Tropical Storm Sean moved northeast in the Atlantic Ocean Thursday, prompting a tropical storm warning for Bermuda, the National Hurricane Center in Miami said.The storm was about 360 miles west-southwest of Bermuda traveling at 7 mph, the center said in its 10 a.m. EST advisory.Forecasters said Sean could strengthen during the next 24 hours and possibly reach hurricane strength. However, the storm was expected to begin weakening by late Friday.Tropical storm conditions were expected to reach Bermuda by Thursday evening. Sean also was expected to produce 1-3 inches of rain on the island.Swells generated by Sean began affecting parts of the southeastern U.S. coast and Bermuda, causing life-threatening surf and rip currents, the hurricane center said.