Elsa weakened to a tropical storm early on Wednesday and is expected to hit the north Florida Gulf coast later in the morning or early afternoon, the US National Hurricane Center said.
It had strengthened to a hurricane, the first of the season, on Tuesday night along south west of Tampa Bay.
The storm was 70 miles (95 km) west of Tampa, Florida, with maximum sustained winds of 65 miles per hour (100 km per hour), the NHC said in an advisory issued at 5 a.m. ET.
Elsa also briefly strengthened to a hurricane last week, when it killed at least three people, blew roofs off homes, toppled trees and sparked flooding in Caribbean island nations east of Cuba.
"Elsa will move near or over portions of the west coast of Florida this morning, then make landfall along the north Florida Gulf coast by late this morning or this afternoon," the NHC said.
Hurricane warnings that had been issued along a stretch of Florida's west coast were downgraded to tropical storm warnings.