Hurricane Isaias was bearing down on a number of units of the National Park System./NOAA

Isaias, which was downgraded to a tropical storm Saturday but expected to regain hurricane strength, was bearing down on south Florida, and units of the National Park System from Everglades National Park north to Cape Hatteras National Seashore on the Outer Banks of North Carolina were boarding up and closing down.

Everglades and Biscayne national parks both closed Friday evening, Canaveral National Seashore in Florida and Cape Lookout National Seashore on the Outer Banks of North Carolina planned to shutter Saturday, and Cape Hatteras was to close Sunday.

Other parks that planned to close in advance of the storm included Fort Sumter and Fort Moultrie National Historical Park, and Charles Pinckney National Historic Site, which planned to close Sunday as well. Timucuan Ecological and Historic Preserve, including Fort Caroline National Memorial, Kingsley Plantation, Cedar Point, Theodore Roosevelt Area, and Spanish Pond, all in south Florida, closed Saturday evening.

Officials in Dare and Hyde counties in North Carolina had issued evacuation orders for visitors to the Outer Banks, including those at Hatteras and Ocracoke islands within Cape Hatteras National Seashore. Due to the forecast for life-threatening rip currents along Hatteras Island beaches, Dare County’s state of emergency order includes restrictions on ocean swimming. 

The National Hurricane Center reported that Isaias had weakened while passing over the Bahamas, but it was expected to return to hurricane strength before reaching Florida.

"On the forecast track, the center of Isaias will approach the southeast coast of Florida tonight and move near or along the east coast of Florida Sunday and Sunday night," forecasters at the National Hurricane Center said Saturday evening. "On Monday and Tuesday, the center of Isaias will move quickly from offshore of the coast of Georgia into the southern mid-Atlantic states."

RAINFALL: Isaias is expected to produce the following rain accumulations: Bahamas: 4 to 8 inches, with isolated maximum totals of 12 inches. Cuba: 1 to 2 inches, with isolated maximum totals of 4 inches. Eastern Florida: 2 to 4 inches, with isolated maximum totals of 6 inches. Northeast Florida and coastal Georgia: 1 to 3 inches. Carolinas and the mid Atlantic, including the southern and central Appalachians: 2 to 5 inches, with isolated maximum totals of 7 inches. Southeast New York and much of New England: 2 to 4 inches, with isolated maximum totals of 6 inches.