A powerful winter storm that hit the Mid-Atlantic Friday may dump up to half a foot of snow on Long Island and the metropolitan region -- or we may wind up with just a dusting, forecasters at the National Weather Service said.

As of Friday afternoon, a Winter Storm Watch remains in effect for 6 p.m. Friday through Saturday afternoon, meaning there is a potential for "significant snow that may impact travel," according to the National Weather Service.

Forecasters are saying there is a potential for 4 to 8 inches in the tri-state area, but it is still uncertain how much snow Long Island will see because a small deviation in the storm's track will have a significant impact on its severity.

Snow is expected to begin falling late this evening and continue into Saturday before tapering off later in the day, forecasters said.

MORE: LIRR may shut down if storm is too big

Mayor Michael Bloomberg said on his weekly radio show Friday that New York City is "on the ready," with salt spreaders and plows positioned to go.

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Washington, DC was preparing for as much as 30 inches of snow.

Airlines canceled flights across the region and school districts closed for the day ahead of heavy, wet snow forecast from Virginia and West Virginia across Maryland into southern New Jersey and Pennsylvania.

The National Weather Service issued a warning stretching from Baltimore to northern Virginia and parts of West Virginia.

The weather service warns that the mix of heavy snow and strong winds would make travel Friday night “very hazardous or nearly impossible.”

The storm may pass well south of Long Island or portions of it may hit the area, forecasters said.

The Associated Press contributed to this story.

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