Two Americans peer into a flooded street in front of their hotel as Hurricane Sally passed through the area on Wednesday local time in Pensacola, Florida. The storm is bringing heavy rain, high winds and a dangerous storm surge to the area. Photo: AFP

A swath of the US East Coast, including New York City, was under alert Saturday, as storm Henri was upgraded to what could be the first hurricane in 30 years to hit New England.

Forecasters warned of violent winds, heavy rainfall, the risk of flash floods and surging seas as the storm churned in the Atlantic, packing maximum sustained winds near 75 miles (120 kilometers) per hour.

Nasty weather that preceded Henri forced New York City to halt its star-studded Central Park concert that was billed as a "homecoming" for a metropolis hard hit by the pandemic.

The approaching hurricane had prompted New York Governor Andrew Cuomo to announce a state of emergency and the deployment of 500 National Guard soldiers in anticipation of response efforts.

"It's as serious as a heart attack," he warned.

He said the storm was expected to make landfall on Long Island, home to the plush Hamptons villages where wealthy New Yorkers retreat in summer, around noon on Sunday.

"It will be about a 26-hour event," Cuomo added, telling New Yorkers to expect "significant power outages" and "significant flooding" in some suburbs of the Big Apple.

Henri was anticipated to miss New York City by miles, but it could still cause tropical storm conditions beginning Saturday night.

The US National Hurricane Center warned of "a dangerous storm surge, hurricane conditions and flooding" in areas of southern New England and Long Island, confirming in its 11 pm advisory that the storm continued to steam north.

The National Weather Service said late Saturday Henri was expected to remain a Category 1 hurricane at landfall.

Henri is expected to produce three to six inches of rain (7.5 to 15 centimeters) across the region.

AFP