After 9 a.m. Saturday, the chance of snow is high, at 70 percent, but how much snow or even rain and flooding depends on the track of a northeast-moving storm, said meteorologists at the Upton-based service.
The closer the system gets to the Island, the higher the snowfall will be, but if it turns a bit west, rain and maybe flooding could be part of the weather, said meteorologist Mike Layer.
"If it comes too close to the coast, we could even see rainfall along the coast," he said. "If it comes far enough west, it'll actually bring warm air from the ocean."
Winds are expected to be light Saturday at 5 to 10 mph but should gain strength overnight, reaching up to 30 mph Sunday, when gusts could go as high as 40 mph.
"Right now, we're not looking at a significant storm system," Layer said.
Still, weekend temperatures will be lower than the average for this time of year, with daytime highs in the low to mid-30s during the day, he said, and Sunday night lows falling to about 20, he said.
Advisories and warnings for coastal flooding expired Thursday afternoon as the remnants of a winter nor'easter moved away from the Island, the National Weather Service said.
Rain of up to 1.5 inches and wind gusts of up to 70 mph did mostly minor damage overnight into Thursday.
About 151 customers were without power just after 9 p.m., down from 1,100 customers at 1 p.m. Thursday, according to the Long Island Power Authority.
Passengers hoping to get in and out of Kennedy, LaGuardia and Newark Liberty airports saw delays and flights canceled, according to the Federal Aviation Administration.
With Gary Dymski
and Patricia Kitchen