Washington - Forecasters said Monday that the first hurricane of the season had developed in the Atlantic Ocean and was continuing to strengthen.

Hurricane Bill became a category one storm early Monday and could strengthen into a major hurricane by Wednesday, the National Hurricane Centre in Miami said. The storm had winds of 150 kilometres per hour and was slowly moving westward.

Bill was located about 1,735 kilometres east of the Lesser Antilles at 1500 GMT, and was following behind Tropical Depression Ana, which was dumping heavy rains on Puerto Rico.

Ana, with 55 kilometre winds, was forecast to bring 5 to 10 centimetres of rain to Puerto Rico, the US and British Virgin Islands and the Dominican Republic. The storm was expected to weaken Monday.

A third storm, Claudette, had also weakened to a tropical depression and was bringing 7 to 25 centimetres of rain and winds of about 55 kilometres per hour to the southern US state of Alabama. Heavy rain also fell across western Florida, and the storm was expected to move into the state of Mississippi later Monday.(dpa)