Tropical Storm Eta has dumped torrents of blustery rain on Florida's west coast as it marched over the Gulf of Mexico towards an expected landfall north of the heavily populated Tampa Bay area.
The National Hurricane Center in Miami expects Eta to slog ashore on Thursday and then move northeast across Florida as it loses strength.
Eta briefly gained hurricane strength on Wednesday morning but forecasters said it later weakened to tropical storm status with maximum winds of 110km/h.
There were no immediate reports of any injuries, serious damage or flooding in the Tampa Bay area as the storm skirted past that region Wednesday afternoon.
Several tornado warnings were issued but there were no reports of one touching down.
The storm had meandered in the Gulf of Mexico since crossing over southern Florida on Sunday.
Early on Thursday, Eta was about 100km north northwest of St Petersburg, Florida, and moving northward at 10km/h, the hurricane centre said. Eta had maximum winds of 60km/h.
Slow weakening is expected as Eta approaches the west coast of Florida during the next few hours, followed by more rapid weakening after landfall occurs later Thursday.
Eta is forecast to dissipate over the western Atlantic Ocean by the weekend.
The hurricane center said "life-threatening storm surge" was possible early on Thursday and forecasters advised residents to heed warnings from local officials.
The storm first hit Nicaragua as a category four hurricane and killed at least 120 people in Central America and Mexico, with scores more missing.
Eta hit land late on Sunday as it blew over Lower Matecumbe Key, in the middle of the chain of small islands that form the Florida Keys, but the heavily populated areas of Miami-Dade and Broward counties bore the brunt of the fury with heavy rainfall.
It was the 28th named storm of a busy Atlantic hurricane season, tying the 2005 record for named storms. And late Monday, it was followed by the 29th storm, Theta, far out in the Atlantic Ocean hundreds of kilometres from the Azores.