Henri’s anticipated landfall on Long Island or southern New England is expected to pose risks much of the surrounding area.
And even if it doesn’t hit those areas as a hurricane, it will be dangerous enough to bring damaging winds and storm surges that threaten to bring down trees and power lines and cause major flooding.
A hurricane warning was in effect for much of the Long Island coast along with parts of Connecticut and Massachusetts and Block Island.
A combination of storm surge warnings and watches were in place for much of Long Island and the Massachusetts coastline, the NHC said.
A storm surge warning means there is a danger of life-threatening inundation from rising water moving inland from the coastline.
“The combination of a dangerous storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline,” NHC forecasters said.
A hurricane landfall in the region would be rare. Long Island has not had a direct hurricane hit since Gloria in 1985; New England last saw a hurricane landfall with Hurricane Bob in 1991.
Henri’s wind field — which is the radius around the storm — at landfall is expected to be a quarter of the size of Sandy’s, CNN meteorologists said.
“Henri is a much more compact storm than Sandy was when it made landfall,” CNN weather producer Robert Shackelford said.
Tropical weather warnings in the Northeast
More than 50 million people in the Northeast are currently under tropical weather alerts, according to CNN meteorologist Tyler Mauldin. That includes more than 12 million people under a storm surge warning, over 5 million people under a hurricane warning and over 37 million people under a tropical storm warning.
The warnings mean these conditions are expected within 24 hours.
“If you live in a coastal, low-lying or area prone to historic flooding due in Guilford, evacuate now. If you live in Zone 1 or 2 in Branford … evacuate by 9pm,” Scanlon wrote. “PLEASE TAKE THIS SERIOUSLY.”
Groton Mayor Keith Hedrick also told CNN the city decided to order mandatory evacuations in some neighborhoods, and authorities will go door-to-door in those parts of town to advise residents to leave ahead of the hurricane.
The National Guard in New York, Massachusetts, Connecticut and Rhode Island was also activated or otherwise poised ahead of the storm to help with any rescues, cleanup and other support, officials said.
Central park sees record rain
In Manhattan, Central Park set a daily record rainfall of 4.45 inches Saturday, the National Weather Service said. The heavy rain edged out the previous record of 4.19 inches dating back to 1888.
Meanwhile, other areas in New York City saw 4 to 8 inches of rain, with Brooklyn receiving more than 6 inches in a 24-hour period.
Across the Hudson River, neighboring New Jersey saw rain totals of 1 to 3 inches in 24 hours.
A flash flood watch remains in effect through Monday morning, with an additional 3 to 6 inches of rain expected for parts of New Jersey, Pennsylvania, New York and Vermont, with higher amounts possible.
New York Gov. Andrew Cuomo warned people in flood-prone areas.
“If you know you are in an area that tends to flood … get out of that area now, please,” Cuomo said in a televised news briefing Saturday.
Cuomo said he would declare an emergency for areas including Long Island, New York City, Westchester and Hudson Valley. New York has heavy equipment deployed on Long Island and water-rescue teams ready to go, Cuomo said.
CNN’s Tyler Mauldin, Robert Shackelford, Joe Sutton, Chris Boyette, Artemis Moshtaghian, Jason Hanna contributed to this report.