(CNN) -- Tropical Storm Debby, the fourth named storm of the Atlantic hurricane season, formed Saturday in the central Gulf of Mexico, the National Hurricane Center reported.
The storm, packing winds of 50 mph with higher gusts, was located about 220 miles south-southeast of the mouth of the Mississippi River, according to the center's 5 p.m. advisory.
Tropical storm warnings were posted from the mouth of the Pearl River, west to Morgan City, Louisiana, but do not include New Orleans. Such warnings indicate tropical storm conditions are expected within 36 hours in the warning areas.
The storm was moving north at 6 mph and is expected to turn west Sunday. Some strengthening is expected over the next two days, the center said.
The hurricane center predicted a possible storm surge of up to 3 feet along the coast, with estimated rainfall amounts between 3 and 6 inches.
Debby's formation marks the first time in history that four named storms have formed before July 1, according to CNN Meteorologist Monica O'Connor.