ST. PETERSBURG, Fla. — Isaias snapped trees and knocked out power as it blew through the Bahamas on Saturday and churned toward the Florida coast, threatening to complicate efforts to contain the coronavirus in places were cases are surging.

Isaias weakened from a hurricane to a tropical storm Saturday afternoon, but was expected to regain hurricane strength overnight as it barrels toward Florida.

"We'll start seeing impacts tonight," Florida Gov. Ron DeSantis warned at a news conference. "Don't be fooled by the downgrade."

Isaias is piling another burden on communities already hard-hit by previous storms and the pandemic.

Florida authorities closed beaches, parks and virus testing sites, lashing signs to palm trees so they wouldn't blow away. The governor warned residents to expect power outages and asked to have a week's supply of water and food on hand. Officials wrestled with how to prepare shelters for people to seek refuge, if need be, while safely social distancing because of the virus.

Authorities in North Carolina ordered the evacuation of Ocracoke Island, which was slammed last year by Hurricane Dorian. Meanwhile, officials in the Bahamas opened shelters for people in Abaco island to help those who have been living in temporary structures since Dorian devastated the area, killing at least 70 people.

Isaias' maximum sustained winds dipped steadily Saturday and were near 70 mph around 8 p.m., hours after the U.S. National Hurricane Center downgraded its status. It said Isaias would regain hurricane strengthen by early Sunday.

By Saturday evening, the storm was about 100 miles southeast of Fort Lauderdale, Florida. It was moving northwest at 9 mph and expected to be near Florida's southeast coast early Sunday, then tack near or along the state's Atlantic coast during the day.

Isaias is expected to remain a hurricane through Monday, then slowly weaken on its climb up the Atlantic seaboard. It's expected to move offshore of the coast of Georgia en route toward the mid-Atlantic states. Heavy rain, flooding and high winds could batter much of the East Coast during the week.

Despite the approaching storm, NASA says the return of two astronauts aboard a SpaceX capsule is still on track for Sunday afternoon. Doug Hurley and Bob Behnken are preparing to make the first splashdown return in 45 years, after two months docked at the International Space Station. They are aiming for the Gulf of Mexico just off the Florida Panhandle, and flight controllers are keeping close watch on the storm.