Coastal storm — with snow likely — heads for Long Island, NWS says

Forecasters said a coastal storm will likely bring snow Sunday into Monday but the "puzzle pieces" in the unstable low pressure system is making it difficult to predict how much.

There is about a 30% chance of heavy snow, but forecasters say the chance of 6 inches or more is trending downward as the storm moves south of Long Island and is still developing, according to the National Weather Service.

Meteorologists said they are still watching elements of the storm that could still bring snow, but it likely won’t look like the massive storm of last month, which left a foot of snow on Long Island, or last as long. The storm could still bring high winds and coastal impacts, according to the weather service.

"There’s a low probability right now and we don’t know which way it will go," said  NWS meteorologist David Stark. "Right now, this is all evolving. There are too many unknowns. The potential is there but we don’t know how much. A lot of puzzle pieces are needed to get the storm to develop. If they’re not together at the same time, it may be offshore and we may not have precipitation at all."

It may also be wetter snow than the powder that fell in January and was later coated in sleet and ice, Stark said.

The difference between this storm and the January system is the lack of arctic air accompanying it. The January storm brought weeks of extreme cold in its wake.

After a brief respite of temperatures into the 40s through Saturday, with rain expected Friday and possibly Saturday morning, the mercury is expected to dip back into the low 30s and 20s by Sunday and last into early next week. The cold will be enough for snow to fall on Long Island but will not be in the teens to single digits seen last month, Stark said.

The end of February also brings longer days, and conditions 5 to 10 degrees below normal Monday and Tuesday, Stark said. He said temperatures could again climb into the 40s by later next week.

"It will likely warm up after that," Stark said. "Any new snow won’t stick around nearly as long as we previously saw."

By John Asbury

john.asbury@newsday.comJohnAsbury

John Asbury is a breaking news and general assignment reporter. He has been with Newsday since 2014 and previously worked at The Press-Enterprise in Riverside, California.