Updated 11:12 p.m. Heavy snow began falling before midnight Sunday, with total snow accumulations of 12 to 20 inches expected in Huntington, and wind gusts up to 50 mph.
The snow was expected to continue falling throughout the day and evening Monday, until early Tuesday morning. Blizzard-like conditions could be possible Monday morning.
The National Weather Service said travel would be difficult to impossible during the slow-moving storm, with conditions affecting the morning and evening commutes Monday and into Tuesday as the storm lingers.
The Long Island Rail Road is operating on a weekend schedule on Monday and Tuesday and said that it might temporarily suspend service if snow accumulations reach 10-to-13 inches.
Nassau is expected to receive more snow but the track of the storm is uncertain.