Gulf Coast braces for tropical storm

Satellite image of Tropical Depression 9 taken Thursday at 10:02 p.m. EDT.

MIAMI, Florida (CNN) -- A tropical depression churning over the central Gulf of Mexico may warrant a tropical storm warning by Friday.

National Weather Service forecasters issued a tropical storm watch -- meaning a tropical storm is possible within 24 hours -- from the Suwanee River in Florida westward to just east of Pascagoula, Mississippi.

Maximum sustained winds remain near 35 mph with higher gusts. Tropical Depression 9 would become Tropical Storm Hanna once its current 35 mph winds reach 39 mph.

Some strengthening is possible and the depression could become a tropical storm on Friday, when a general northward motion is expected to resume.

At 9 p.m. EDT, the center of the storm was 270 miles south of Pensacola, Florida. Heavy rain is soaking the Florida peninsula.

The first six storms of the Atlantic season all reached tropical storm strength but fell short of hurricane force 74 mph winds. But the seventh storm, Gustav, barreled offshore from the Atlantic seaboard and reached hurricane status near the Canadian east coast, far from its tropical origins.

By Thursday morning, the fast moving storm had doubled its forward speed to 47 mph, carrying 75 mph sustained winds and higher gusts.

The storm knocked out power and flooded low-lying coastal areas overnight on Nova Scotia, the Halifax Herald reported.

Gustav spread heavy rain and high winds over Nova Scotia, Prince Edward Island and Newfoundland before heading off to the Labrador Sea, where it lost its hurricane status but remained a very large and strong extratropical storm.

Earlier this week, as a tropical storm, Gustav tormented North Carolina's Outer Banks.