Forecasters say they expect Tropical Storm Helene in the Caribbean Sea to strengthen rapidly and become a hurricane as it moves north across the Gulf of Mexico on Wednesday toward the U.S.

Tropical Storm Helene formed over the northwestern Caribbean on Tuesday and triggered a tropical storm warning for the Lower Florida Keys. The storm is forecast to be a major hurricane for the Florida panhandle Thursday.

Tropical Storm Helene has formed in the northwestern Caribbean Sea and is expected to rock the Florida Gulf Coast later this week as a Category 3 hurricane.  Current sustained winds are 50 miles per hour as it tracks northwest at 12 miles per hour.