The disturbance is forecast to become a hurricane Wednesday and will strengthen as it crosses the eastern Gulf of Mexico.

Visible by satellite, the loop current is the rush of hot Caribbean water that pushes into the Gulf between Cuba and Mexico. It bends toward the southwest coast and then whirls around east, forming a hairpin turn before swooping back out into the Atlantic via the Florida straits.

Much of the Gulf Coast of Florida was placed under hurricane, storm surge and tropical storm watches ahead of an expected landfall Thursday.