Tropical Storm Helene is expected to unleash mudslides and flooding in Cuba before reaching major hurricane strength on Thursday as it hits Florida with life-threatening ocean surge, the U.S. National Weather Service said.

HAVANA (Reuters) - Tropical Storm Helene is expected to unleash mudslides and flooding in Cuba before reaching major hurricane strength on Thursday as it hits Florida with life-threatening ocean surge, the U.S. National Weather Service said.

A tropical storm or hurricane could develop this week in the Gulf of Mexico. The National Hurricane Center gives it a 70 percent chance that a system will organize enough to become a tropical depression or named storm over the next few days.

Cubans reinforce bridges and prepare theirbelongings ahead of Tropical Storm Helene:: Guanimar, Cuba::Helene was churning about 180 miles (277 km) south of the western tip of Cuba as it barreled northwest,