The system formed as Gulf low pressure became better defined and thunderstorms and rain increased; forecasters expect gradual strengthening into a tropical storm near the Florida Panhandle and Alabama coast.
Tropical storm watches were posted for parts of the Panhandle and Alabama, and the center warned the storm could bring high winds, heavy rain and flash flooding from western Florida to the Texas coast.
If upgraded, the system would be named Bertha, the Atlantic season's second named storm after Arthur; forecasters said Saharan dust and strong wind shear should keep it from reaching hurricane strength.