A storm system is expected to dump more than a half a foot of heavy, wet snow in the New York region, causing widespread school closures and a potential commuting nightmare.

“This is going to be a serious storm,” said New York City Mayor Bill de Blasio as he urged New Yorkers who did not need to use their cars in the morning to stay off the roads to allow snowplows to do their work. “We’re going to have very messy conditions, slippery conditions, dangerous conditions.”

A winter storm warning is in effect until 7 a.m. Monday in New York City, the lower Hudson Valley, northeastern New Jersey, and southwest and coastal Connecticut.

Weather officials expect moderate to heavy wet snow along with some sleet and freezing rain toward the southern coasts. Six to 8 inches of snow is expected. The heaviest snowfall should come between 9 p.m. Sunday and 4 a.m. Monday.

“People should be ready for really tough conditions in the morning even though right now in a lot of the city all you’re seeing is rain — that’s going to convert to snow soon, and we expect, as the night goes on, the snow is going to pick up and it’s going to get more and more intense right before the morning rush hour,” de Blasio said.

New York City schools will be closed Monday and alternate side parking was suspended for Monday and Tuesday. A hazardous travel advisory is in effect in New York City through Monday.

The city’s Department of Sanitation said it has 1,600 plows and has loaded 695 salt spreaders across the five boroughs and will begin plowing when more than 2 inches of snow accumulates on roadways.

“The critical time of the snowfall is on the overnight,” said Emergency Management Commissioner Joseph Esposito. “But I think our most critical time will be tomorrow’s rush hour..that’s why we’re urging people stay off the roads.”

The storm is hitting New York City just as it finishes up clearing Saturday’s snowfall, which dumped four inches in Central Park.

Meanwhile, NJ Gov. Phil Murphy declared a State of Emergency Sunday afternoon, deploying about 2,500 plows and salt spreaders across the state’s roadways in preparation for a storm that is expected to drop as much as 8 inches of snow in the northern half of the Garden State.

A shift in the storm has forecasters anticipating less snow in Ocean and Monmouth counties, where 4 to 6 inches could accumulate.

Alternate side parking will be canceled tomorrow, Monday, March 4th until Wednesday, March 6th so @NYCSanitation can work on snow operations. pic.twitter.com/Ewlb5zMPfN

— Mayor Bill de Blasio (@NYCMayor) March 3, 2019

We're expecting more snowfall this evening into tomorrow morning, so plan ahead! Forecasts predict 4-7 inches. Expect slick conditions on the roads and use mass transit if possible. Follow @NotifyNYC for updates on conditions. pic.twitter.com/T2qQuBY8zz

— NYC Mayor's Office (@NYCMayorsOffice) March 3, 2019

CORRECTED [415 pm 3/3/2019] Precip moving into W areas. Much of the precip is evaporating before it hits the ground, but a flurry or sprinkle is possible across NYC, NE NJ, and the Lower Hudson Valley.

Generally, 4″- 8″ most areas, 8″- 12″ possible across central and eastern CT. pic.twitter.com/bKupxPcxBu

— NWS New York NY (@NWSNewYorkNY) March 3, 2019

Precipitation, both rain and snow, is overspreading the area. The latest snowfall forecast is below. Your reports are greatly appreciated! We see them, but we can’t always respond to all of them. Be very cautious if traveling through tonight! #NJwx #PAwx #DEwx #MDwx pic.twitter.com/A0sYwSDKZN

— NWS Mount Holly (@NWS_MountHolly) March 3, 2019

(AP / YWN World Headquarters – NYC)