Tropical Storm Ernesto churned westward Sunday toward waters south of Jamaica, threatening to dump several inches of heavy rain on the island during its passage through the central Caribbean. The U.S. National Hurricane Center in Miami said at 5 a.m. EDT Sunday that Ernesto was centered about 240 miles (385 km) southeast of Kingston, Jamaica. Ernesto had maximum sustained winds of about 50 mph (85 kph) and was moving westward at 22 mph (35 kph), according to a report of the Associated Press. The storm wasn't expected to strengthen much during the day. But it was forecast to gradually begin gaining power Monday in the warm Caribbean waters and possibly reach hurricane strength by Monday evening. Ernesto was following a course predicted to take it south of the Cayman Islands on Monday and over the beach resorts of Mexico's Yucatan Peninsula by Wednesday.