Long Island forecast: Heavy, wet snow a concern in 4th nor’easter

A winter storm watch has been issued for Long Island from 4 a.m. Wednesday to 6 a.m. Thursday, with wet, heavy snow possible, as the fourth nor’easter in three weeks is expected, forecasters said.

Accumulation of 4 to 9 inches, locally higher, could be seen on Long Island, starting early morning Wednesday and lasting through late night, the National Weather Service said. Lesser amounts could be seen on the South Fork, from around Westhampton eastward, said Faye Morrone, weather service meteorologist in Upton.

“Plan on difficult travel conditions,” the weather service said, with potential for both morning and evening commutes to be impacted, as “significant reductions in visibility are possible.”

Winds gusting from 25 to 40 mph, combined with heavy snow, could lead to downed tree limbs and resulting power outages, Morrone said.

Also, minor to moderate coastal flooding for Nassau and western Suffolk’s north and south shores is possible around high tide times from Tuesday night to Wednesday night, the weather service said

The system is complex, with uncertainty remaining as to track, timing, precipitation types and amounts, so watch for the forecast to be refined, Morrone said.

There is a chance to see precipitation start as rain in the late afternoon hours of Tuesday, the first day of spring, Morrone said. More significant precipitation, a wintry mix of rain, snow, and sleet, could be starting as early as 2 a.m. Wednesday in some areas, Morrone said, with a switch to all snow by evening, Morrone said. In fact, snowfall rates of 1 to 2 inches an hour are possible later Wednesday afternoon into the evening.

Among the dynamics leading to this parade of March nor’easters is an area of high pressure that’s set up over Greenland, a pattern known to alter the path of the jet stream, “causing it to track across the Northeast, bringing storms with it,” said Jessica Spaccio, climatologist with the Northeast Regional Climate Center, based at Cornell University. While nor’easters are common this time of year, “our weather pattern this month has been stuck, allowing storms to keep tracking this way.”