A State of Emergency is now in effect in the city because of the snow, with New Yorkers urged to stay at home if possible.
Above-ground subway service will be suspended early Tuesday morning and NYC public schools will be closed due to a winter storm that could drop more than a foot of snow on the five boroughs.
Gov. Andrew Cuomo says above-ground subway lines will shut down by 4 a.m. Tuesday.
There are currently no plans to cut below-ground subway service, according to officials.
Express subway service ended at midnight.
This is the third year in a row that the MTA has canceled at least some subway service because of snow.
A determination has yet to be made regarding LIRR and Metro-North service.
A decision on any service changes are expected to be posted to the MTA's website around 4:30 a.m.
The State of Emergency by Mayor Bill de Blasio and Cuomo allows the city to mobilize all resources necessary to combat the storm.
De Blasio announced earlier Monday that New York City public schools will be closed Tuesday due to the storm.
The New York City Public Library system will also be closed Tuesday, and the Citi Bike service closeed for rentals at 11 p.m. Monday.
Amtrak will operate a modified schedule in the northeast, with no Acela Express service between New York City and Boston, and modified Acela Express service between New York City and Washington, D.C.
A blizzard warning is in effect as New Yorkers brace for the storm.
NY1 has lowered its initial forecast of up to 20" of snow, and is now forecasting that the city will be hit with between 8 and 15 inches.
Manhattan and the Bronx are slated to get the most.
The forecast called for the snow to start around 11 p.m. Monday. The worst of the snow is expected to hit between 4 a.m. and 10 a.m. Tuesday.
Rain and sleet are expected to start mixing in with snow around 8 a.m. Tuesday, with most of the snow accumulation finishing by 10 a.m.
The Department of Sanitation has 700 salt spreaders ready to go.
It will deploy thousands of plows across the five boroughs once two inches of snow accumulate.
New Yorkers can track progress of sanitation spreader and plow vehicles through the PlowNYC program at nyc.gov/plownyc
Blizzard conditions are expected to make driving particularly hazardous, with high winds and low visibility causing additional problems.
In order to make work easier for sanitation crews, residents are asked to keep the roads clear.
People NY1 spoke with say they have already stocked up for the late-winter blast.
"My dad was a Boy Scout leader so be prepared is the motto," said one. "Have flashlights, water and food. Done deal."
"We already did a little shopping," said another. "Stored up our little cans, and we got our sheets and we're ready to go. Yes sir, because you know, when it gets real cold in the living room I like to lay up."
There's a hazardous travel advisory in effect for Tuesday.
Alternate side parking is cancelled for Tuesday and Wednesday.
The mayor is also asking people to be patient.
"People need to understand that, because of the intensive accumulation, do not expect to see blacktop for quite a while as we proceed during tomorrow," the mayor said at a Monday press conference. "I think it's going to be normal to see a lot of streets where the snow covers the streets throughout the day as sanitation [department] tries to deal with a vast volume of snow coming in."
"Hopefully as we get into the evening tomorrow, sanitation will gain the advantage," de Blasio said. "But for the daytime hours tomorrow, do not expect to see a lot of blacktop in New York City."