Children play in the surf of Hurricane Arthur, at the west end of Ocean Isle Beach, North Carolina. REUTERS/Randall Hill

Miami - Tropical Storm Bertha barreled toward Barbados on Friday, prompting eastern islands in the region to brace for high winds and heavy rain.

The second named storm of the Atlantic hurricane season strengthened slightly, with top winds reaching 50 miles (80 kilometers) per hour, but it was not expected to strengthen further for the next two days, the US National Hurricane Center (NHC) said.

At 1500 GMT, it was located about 70 miles northeast of Barbados, where emergency services canceled a tropical storm warning.

Bertha was expected to pass north of Barbados later Friday before moving through the central Lesser Antilles overnight towards the Virgin Islands and Puerto Rico on Saturday.

Tropical storm warnings were in effect for St. Lucia, Dominica, Martinique, Puerto Rico, Vieques, Culebra, the US Virgin Islands and the British Virgin Islands, meaning tropical storm conditions were expected there within the next 24 hours.

A tropical storm watch was issued for the eastern Dominican Republic, though the Miami-based NHC urged Haiti, which shares the island of Hispaniola with the Dominican Republic, and other countries in the northeastern Caribbean to monitor the storm's progress.

Up to six inches (15 centimeters) of rain were forecast for the affected areas.

“Tropical storm conditions are expected to first reach the warning area this afternoon, making outside preparations difficult or dangerous,” NHC forecasters said. The Atlantic hurricane season began June 1 and runs through November 30.

The season is expected to be quieter than usual, the NHC has said, with between eight and 13 tropical storms, of which three to six could rise to hurricane strength.