Tropical Storm Isaac emerged over warm Caribbean waters on Saturday slightly weaker but ready to regroup after dumping torrential rains on Haiti, where thousands of people remain homeless more than two years after a devastating earthquake.

RadioShack-Nissan, a fusion of Lance Armstrong's former team and Leopard-Trek, are focused on the Tour of Spain and had no comment on overnight developments that threaten the American's Tour de France wins.

Tropical Storm Isaac headed towards the Dominican Republic and Haiti on Friday, rumbling slowly west across the Caribbean after unleashing heavy rain on parts of Puerto Rico.

Tropical Storm Isaac unleashed heavy rain and winds off Puerto Rico and the Virgin Islands as it moved across the Caribbean on Thursday and could strengthen into a hurricane before tearing across the Dominican Republic and Haiti.

Tropical Storm Isaac weakened slightly as it dumped heavy rain off Puerto Rico and the Virgin Islands on Thursday but it was expected to strengthen into a hurricane before tearing across the Dominican Republic and Haiti, U.S. forecasters said.

American long-distance swimmer Diana Nyad pushed ahead on Monday, overcoming a night of lightning, rain and whipping winds in her latest bid to become the first person to swim from Cuba to Florida without a shark cage.

Tropical Storm Helene made landfall off the Gulf of Mexico on Saturday and weakened into a tropical depression as it plowed up Mexico's east coast, the U.S. National Hurricane Center said.