Tropical Storm Ernesto was spinning westward in the Caribbean Sea on Sunday, barreling toward Mexico's Yucatan Peninsula, US forecasters said.

At 1500 GMT, the eye of the storm was located about 210 miles (340 kilometers) south of Kingston, with Ernesto expected to dump up to six inches (15 centimeters) on Jamaica as it moves south of the island later in the day, according to the Miami-based National Hurricane Center.

The storm had top winds of 50 miles per hour, and was moving westward at 23 miles per hour.

Squalls were ripping through the southern coast of Hispaniola, the island shared by the Dominican Republic and Haiti. "Showers and thunderstorms, occasionally heavy, are possible over the Dominican Republic and Haiti today," the NHC said.

Ernesto was expected to move north of the northeastern coast of Honduras late Monday before making landfall in the Yucatan.

A tropical storm warning was in effect for Jamaica, while Grand Cayman island and parts of the Honduran coast were under a tropical storm watch, meaning tropical storm conditions are possible in the coastal area within the next 48 hours.

The current forecast model has Ernesto brushing the northern coast of Honduras and parts of Nicaragua, then making landfall in the Mexican state of of Quintana Roo, home to the busy beach resort city of Cancun, on Wednesday.

Further east, Tropical Storm Florence had top winds of 60 miles per hour as it headed westward at 14 miles per hour. The sixth named storm of the Atlantic season was located 770 miles west of the Cape Verde Islands and was not expected to strengthen further.