A tropical storm warning was issued Sunday for Alabama to the Florida Panhandle as Debby lashed parts of the Gulf Coast with wind and rain.
The National Hurricane Center in Miami said Sunday morning that Debby was about 170 miles southeast of the mouth of the Mississippi River. It said the storm warning has now been issued from the Mississippi-Alabama border eastward to the Florida Panhandle's Ochlockonee River.
Debby's top sustained winds had increased to about 60 mph. It is expected to become a Category 1 hurricane at some point.
People from Texas to Florida should remain alert to Debby's movement.
Forecasters said Debby could be near hurricane strength by Monday night. Meanwhile, up to six inches of rain were possible along the coast, with isolated amounts possibly reaching 10 inches.