Mayor Bill de Blasio announced Wednesday that all New York City public schools will be closed on Thursday, as city agencies and residents brace for a massive snowstorm.

The city is expected to get hit with anywhere between 8 and 12 inches of snow by Thursday evening, the National Weather Service said. A winter storm watch was issued for the five boroughs beginning at midnight Wednesday and lasting through 6 p.m. Thursday.

De Blasio urged city residents to not take the impending snowstorm lightly, adding that the city was prepared to deploy salt spreaders and plows to handle the expected snowfall.

“Regardless of how it feels like today, it’s going to be a full blown blizzard tomorrow morning,” de Blasio said in an interview with WCBS Newsradio 880 shortly after 2 p.m. Wednesday.

De Blasio asked commuters to stay off roads when possible, and rely on mass transit. 

Snow began falling by 6 a.m. Thursday after a mix of rain and snow in the early morning, the NWS said. It is expected to last until the afternoon, the agency said.

Scroll down to see how the city is preparing for the storm.

Department of Sanitation:

More than 1,600 snow plows and 689 salt spreaders will be deployed throughout the city. Salt spreaders were expected to start working as soon as the first flakes hit the ground and plows will start as soon as 2 inches of snow has fallen, said DSNY Commissioner Kathryn Garcia. 

“This will be a very dangerous storm,” Garcia said, speaking at the department’s Spring Street salt shed, adding: “Our focus across the city is to make sure that we are rolling out in a timely fashion.”

The department started the year with 375,000 tons of salt, and currently has more than 315,000 at the ready. A very large snowstorm typically uses 30,000 to 50,000 tons of salt, Garcia said. 

If the snow accumulation ends up being on the high end of the forecast, at 12 inches, Garcia said the department will “roll out” 134 front-end loaders. 

On Friday, she added, snow laborers will be dispatched throughout the city.

Subways and Buses: 

Express subway service on the 2, 3, 4, 5, A, B, E, D, F, N and Q trains ended early Wednesday night so the MTA could facilitate the underground storage of trains, according to Gov. Andrew M. Cuomo’s office. All previously planned maintenance, including FASTRACK, was canceled Wednesday night into Thursday.

Chains were being added to the tires of buses, but there will be a 20 percent reduction of local, limited, and SBS service for Thursday’s morning rush hour. 

Up to 2,900 snow-cleaning personnel will be on duty, working in 12-hour shifts during the storm. 

The system will be equipped with several pieces of technology, including more than 1,000 snow melting devices at switches, about 1,500 third rail heaters, and seven de-icer train cars. 

Parking:

Alternate side parking has been suspended for Thursday so that snow plows can go through. Parking meters will remain in effect. 

The Department of Transportation was pre-treating pedestrian overpasses and ensured ferry terminals and municipal parking garages were pre-salted, according to the Office of Emergency Management. 

But city officials are strongly encouraging people to leave their cars behind. 

“We want to keep the roads clear for the plows, we want them to do their work,” said Joseph Esposito, commissioner for the city’s Office of Emergency Management. “We really want to encourage you to take public transportation; give yourselves some extra time.” 

The department’s Situation Room was set to be activated at midnight to coordinate the city’s response.

Bridges and Tunnels:

More than 9,000 tons of roadway de-icer and more than 100 pieces of equipment, like trucks and plows, are available to clear the roads based on conditions, according to Cuomo’s office. A command center is monitoring conditions constantly. 

-With Laura Figueroa