Forecasters at the U.S. National Hurricane Center are keeping an eye on two low-pressure systems in the Atlantic Ocean that could develop into tropical storms in the next days.

The large areas of low pressure linked to a tropical wave over the Atlantic at an estimated 825 miles east of the Windward Islands could turn into a tropical depression in the next couple of days, because it move toward west-northwest at up to 20 miles per hour.

A good number of weather models showed the Central Atlantic system would to reach Hispaniola, the second-largest and most populous island of the Antilles, in approximately five days, after reaching the Leeward Islands, the northern group of the Lesser Antilles in the West Indies, and Puerto Rico.

The monitored disturbance closest to the United States is situated about 300 miles east of the Lesser Antilles. Upper-level winds may be a factor in further storm development, said the statement of the division of National Weather Service’s Tropical Prediction Center.

The Leeward Islands, which are located where the Caribbean Sea meets the Atlantic Ocean, include the U.S. Virgin Islands, the British Virgin Islands, Guadeloupe, Anguilla, Saint Martin, Barbuda, Redonda, Saint Kitts, Saba, Antigua and Montserrat.

If one of the systems strengthens into a tropical storm, with winds of 39 to 73 miles per hour, the National Hurricane Center will call it Fay.