Irma has strengthened over the eastern Atlantic to become the fourth hurricane of the 2017 Atlantic hurricane season, the U.S. National Hurricane Center said in its latest advisory on Thursday.

Irma is forecast to become a major hurricane by Thursday night and is expected to be an extremely dangerous hurricane for the next several days, it said.

Irma is located about 1,845 miles (2,975 km) east of the Leeward Islands with maximum sustained winds of 100 mph (155 km/h), the Miami-based weather forecaster said.