Roger Heim (right) and Terry Smith (second from right), both of Valrico, Fla., fill sandbags in preparation for the weekend storm at the Edward Medard Conservation Park in Plant City, Fla.
Caption

Roger Heim (right) and Terry Smith (second from right), both of Valrico, Fla., fill sandbags in preparation for the weekend storm at the Edward Medard Conservation Park in Plant City, Fla. / AP

A tropical depression strengthened into Tropical Storm Debby north of Cuba on Saturday and was predicted to become a hurricane as it moves through the Gulf of Mexico on a collision course with the Florida coast.

The National Hurricane Center said in an update posted at 11 p.m. Saturday that Debby was located about 50 miles (80 kilometers) west-southwest of Dry Tortugas National Park in Florida and about 260 miles (415 kilometers) south-southwest of Tampa. The storm was moving northwest at 14 mph (22 kph) with maximum sustained winds of 45 mph (75 kph).

All points on the Florida Keys west of Seven Mile Bridge have been put under a Tropical Storm Warning, along with much of the state's west coast — from close to Gainesville as far south as the Everglades.

Such warnings indicate the NHC expects tropical storm conditions could appear in those regions by very late Sunday night.

A Hurricane Watch is also now in effect farther to the north, on a roughly 200-mile stretch of the panhandle from Indian Pass down to Yankeetown, with the worst conditions expected to hit the coastline early Monday.

Storm surges also were expected along large parts of Florida's west coast, and up to 15 inches of rain could fall in some parts of the state and across the southeastern U.S. over the next several days.

The NHC said winds would slowly strengthen in the coming hours, and that larger wave swells in the coming days could also lead to "life-threatening surf and rip current conditions."

The governors of Florida and Georgia declared states emergency in preparation on Saturday.

Tropical Storm Debby is the fourth named storm of this year's Atlantic hurricane season. Tropical Storm Alberto, Hurricane Beryl and Tropical Storm Chris formed in June.

The Associated Press contributed to this report.