MEXICO CITY (AP) — Forecasters say Tropical Storm Selma has formed off the coast of Central America and is heading toward El Salvador.

The U.S. National Hurricane Center says Selma is located about 180 miles (290 kilometers) south of San Salvador, the nation's capital. It has maximum sustained winds of 40 mph (65 kph) and is heading northwest at 5 mph (7 kph).

The center says Selma is expected to dump heavy rains over El Salvador and parts of Guatemala, Honduras and Nicaragua, threatening possible flash floods and landslides.

A tropical storm warning was in effect Friday for the entire coast of El Salvador, and Guatemala declared a tropical storm watch for its Pacific coast. Selma was forecast to make landfall Saturday.