Mayor Carlos Gimenez says the county has 20 evacuation centers on standby that could be set up with COVID-19 safety measures.
Isaias had maximum sustained winds of 75 miles per hour (120 kph) Friday morning and it was expected to remain a hurricane for the next few days, according to the U.S. National Hurricane Center in Miami.
As the storm moves now toward the southeast coast of Florida, a hurricane warning is in effect from Boca Raton to the Volusia-Flagler county line, which lies about 150 miles (240 kilometers) north.
The Hurricane Center said heavy rains associated with the storm "may begin to affect South and east-Central Florida beginning late Friday night, and the eastern Carolinas by early next week, potentially resulting in isolated flash and urban flooding, especially in low-lying and poorly drained areas".
Miami's mayor said that social-distancing measures prompted by COVID-19 meant each person in shelters needed to have 40 square feet and no more cafeteria-style dining would be allowed. People who are infected with the new coronavirus and need to evacuate will be isolated in classrooms separate them from the general population, Giménez said. We are out of the cone, but impacts will be felt well away from the center of this system. "It's a challenge, but these are some of the things you have to think about in the age of COVID-19 and now a hurricane".
But he urged people to have seven days with of food, water and medication ready and said that state-run coronavirus testing sites in the areas where the storm could hit will be closed. "We will have thousands of tests that will not be conducted until we get these test sites up and running again".
In Daytona Beach and Polk County, authorities distributed sandbags and other officials advised people to have emergency provisions at home sufficient for three to seven days.
In this image made from video, people look at level of Canovanas river following heavy rain caused by the storm in Alto Trujillo, Puerto Rico, Thursday, July 30, 2020. One man died in the Dominican Republic.
Hurricane warning remains in effect for the northwest Bahamas: the Andros Islands, New Providence, Eleuthera, Abaco, Grand Bahama, Bimini, the Berry Islands and neighbouring Cays.
Two of those islands, Abaco and Grand Bahama, were battered by Dorian, a Category 5 storm that hovered over the area for two days and killed at least 70 people, with more than 280 reported missing. People living in the eastern end of Grand Bahama were also being moved.
Prime Minister Hubert Minnis relaxed a coronavirus lockdown as a result of the impending storm, but imposed a 10 p.m.to 5 a.m. curfew. He said supermarkets, pharmacies, gas stations and hardware stores would be allowed to remain open as long as weather permitted.
"Continue to hunker down", said Trevor Basden, director of the Bahamas meteorology department.
The Bahamas has reported more than 570 confirmed COVID-19 cases and at least 14 deaths. Four have hit the USA, including Hurricane Hanna, which came ashore in south Texas over the weekend and brought flooding rains and storm surge to the coast.Dry air to the north has been holding the system back.
Officials wrestled with how to prepare shelters where people can seek refuge from the storm if necessary, while safely social distancing to prevent the spread of the virus. Lifeguards say they're starting to see a slight of swell in Long Island waters because of the hurricane off the coast of Florida.