, which hit North Carolina as a Category 2 storm in July 2014, bringing high winds, driving rain and storm surges up the East Coast.
In October 2012, Sandy struck the New York metropolitan area, killing more than 120 people and causing some $70 billion in property damage, primarily in New York and New Jersey.