New York City will be without transporation tonight in an unprecedented move to maintain public safety during the developing snow storm.

The Metropolitan Transportation Authority and Port Authority will shut down all transit operations and non-emergency vehicles will be banned from city roads starting at 11 p.m. in preparation for the developing snow storm that's expected to drop 12-18" or more on the five boroughs. 

Included in the shutdown are all subways, buses, Metro-North trains, Long Island Rail Road trains and PATH trains.

City officials say non-emergency vehicles will be banned on city streets from 11 p.m. until further notice. Those caught out on the roads will be issued a summons and given a fine of up to $300.

This is the first time that the city's entire subway system has been shut down due to snow.  The system was previously shut down during Hurricane Sandy in 2012.

NY1 meteorologist John Davitt says he expects the storm to drop 12-18 inches or more on the city by morning, with the National Weather Service calling for up to 30 inches of accumulation. 

The bulk of the snow is expected to arrive between by 10 a.m. Tuesday.

Sanitation Commissioner Kathryn Garcia says crews will face 2 to 4 inches of snow per hour at times.

Mayor Bill de Blasio says city schools will be closed Tuesday and urged New Yorkers to stay off the roads tonight in preparation for blizzard-like conditions.

After-school activities including sports and adult education classes were canceled for Monday.

School Chancellor Carmen Fariña added that all of the canceled regents have been rescheduled for Thursday. Those regents include Global History and Geography, Integrated Algebra, Comprehensive Testing in Writing and Mathematics for special education students.

The Archdiocese of New York says its schools in the boroughs of Manhattan, Bronx and Staten Island will also be closed on Tuesday.

All CUNY schools will be closed Tuesday, though essential employees are expected to go to work.

The city has deployed 15 homeless outreach teams and is encouraging homeless New Yorkers to go to shelters during the storm. The shelters will be open to anyone who might be left stranded in the snow. 

New Yorkers are urged to call 311 for help, and 911 only in the case of life threatening emergencies.

The Visiting Nurse Service of New York is checking in on the homebound ahead of the blizzard to make sure they're prepared with enough medication, water, blankets, batteries, and non-perishable food for a few days. 

They say that seniors are at epecially high-risk for dehydration when the heat is turned on high. 

Those in need of assistance can contact the Visiting Nurse Service at 1-800-675-0391 or at vsny.org.

Governor Andrew Cuomo has also declared a State of Emergency for all New York City counties ahead of the storm and says the National Guard has been called out and stationed throughout the city and Long Island.  

The governor urged New Yorkers to put their safety first and avoid traveling on city roads and highways, adding that it is "not an evening or night to be out."

All Port Authority bridges will close at 11 p.m. Monday until further notice.

The worst of the storm is not expected to reach the city until after 10 p.m. but there will be precautions before then to make sure trains and buses do not get stranded.

The governor says major highways like the Long Island Expressway, I-84, and I-87 may be shut down as well.

Both the governor and mayor warned everyone not to underestimate the power of the storm.

The city Office of Emergency Management says all agencies have increased their staffing for the blizzard conditions, including 311 and 911 operators.

OEM says they are not expecting any flooding immediately after the storm since the temperatures will be in the 20s when it stops. 

They also advise construction companies to stop their work until the storm passes for safety precautions. 

The National Weather Service has issued a blizzard warning starting at 1 p.m. Monday and lasting until Tuesday at midnight.

The mayor says 2,400 employees who will work around the clock on 12-hour shifts and the city will deploy more than 1,000 snow plows. 

He says the storm is unpredictable but he urges people to stay off the roads because of conditions he says will be "treacherous."

The biggest snowfall ever recorded in New York City was 26.9" on February 11, 2006.

The city has closed all city parks as of 6 p.m.

Courts will be closed Tuesday in New York City and on Long Island, as well as in Dutchess, Orange, Putnam, Rockland and Westchester counties.

Alternate side parking is suspended through Wednesday.

Garbage and recycling collections will also be suspended.

Anyone with a heat or hot water problem should call 311.

At area airports, airlines are scrambling to reschedule customers, with more than 4,000 flights already canceled.

Thousands of flights have already been canceled going in and out of LaGuardia, JFK and Newark Liberty Airports.

All flights at LaGuardia are canceled Tuesday, and there will be only limited service at JFK.

Nearly every major airline in the U.S. and Canada is waiving change fees for customers flying to the Northeast.

The details vary by airline.

Most allow passengers flying to or through the Northeast can make one itinerary change without paying the standard change fee.

Air travelers should check with their individual carrier before heading to the airport.

Amtrak is warning riders about possible service disruptions.

Passengers with reservations to travel Monday and Tuesday should make any necessary changes well before they leave. They should also allow extra time when traveling and be careful around the stations and platforms. 

Amtrak says its diesel trains can help move electrical trains if downed trees disable the overhead electrical system.

On-track maintenance equipment can be dispatched to make any infrastructure repairs.

Independent contractors will also be on standby to respond to any reports of trees or limbs down along the right-of-way.

To check on your reservation and any service changes, call 800-872-7245 or go online to www.amtrak.com.

A list of some weather-related closings can be found here.

The snow has postponed both the Knicks game at Madison Square Garden and the Nets game at Barclays Center.

The Knicks game was rescheduled for March 3, while the Nets game was rescheduled for April 6.

All Broadway shows are canceled for Monday night.

Performances at Carnegie Hall and the Metropolitan Opera have also been canceled.