Tropical Storm Eta spun toward Florida's west coast on Wednesday on its erratic path to a fourth landfall, threatening squall winds, storm surge and prompting the state's governor to declare a state of emergency in 13 counties.

Eta, which had weakened slightly from hurricane strength to become a tropical storm, is the 28th named storm of the busiest Atlantic hurricane season on record, according to the Miami-based National Hurricane Center. Its fourth landfall was projected early on Thursday, north of Tampa Bay, after it already slammed Central America, Cuba and the upper Florida Keys.

It had dropped nearly 18 inches of rain over parts of South Florida by Monday, moved southwest and then stalled over the Gulf of Mexico on Tuesday before making a northward turn. It was last moving on a northward trajectory at 12 miles per hour (19 kph).

The storm was about 85 miles (135 km) southwest of Tampa, with maximum sustained winds of 70 miles per hour (110 kph)on Wednesday, the NHC said.

The west coast of Florida faces "the multiple threats of a landfalling hurricane or tropical storm," said Dennis Feltgen, a meteorologist for the National Weather Service, listing the heavy rainfall, storm surge and possible tornadoes in the forecast.

"One is of course the wind, which could be at the very least gusting to hurricane force, and sustained tropical storm force winds. That's enough to do some damage," Feltgen said.

"Even though it looks relatively calm out here, the weather can change in an instant," Tampa Mayor Jane Castor said at a press briefing. "Remain vigilant."

She added there were no reports of flooding or street closures as of Wednesday afternoon and she believed the city could withstand the projected storm surge "safely."

Eta's surge was expected to affect southern and western Florida and the Florida Keys into Thursday. The state's west coast was under a storm surge warning from the Suwanee River to Bonita Beach, including Tampa Bay, where the water could rise up to five feet.

Florida Governor Ron DeSantis declared a state of emergency in 13 counties in Eta's path and requested that the Federal Emergency Management Agency (FEMA) also declare a pre-landfall state of emergency for those counties to mobilize resources.

Parts of Broward County, on Florida's east coast, were still severely flooded, with lakes overflowing and residential streets submerged. Rainfall totals from Eta could add up to 20 inches in some parts of South Florida, the NHC said.