Eta regained hurricane strength Wednesday morning as Florida braced for a second hit from the storm.
The storm's maximum sustained winds increased to around 75 mph (120 kph) off Florida's southwest coast.
Forecasters at the National Hurricane Center in Miami issued a hurricane watch for a 120-mile stretch that includes Tampa and St. Petersburg. The storm has been in the Gulf of Mexico since crossing over South Florida on Sunday.
The latest hurricane watch extends from Anna Maria Island, which is south of St. Petersburg, to Yankeetown.
Eta was about 130 miles west-southwest of Fort Myers early Wednesday and moving at 15 mph (24 kph).
The hurricane center said “life-threatening storm surge" is possible early Thursday, and forecasters advised residents to heed warnings from local officials.
Tropical storm-force winds are expected in the area by late Wednesday.
Forecasts call for more rain from the storm system over parts of already drenched South Florida.
“Never seen this, never, not this deep,” said Anthony Lyas, who has lived in his now-waterlogged Fort Lauderdale neighbourhood since 1996.
He described hearing water and debris slamming against his shuttered home overnight as the storm crossed Florida.