Storm system Hermine spun away from the U.S. East Coast on Sunday, removing the threat of heavy rain but maintaining enough power to churn dangerous waves and currents -- and keep beaches off-limits to disappointed swimmers and surfers during the holiday weekend.

The National Weather Service said a tropical storm warning remains in effect for New Jersey and Delaware, including Rehoboth Beach, which could experience wind gusts of up to 80 km/h and life-threatening storm surges during high tide late Sunday and into Monday.

Virginia Beach also remained under a tropical storm warning, with the weather service saying that large and breaking waves and dangerous rip currents pose a threat to anyone who enters the surf. No significant rainfall was expected for the area, although scattered rain may occur in parts of southern New England and in the mid-Atlantic states.

In New Jersey, tropical storm-force winds could whip up on Labor Day. Gov. Chris Christie warned that minor to moderate flooding was still likely in coastal areas and said the storm will cause major problems, even as it tracks eastward into the Atlantic.

"Don't be lulled by the nice weather," Christie said, referring to the bright sunny skies along the Jersey Shore on Sunday afternoon. "Don't think that nothing is going to happen, because something is going to happen. ... The eastern track means a less severe impact, but you're still going to see beach erosion, storm surges and dangerous rip currents. There will be impact from this storm."

The National Hurricane Center maintained its tropical storm watch for Martha's Vineyard and Nantucket and said dangerous storm surges would continue along the coast from Virginia to New Jersey.

"The combination of a storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline," the Hurricane Center said in a morning advisory.

Hermine caused two deaths, damaged properties, closed beaches as far north as New York, and left hundreds of thousands without electricity from Florida to Virginia. Dominion Virginia Power said crews were working to restore power to about 5,000 customers in North Carolina and 1,500 customers in southeast Virginia. The company expects service to those customers to be restored by 5 p.m. Monday.

The Florida Division of Emergency Management said on Twitter on Sunday that nearly 80,000 utility customers were still without electricity. Emergency managers say the Anclote River northwest of Tampa is forecast to go well into major flood stage on Sunday afternoon and have issued mandatory evacuations for some low-lying mobile home parks and apartment buildings.

Hermine rose up over the Gulf of Mexico and hit Florida on Friday as a Category 1 hurricane before weakening to a tropical storm across Georgia.

At 11 a.m. Sunday, Hermine's top sustained winds strengthened to 110 km/h as it moved east-northeast at 17 km/h. The storm, expected to turn northward later Sunday, was centred about 500 kilometres east-southeast of Ocean City, Maryland.

Forecasters say Hermine could regain hurricane force later Sunday as it travels up the coast before weakening again to a tropical storm by Tuesday.

Governors all along the coast announced emergency preparations.

And since sea levels have risen up to a foot due to global warming, the storm surges pushed by Hermine could be even more damaging, climate scientists say.

Michael Mann at Pennsylvania State University noted that this century's one-foot sea-level rise in New York City meant 25 more square miles flooded during Superstorm Sandy, causing billions more in damage.

"We are already experiencing more and more flooding due to climate change in every storm," said Michael Oppenheimer, a geosciences professor at Princeton University. "And it's only the beginning."

The winds and rain were so strong Saturday in North Carolina that all bridges to the Outer Banks were closed for several hours 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.

Earlier in Florida, a homeless man died from a falling tree.

Todd Solomon, who lives in an area of Virginia Beach that often floods, said Hermine failed to make the list of the top five storms he's seen. People in his neighbourhood lost power on Saturday and saw water reach the foundations of some homes. But he said he wasn't aware of any buildings that were actually flooded in his neighbourhood.

"If you weren't in the flood prone area, it was like a normal day," he said. "And if your power was out, you kind of bounced around to find a restaurant or grocery store that still had power."

On Sunday afternoon, he said a few homes still lacked power. But most people were cleaning up trees and branches felled by the storm.
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   Gresko reported from Washington. Associated Press contributors include Seth Borenstein in Washington, Jeffrey Collins in Columbia, S.C., Tamara Lush in Tampa, Fla., Bruce Shipkowski in Seaside Heights, N.J., and Jeff Martin in Atlanta.

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Gresko reported from Washington. Associated Press contributors include Seth Borenstein in Washington, Jeffrey Collins in Columbia, S.C., Tamara Lush in Tampa, Fla., Bruce Shipkowski in Seaside Heights, N.J., and Jeff Martin in Atlanta.