Long Island forecast: 'Dangerous' blizzard to slam NYC region with 20 inches of snow, whiteout conditions, damaging winds

A dangerous blizzard is bearing down on Long Island and the New York City area that will bring whiteout conditions, damaging winds and snowfall accumulations of 15 to 20 inches, according to the National Weather Service.

The blizzard warning is in effect beginning Sunday at 1 p.m. and continues into Monday afternoon across the tristate area, the weather service said, with snowfall and road conditions that could greatly limit travel and disrupt normal life well into Tuesday.

Gov. Kathy Hochul declared a state of emergency on Long Island starting Sunday morning ahead of the nor'easter.

"It's time to brace for impact, New Yorkers," Hochul said at a news briefing Saturday afternoon, adding that New York is "in the crosshairs of a very dangerous, fast moving, potentially life-threatening winter storm."

The blizzard conditions will bring heavy snow, high winds, and whiteout conditions that are expected to cause "dangerous to impossible travel" the tristate area from Sunday night through Monday afternoon, the weather service said.

Forecasters expect strong to damaging wind gusts Sunday night into Monday afternoon.

Widespread moderate coastal flooding is expected for the high tide cycle from Sunday night into early Monday morning for much of the coast. Some major coastal impacts are possible for the southern bays of western Long Island, the Twin Forks and the North Shore of Long Island, the NWS said.

Dune erosion is likely, with localized overwashes possible along the ocean beachfront Sunday night into Monday morning, and high seas are expected on the waters that surround Long Island.

Most flights arriving at the New York City airports Sunday were canceled.

At Kennedy Airport, 62% of arrivals and 41% of departing flights were canceled as of about 7 a.m., according to the website FlightAware.

At LaGuardia, 62% of arrivals and 46% of departures were canceled.

The Long Island Rail Road reported its trains were on or close to schedule at 6 a.m., but warned that disruptions are possible given the intensity of the storm.

An advisory on the site notes that the snow is likely to affect service on the trains. LIRR officials told Newsday the railroad would monitor conditions to ensure safety and that snow-clearing equipment and deicing trains were ready for deployment.

Ten inches of snow accumulating on the tracks can jeopardize electrical connectivity between trains and the third track, the LIRR has said. During past storms, the railroad has preemptively suspended service so as not to risk stranding trains with passengers on board.

The Long Island Rail Road reported its trains were on or close to schedule at 7 a.m., but warned that disruptions are possible given the intensity of the storm.

Many public libraries on Long Island were closed Sunday. Some religious education programs were closed or operating remotely.

Hochul said Saturday she activated 100 members of the National Guard to assist with snow response throughout Long Island, New York City and the lower Hudson Valley region.

"It looks like we have a pretty solid 19 or 20 inches Islandwide," Bill Goodman, a meteorologist at the National Weather Service in Upton, said in an interview Saturday afternoon. "There’s still potential for some places to see 2 feet of snow."

At 7 a.m., Republic Airport in East Farmingdale was reporting 36 degrees and east winds of 12 mph under overcast skies. Long Island MacArthur Airport in Islip reported 35 degrees and east winds of 10 mph, also overcast.

At JFK, it was 37 degrees with east winds of 14 mph.

Light snow will begin Sunday morning but will ramp up in the evening and overnight into Monday. Snowfall rates of 2 to 3 inches an hour are expected late Sunday night, Goodman said. That will cause dangerous to impossible travel, as visibility will be at or below a quarter mile at times, particularly for the coast, the weather service said. The storm could also bring rare occurrences of thundersnow during the heaviest snowfall, Goodman said.

Dangerous winds and heavy, wet snow will increase the potential for power outages.

In an update Saturday evening, PSEG Long Island officials said they are staffing additional utility crews to respond to any outages. Those crews include more than 600 line workers, tree trimmers and other field workers and another 260 mutual aid personnel, the utility said.

PSEG officials cautioned that high winds may delay power restoration but said crews will work in 16-hour shifts until all outages are repaired. Some outages may "extend beyond 24 hours," the company wrote in an email Saturday.

NewsdayTV meteorologist Geoff Bansen said Saturday evening, "It’s very dangerous stuff. ... We're going to get clobbered."

"A blizzard warning at the end of the day is about visibility. ... If the snow is blowing enough, it doesn't have to be a monster storm. There could be 3 inches of snow, but if it's blowing it could make the visibility near zero."

At a Suffolk weather briefing Saturday, County Executive Edward P. Romaine said the mild weather should not give anyone false hope. Unlike last month’s major snowfall, which was accompanied by a spate of extreme cold, Sunday and Monday's highs will be in the mid-30s and will be followed by rising temperatures next week, forecasters said.

High winds and blizzard conditions in the forecast are "very concerning," Romaine said as he stood before a towering pile of sand and salt in a storage barn in Yaphank.

"Please stay off the roads. Do not plan to travel," Romaine said.

The county Department of Public Works commissioner, Charles Bartha, said Suffolk was "well prepared" for the storm, with 8,000 tons of salt on hand and additional deliveries expected on Saturday. The department plans to staff about 120 employees starting midday Sunday, Bartha said.

Suffolk County Police Commissioner Kevin Catalina echoed the need for residents to stay home. "We don't want the roads clogged up because we have to get out there and answer those emergency calls," Catalina said.

Winds could gust up to 55 mph in Suffolk and 45 mph in Nassau, according to the weather service. The East End could see the most intense gusts around 65 to 70 mph, the weather service's Goodman said Saturday. "The heaviest snow and the strongest winds are going to coincide with each other," he said.

Meanwhile, the Nassau County Society for the Prevention of Cruelty to Animals reminded Long Islanders that pets should not be left outside during storms.

"All animals must be inside," the SPCA said Saturday. "If an animal is left outside and suffers frostbite, hypothermia or worse, it is a crime and you will be arrested."

Newsday's Tracy Tullis contributed to this report.

Check back for updates on this developing story.