(CNN) -- Tropical Storm Tomas formed in the Atlantic Friday and could strengthen into a hurricane by late Saturday, the National Hurricane Center said.
The storm, which was reported as the 19th named storm of the 2010 Atlantic hurricane season, formed southeast of the Windward Islands. It had maximum sustained winds of some 60 miles per hour, the center said Friday evening.
Tropical storm warnings were in effect for Barbados, Saint Vincent and the Grenadines, Martinique, Saint Lucia, Trinidad and Tobago and Grenada. The government of Barbados issued a tropical storm watch for Dominica, hurricane center said.
Tracking maps indicate Tomas is moving west-northwest at around 15 mph and is forecast to pass through the central Windward Islands Saturday afternoon. Friday evening, Tomas was located about 170 miles southeast of Barbados.
It could become a hurricane by late Saturday as strengthening is forecast for the next 48 hours, the hurricane center said.
The storm is expected to bring rainfall of between three and five inches -- with up to eight inches possible -- across parts of the Windward and southern Leeward Islands. Storm surge is also predicted, the hurricane center reported.
Meanwhile, Tropical Storm Shary, the 18th named storm of the season, was located about 80 miles south-southeast of Bermuda. It had sustained winds of 70 mph and was forecast to pass east of the island late Friday.
Shary is expected to weaken starting Saturday and transition into an extratropical low, the center said.