NEW YORK (CBSNewYork/AP) — Mayor Bill de Blasio declared a state of emergency for the city effective at midnight Monday night, as a massive and dangerous snowstorm bore down on the area.

“We’re going to be hit with a tremendous challenge in the coming hours,” de Blasio said.

De Blasio said the city expects the worst of the situation to be in the early morning hours. Snow is expected to begin between midnight and 1 a.m., with the most intensive accumulation beginning between 5 a.m. and 6 a.m., and continuing at a very high level for hours thereafter.

“We expect this storm overall to be in the range of 16 inches to 20 inches of snow,” with a high end of up to 24 inches, de Blasio said.

Late Tuesday night, the trajectory of the system and where the bands were to set up remained in flux.

All above-ground Metropolitan Transportation Authority subway service will be shut down beginning at 4 a.m. Tuesday as the dangerous snowstorm blows into the area.

Trains underground are still scheduled to run. A final decision will be made by 4:30 a.m. Tuesday for the Long Island Rail Road and the Metro-North Railroad.

Gov. Andrew Cuomo made the decision to close the subways above ground. But as WCBS 880’s Alex Silverman reported, de Blasio took no issue with the decision.

“We agree with that decision, but obviously want to see real coordination before any decision on a travel ban or anything like that,” he said.

MTA bus service will continue to run, but Mayor Bill de Blasio said it will be reduced by as much as 30 percent. City bus services could be suspended based on road conditions.

Commuters from around the area were making other plans.

“I just try to find anything that’s working at the time during tomorrow,” said commuter Rayquan Hodges. “… It will probably be more of a hassle.”

The mayor also said it is a real possibility that driving will be banned on city streets, as has been ordered in past blizzards. But he is waiting for a late-night weather update.

But as CBS2’s Tracee Carrasco reported, cab driver Durvir Singh said regardless of the storm, he will be out on the road.

“I’ve been doing this for 20 years, so I’ve been through many, many storms,” Singh said, “so I work every time.”

New York City public schools will also be closed Tuesday, Mayor Bill de Blasio said. A powerful nor’easter that could bring blizzard conditions and more than a foot of snow moves in.

“This is an unusually early call, but we’re seeing this snowstorm hitting exactly at the time when parents will be trying to move around with their children,” de Blasio said.

De Blasio said giving an early heads up will give parents time to find appropriate child care. But for some, it is a snow day for parent and child.

“I was excited,” said mother Robin Morris. “I was like, ‘Yes! No work no school tomorrow!’ It was a blessing.”

“I was like yeah, because I’m going to sit on my couch and play Xbox 1,” said Eliza Morris, who added that she was not interested in playing in the snow.

Some parents were not as excited about the idea as the children.

“Most likely, their mom is probably going to be stuck with them, so good luck to her,” said city schools father Greg Mitchell.

Mitchell’s children, on the other hand, can’t wait.

The City University of New York announced on Twitter that its colleges and university offices will be closed.

At Columbia University, most university events were expected to be canceled due to the storm. Butler Library will be open only as study space, and Dodge Fitness Center will be open along with JJ’s Place at John Jay Dining Hall.

The NYU campus will be closed – and all day and evening classes will be called off Tuesday unless specifically communicated otherwise.

A blizzard warning is in effect for the entire Tri-State Area, as well as areas as far south as Philadelphia, from Monday night through Tuesday night.

CBS2’s Lonnie Quinn reported all the scenarios that were expected to make for a major blizzard have come together.

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Beginning at midnight, the state of New York will also be under a state of emergency issued by Gov. Cuomo. A state of emergency has also been declared for New Jersey by Gov. Chris Christie.

But snow was set to begin falling after midnight and conditions will begin turning gusty.

Light snow was beginning in some areas Monday night was set to intensify overnight into early Tuesday morning. The heaviest snowfall is expected Tuesday morning through the afternoon, with snowfall rates of as much as 2 to 4 inches per hour.

By 7 a.m., 2 to 5 inches of snow may be on the ground.

On Tuesday morning, there will be heavy, blowing snow, gusty winds and coastal flooding, with 8 to 12 inches of accumulation.

