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Flight information is seen on a screen at a terminal of JFK International Airport in New York, the United States, on March 21, 2018. Thousands of flights were canceled and public schools were closed as the fourth snowstorm in three weeks began hitting New York City and its neighboring areas on Wednesday. (Xinhua/Wang Ying)

NEW YORK, March 21 (Xinhua) -- Thousands of flights were canceled and public schools were closed as the fourth snow storm in three weeks began hitting New York City and its neighboring areas on Wednesday.

The New York City Department of Sanitation has issued a snow alert, and the heavy wet snow is expected to intensify throughout the day.

Alternate Side Parking regulations will be suspended on Wednesday and Thursday. Commuters are advised to use mass transit where possible.

New York City Mayor Bill de Blasio announced Tuesday that the city's public schools will be closed Wednesday due to the storm.

More than 2,000 flights, including those from the Chinese city of Shanghai to New York, were already canceled on Tuesday evening at the three major airports that serve New York.

The bulk of the dangerous, wind-driven snow and sleet is also expected to wallop the states of Maryland, Delaware and parts of eastern Pennsylvania.

New Jersey Governor Phil Murphy declared Tuesday a State of Emergency, authorizing the state director of emergency management to activate and coordinate response and recovery efforts. State offices will be closed Wednesday in Murphy's order.

New Jersey State Police issued a commercial vehicle travel ban for the entire length of highways including I-78, I-80, I-280, and I-287.

It is the fourth northeaster in three weeks, with many people across the region still reeling from the first three that downed trees and power lines and left tens of thousands of residents in the dark.

New York City's northern suburbs and the neighboring state of New Jersey were the worst hit during the first two snow storms, while the third took aim at the coastal state of Connecticut and the shores of Long Island off the East Coast.