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

Forecasters at the National Hurricane Center said the storm now had maximum sustained winds of 40 mph (65 kph). Debby was located about 100 miles (160 kilometers) west–southwest of Key West, Florida, and it was moving toward the northwest at 14 mph (22 kph).

Wind and thunderstorms have spread over a broad region, including southern Florida, the Florida Keys and the Bahamas.

Debby is likely to bring drenching rain and coastal flooding to much of Florida’s Gulf Coast by Sunday night, and predictions show the system could come ashore as a hurricane Monday and cross over northern Florida into the Atlantic Ocean.

Forecasters warn it could also drop heavy rains over north Florida and the Atlantic coasts of Georgia, South Carolina and North Carolina early next week.

Debby is the fourth named storm of the 2024 Atlantic hurricane season after Tropical Storm Alberto, Hurricane Beryl and Tropical Storm Chris, all of which formed in June.

The National Hurricane Center in Miami predicted that the system will strengthen as it curves off the southwest Florida coast, where the water has been extremely warm. Intensification was expected to proceed more quickly later on Sunday.

A hurricane warning was issued for parts of the Big Bend and the Florida Panhandle, while tropical storm warnings were posted for Florida’s West Coast the southern Florida Keys and the Dry Tortugas. A tropical storm watch extended farther west into the Panhandle. A warning means storm conditions are expected within 36 hours, while a watch means they are possible within 48 hours.

Tropical storms and hurricanes can trigger river flooding and overwhelm drainage systems and canals. Forecasters warned of 6 to 12 inches of rain, and up to 18 inches in isolated areas, which could create “locally considerable” flash and urban flooding. Forecasters also warned of moderate flooding for some rivers along Florida’s West Coast.

Heaviest rain could be in Georgia, South Carolina

Some of the heaviest rains could actually come next week along the Atlantic Coast from Jacksonville, Florida, through coastal regions of Georgia, South Carolina and North Carolina. The storm is expected to slow down after making landfall.