Heavy snow will intensify Sunday evening into Monday, with rates of 2 to 3 inches per hour creating near-zero visibility along the coast, according to National Weather Service meteorologist Bill Goodman in Upton. The storm threatens power outages from heavy, wet snow and gusts peaking at 65 to 70 mph on the East End, Goodman said. Travel will turn dangerous to impossible through Monday afternoon across the tristate area.

Hochul urged New Yorkers to prepare during a Saturday briefing. “It’s time to brace for impact,” she said. “New York is in the crosshairs of a very dangerous, fast-moving, potentially life-threatening winter storm.” She activated 100 National Guard members for snow removal in Long Island, New York City and the lower Hudson Valley.

Airports grounded most flights. At Kennedy Airport, 61% of Sunday arrivals and 41% of departures stood canceled as of 5 a.m., FlightAware data showed. LaGuardia saw 62% of arrivals and 46% of departures scrapped.

Long Island Rail Road trains ran on schedule early Sunday but snow threatened delays. Officials positioned snow-clearing gear and de-icing units. PSEG Long Island added 600 line workers, tree trimmers and 260 mutual aid staff for outages. High winds and deep snow could stretch some blackouts past 24 hours, the utility warned in a Saturday email.

Coastal flooding hits Sunday night high tides, with moderate surges along much of the shoreline and major impacts possible in western Long Island’s southern bays, the Twin Forks and North Shore. Up to 2.5 feet of inundation threatens low-lying spots under a coastal flood warning through 5 a.m. Monday. Dune erosion and beach overwash loom along oceanfronts, while high seas batter surrounding waters.

Suffolk County Executive Edward P. Romaine called conditions “very concerning” at a Yaphank briefing Saturday. Highs near mid-30s Sunday and Monday offer no relief from winds and blizzard force. “Please stay off the roads. Do not plan to travel,” he said. Public Works Commissioner Charles Bartha reported 8,000 tons of salt ready, plus more incoming, and 120 staffers deploying midday Sunday.

Suffolk Police Commissioner Kevin Catalina pressed residents to stay home. “We don’t want the roads clogged up because we have to get out there and answer those emergency calls,” he said. Winds may hit 55 mph in Suffolk, 45 mph in Nassau.

Goodman pegged islandwide totals at 19 to 20 inches, with 2 feet possible in spots. Light snow starts Sunday morning, exploding overnight. Thundersnow could punctuate peak bands. NewsdayTV meteorologist Geoff Bansen called it “very dangerous stuff.” A blizzard warning hinges on blowing snow slashing visibility, he added—even lighter totals can paralyze if winds whip flakes into whiteouts.

Nassau County SPCA issued a pet alert. “All animals must be inside,” officials said Saturday. Leaving pets out risks frostbite, hypothermia or death—a crime carrying arrest.