Hurricane Bill became a Category 4 storm as it rumbled across the Atlantic early Wednesday with maximum sustained winds near 135 mph.
And forecasters say the dangerous hurricane could get even stronger.
The National Hurricane Center said people in the Leeward Islands should monitor Bill's progress, though the core of the storm was expected to pass well to the northeast of the islands late Wednesday and early Thursday.
"The wind sheer is light and the waters are warm," Todd Kimberlain, a forecaster at the center, said Tuesday. "Those are two essential ingredients not just for the formation, but also the maintenance, of hurricanes."
Early Wednesday, Bill was centered about 460 miles east of the Leeward Islands and moving west-northwest near 16 mph.
The most significant threat could be to Bermuda, which the storm could pass in three or four days, Kimberlain said. But it also could move directly between Bermuda and the eastern coast of the U.S. without making landfall.
Either way, people near the coast can expect wave swells and rip currents in the next few days, Kimberlain said.
Meanwhile, people in flood-prone Haiti and the Dominican Republic awoke to good news Tuesday as it appeared Ana, the first named storm of the Atlantic season, had largely spared their shared island.
The two countries that share the island of Hispaniola are vulnerable to storms, with many impoverished people clustered along rivers, but there were no reports of major damage from the remnants of Tropical Storm Ana. The system had been downgraded to a tropical depression and then largely dissipated before reaching Haiti and the Dominican Republic, but its rains were still considered a potential threat.
Forecasters had revised their Atlantic hurricane season predictions for this season after the first two months passed without any named storms developing.
Associated Press writers David Fischer and Jonathan M. Katz in Port-au-Prince, Haiti, contributed to this report.