Long Island forecast: snow, then rain, sleet Tuesday

Long Islanders leaving home for work Tuesday morning would be well-served to get an early start. 

Snow that started falling Monday night is forecast to give way to a rainy, sleety mess by the time the sun rises Tuesday morning.

The National Weather said between three and five inches of snow will have fallen before it begins mixing with rain about 2 a.m.

Gusts of about 20 mph are also possible, according to the weather. The precipitation is forecast to change to all rain on the South Shore by 7 a.m. Tuesday and by 10 a.m. on the North Shore, as temperatures rise to 40.

Marykate Guilfoyle, a spokeswoman for Suffolk County Executive Steve Bellone, said the county's emergency operations center will be open by 4 a.m. Tuesday to respond to potential needs. "As the county braces for the first significant snowfall of the season, our plow operators will be deployed this evening and remain on staff overnight to salt and clear the roadways," she said.

Long Island Rail Road crews will also be working overnight, keeping third rails clear of snow and ice and helping to keep switches operable, the MTA said in a statement. As of midnight Monday, the railroad had reported no delays.

“Crews will be prepositioned as we monitor conditions for the duration of the storm, with the ability to respond quickly to any issues,” said Metro-North President and LIRR interim president Catherine Rinaldi.

Kennedy and La Guardia airports also reported no delays but warned in tweets that travelers Tuesday morning should check with their airlines for potential weather-related schedule changes.

Much of the South Shore can expect a more mild event — likely no more than two to three inches — while areas north of the Long Island Expressway could get up to five inches, said Bill Goodman, a Weather Service meteorologist. 

"It's looking like a tale of two shores," Goodman said. 

Widespread minor coastal flooding is expected early Tuesday for vulnerable South Shore back bay locations in Nassau, along with areas west of Long Island Sound, making for a messy early morning commute, according to a Weather Service advisory.

Much of what Long Island gets — rain, sleet, snow or some combination — could depend on which side of the freeze line different areas of the Island are on and where the warmer air hits first.

The weather service, which issued a winter weather advisory for the region through 1 p.m. Tuesday, predicts the temperature will be right around 32-33 degrees overnight but said wind chill factors could make it feel like it’s between 20 and 25 degrees.

Nassau County Executive Bruce Blakeman said crews were spreading sand on roads and plows would be out in full force overnight. 

"This could be a significant event so we're taking it seriously," Blakeman said at a news conference Monday in Mineola. " … I would ask everybody to be cautious. It will be slippery to walk. It will be slippery to drive. So just be careful."

While major power outages are not expected, utility companies statewide have about 6,300 workers available for weather-related issues. The NICE bus system also warned of potential weather-related delays, advising riders to check the website for changes.

With John Valenti

By Robert Brodsky

robert.brodsky@newsday.com@BrodskyRobert

Robert Brodsky is a breaking news reporter who has worked at Newsday since 2011. He is a Queens College and American University alum.