New York Mayor Michael Bloomberg late Tuesday issued a weather emergency as a large storm, arriving just weeks after a massive snowfall paralyzed the region, was set to strike the northeastern United States.

Bloomberg was harshly criticized for the city's slow response to the post-Christmas blizzard, when nearly two feet (61 centimeters) of snow fell in the area.

New York did not declare an emergency for the December 26-28 blizzard -- but this time Bloomberg is taking no chances.

The declaration, issued by the city's Office of Emergency Management, urges drivers to stay off the road and use public transportation wherever possible, and allows tow trucks to remove "at the owner?s expense" any vehicle blocking a road or preventing snow plows from cleaning streets.

The weather emergency declaration however is not as sweeping as a "snow emergency," which allows only cars with chains or snow tires on major roads, and lets police ticket and tow cars parked on major streets.

The US National Weather Service said that two low pressure systems, one heading up the eastern US seaboard and another moving in from the Ohio and Tennessee valleys, are set to merge off the mid-Atlantic coast and rapidly intensify.

A wintry mix "is expected to become mainly snow, spreading northward into New England (late Tuesday) and becoming heavy in coastal areas from New Jersey northward," the Weather Service said on its 2100 GMT advisory.