Tropical Storm Isaias is moving towards Florida with maximum sustained winds of 100 kilometers per hour,
Isaias weakened from a hurricane to a tropical storm Saturday after it blew through the Bahamas.
"Don't be fooled by the downgrade," Florida Governor Ron DeSantis said Saturday.
DeSantis has declared a state of emergency for a dozen counties on the Atlantic coast.
"The most important thing we want people to do now is remain vigilant," DeSantis said.
Isaias is set to sweep along Florida's east coast as the southeastern U.S. state battles an out-of-control COVID-19 outbreak.
Officials in Miami-Dade County said they do not believe it will be necessary to open evacuation centers for this storm but said 20 centers remain on standby in case conditions change.
Florida is one of the hardest-hit U.S. states, with more than 480,000 cases of COVID-19 and more than 7,000 deaths as of Saturday.
The storm has prompted authorities in parts of Florida to close COVID-19 testing sites.
The U.S. National Hurricane Center says the tropical storm warning extends northward along the southeast United States coast to South Santee River in South Carolina.
In North Carolina, in addition to declaring emergencies in coastal counties, Governor Roy Cooper also ordered the evacuation of Oracoke Island, which was hit by last year's Hurricane Dorian.
In the Bahamas, Isaias downed trees and knocked out power. Officials evacuated people in Abaco and in the eastern end of Grand Bahama.