In a worst-case scenario for the U.S., a major hurricane could hit Florida's Gulf coast, but forecasters say it would have to clear several hurdles.

Tropical Storm Sara has formed in the Caribbean and is expected to bring life-threatening rainfall, flooding, and the potential for mudslides to parts of Central America, the National Hurricane Center said.

New storm models show the storm—which has a 90 percent chance of forming in the next seven days—could strike Florida's coast.