Miami ? Hurricane Bill howled over the open Atlantic as a fierce Category 4 storm Wednesday, and it could be energized by warmer waters as it moves north.

Forecasters said Bill should begin pushing large swells toward Bermuda and parts of the southeastern U.S. coast by the weekend, but it wasn’t yet clear how close the storm will come to land. Richard Pasch, a senior hurricane specialist at National Hurricane Center, said computer models continue to keep the storm’s path away from the eastern coast of the United States.

“We can’t be absolutely sure, but we’re feeling pretty good about it,” Pasch said.

The hurricane center did say people in the Leeward Islands should keep an eye on the storm, though its core was expected to pass well to the northeast of the chain in the next day. Fishermen in Antigua were advised to dock their boats.