By 1 p.m. Tuesday, wind gusts were expected to top out at 51 mph in the city; 58 in Westport, Connecticut; 60 in Sea Cliff; 69 in Coram; and 78 in Montauk.

By late in the day, 12 to 18 inches of snow could be on the ground if not more in many areas. The biggest snow totals are expected to be seen north and west of the city, while the highest winds will be seen to the south and east.

But the exact path of the storm remained in dispute late Monday.

New models show the snow mixing with sleet in portions of New York City proper, and rain for parts of Long Island and Ocean County.

As of 11 p.m., computer models disagreed on what was likely to happen. The PM showed 14.6 inches for the city, 20.7 inches for Poughkeepsie, 23.3 inches for Montgomery, and 24.1 inches for Monticello – but only 2.5 inches for Brick, New Jersey.

The North American Mesoscale Model anticipates the mixed precipitation coming closer to the city – calling for a mere 6.2 inches of snow in the city and 0.6 inch in Brick. But the model called for staggering totals to the north and west – 25.9 inches in Sparta, 27.5 inches in Poughkeepsie, 29.5 inches in Montgomery, and 32.4 inches in Monticello.

Quinn continued to forecast that most of the area would likely see 12 to 18 inches, while areas to the north and west could see 18 to 24 inches.

De Blasio advised advised to stay off the roads and keep them clear for emergency vehicles.

The Weather Service also said there could be whiteout conditions at times and power outages.

As CBS2’s Alice Gainer reported, Mayor de Blasio said because there have not been too many winter weather days this season, there is quite a bit of rock salt ready for the storm. About 283,000 tons are on hand.

“It’s a very important point – for your own safety, given the frigid temperatures; the huge amount of snow in a short period of time; the wind… stay off the streets,” de Blasio said.

Beginning Monday night, Department of Sanitation teams will start 12-hour split shifts beginning at 7 p.m. there will be 2,400 sanitation workers per shift.

A total of 689 salt spreaders have been pre-deployed.

As soon as 2 inches of snow are on the ground, 1,600 plows will go into action – and the Department of Sanitation will add an additional 80 plows to that.

Once the snow accumulates, plows will be out constantly – but that doesn’t mean they can make the situation normal.

“Because of the intensive accumulation, do not expect to see blacktop for quite a while as we go through the day tomorrow,” de Blasio said.

The Sanitation Department said the garbage and recycling collections will be suspended once the snow begins. Alternate-side parking for Tuesday and Wednesday have also been canceled.

Residents were crowding local grocery stores like Trader Joe’s on Broadway off 72nd Street on the Upper West Side, scrambling to pick up last-minute items.

“I got water, and salad — and tater tots,” one woman told WCBS 880’s Alex Silverman. “Which is a full meal if you ask me.”

A line of grocery shoppers was also seen outside of the Trader Joe’s in Kips Bay. The customers there were hoping for better luck than those at a Home Depot in Chelsea, which had empty pallets of salt and only a handful of shovels left late Monday.

Monday morning, Gov. Cuomo activated the state’s Emergency Operations Center and said he has directed state agencies “to continue proactively preparing communities and roadways for this major storm.”

“We remain in constant contact with local officials in every region, as New York prepares to aggressively clear roads, provide personnel and storm equipment as needed, and offer immediate assistance to communities across the state,” he said in a statement. “I strongly urge everyone to limit unnecessary travel on Tuesday, and if you must drive, please plan ahead, be careful and stay safe.”

If you have got a heat and hot water problem, you are asked to call 311 and take care of it on Tuesday.

There will also be a Code Blue effort to get people off the streets, out of the cold, and into shelters.

The Department of Buildings is also advising property owners, contractors, and crane operators to take precautionary measures and said all cranes must be secured Monday.

The Citi Bike system will also shut down effective at 11 p.m. Monday in advance of the snow.

Forecasters say there also could be minor to moderate coastal flooding on Tuesday.

Winter’s big return arrives just a week after the region saw temperatures climb in the 60s.

(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)

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