Hermine already caused two deaths, damaged properties and left hundreds of thousands without electricity from Florida to Virginia. It also spawned a tornado in North Carolina.
"This is not a beach weekend for anyone in the Mid-Atlantic to the northeast," said Eric Blake, a hurricane specialist at the National Hurricane Center in Miami.
Hermine rose up over the Gulf of Mexico and hit Florida on Friday as a Category 1 hurricane before weakening across Georgia.
By 2 p.m. Saturday, Hermine's top sustained winds had increased again to 70 mph (110 kph) as it moved east at 10 mph (17 kph). The storm was centered 90 miles east of Duck, North Carolina.
Tropical Storm Warnings were in effect as far north as Connecticut, with dangerous storm surge expected along the coast from Virginia to New Jersey. Governors all along the coast announced emergency preparations.
The winds and rain were so strong Saturday in North Carolina that all bridges to the Outer Banks were closed following a deadly accident over the intracoastal waterway.
Tyrrell County Sheriff Darryl Liverman told the Virginian-Pilot that high winds tipped over an 18-wheeler, killing its driver and shutting down the U.S. 64 bridge.
And on Hatteras Island in the Outer Banks, a small tornado spawned by Hermine knocked over two trailers and injured four people, authorities said.
In Florida, a homeless man died from a falling tree.
Forecasters said the system could strengthen back into a hurricane Monday through Wednesday as it moves on an offshore path from the waters of Maryland to Connecticut, before weakening again off New England.
The timing couldn't be worse for communities along the coast hoping for revenue from Labor Day events.
In Rehoboth Beach, Delaware, where the beach was closed to foot traffic and swimming prohibited Saturday, traffic was lighter than normal, said Jim Derrick, whose family businesses include a mini golf course, sea shell store, indoor bounce house and ice cream shop.
"This weekend would normally be a parking lot," he said in a telephone interview. He called the weekend "definitely disappointing," although his bounce house was packed.
Elsewhere along Hermine's path, people were having decidedly less fun.
In Savannah, Georgia, Bacon Fest was canceled Friday and Saturday's Craft Brew Fest was moved indoors.
In Virginia Beach, the storm forced Bruce Springsteen to move a Saturday night concert to Monday. Swimmers were ordered out of the surf in New Jersey.
Joyce Harper and her husband, of Berkely Township, N.J., canceled Monday's family barbecue and took their three young daughters to the Seaside Heights boardwalk to "burn off some energy" ahead of the storm.
"If it's as bad as they expect, then we're all going to be indoors for a couple days. I love my kids, but two days is a long time to be together in close spaces," she said.
Amtrak cancelled or altered some service as the storm approached. And Gov. Andrew Cuomo activated New York's Emergency Operations Center.
With about 300,000 Florida homes still without electricity on Saturday, Gov. Rick Scott said restoring power is his state's top priority.
"I want everybody to have their power. I want them to be able to take a hot shower," he said.
