Blizzard to Nail Long Island; Heavy Snow for NYC

By Alex Sosnowski, Expert Senior Meteorologist

February 7,2013; 7:26PM,EST

New York City and the northern mid-Atlantic are on the edge of a major storm that will hit New England as a blizzard Friday and Friday night.

The storm will bring at least several inches of snow and a period of high winds from central New Jersey to the lower Hudson Valley.
Even though the area from central New Jersey to southeastern New York state may not be in the epicenter of this storm, enough snow will fall to cause major travel problems and winds can be strong enough for a time to cause downed tree limbs and sporadic power outages.

Only if two storms, an Alberta Clipper from the west and a storm from the South, merge very quickly will there be more than a manageable amount of snow in New York City, northern New Jersey, southwestern Connecticut, Long Island, northeastern Pennsylvania and upstate New York.

That faster merge of the two storms would translate to a foot or more of heavy, wet snow around New York City, western Long Island, the lower Hudson Valley and northern New Jersey. Essentially in this case, much heavier snow could fall west of I-91 in Connecticut to just east of I-81 in northeastern Pennsylvania with I-87 in the middle. Much of central and southern New England would still be clobbered by one to two feet of snow, but rain would be even more of a player than now portrayed in southeastern New England and Cape Cod.

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According to Winter Weather Expert Rob Miller, "While this is a possibility, it would be difficult for a storm to do this without a blocking area of high pressure to the northeast."
Such an area of high pressure would slow the forward speed of the storm down long enough to cause it to strengthen into an intense area of low pressure.
Warm air will be the issue in the New York City metropolitan area and Long Island causing part of the storm to be rain, a wintry mix and some of the snow to melt as it falls on roads during the first part of the storm.

Odds favor wet roads around the New York City to a few slippery spots north and west for morning rush hour Friday. However, as more snow starts to mix in later in the day and a change to all snow likely by Friday evening, road conditions could rapidly deteriorate for the drive home Friday. The worst of the storm in New York City and nearby areas would be during the first part of Friday night.
Low cloud ceilings and increasing winds during Friday may lead to building flight delays and cancellations even if snow were to stay away from the several major airports in the New York City area.

Just as there is the possibility of the storm strengthening rapidly to bring heavy snow to New York City, there is also the chance the storms stay separate long enough so that little precipitation falls. AccuWeather.com meteorologists are meeting the odds in the middle, projecting 6 to 12 inches of snow in New York City, preceded by rain or a wintry mix during much of the day Friday.

Farther south, the warm air may bring all or mostly rain to Philadelphia, Baltimore, Washington, D.C., southern New Jersey, the Delmarva Peninsula, much of the Maryland mainland and much of Virginia.
Depending on the speed of the merger of the two storms, a few inches of snow could fall on parts of southeastern Pennsylvania and southern New Jersey. Regardless of how quickly the two storms come together, at least several inches of snow will fall over northeastern Pennsylvania, northern New Jersey and southeastern New York state.

The southern part of the storm will drench the south with beneficial rain, but also urban flooding problems and locally strong thunderstorms Wednesday night into Friday.

Long Island is a unique spot as the area will likely be far enough to the east Friday night as to enter into the 2- to 4- inch per hour snow as the storm intensifies before pulling away. If the storm manages this for a few hours, there would be not only blizzard conditions, but over a foot of snow in some areas.
The strongest winds will be blowing offshore as the storm strengthens. However, there may be some minor flooding problems along the north shore of Long Island with tides running up to a couple of feet of published values.

The greatest risk of coastal flooding from the storm is along the east coast of New England (from Cape Cod to Boston). The high tide cycle Friday evening is likely to be the most troublesome for northern Long Island. That high tide is within a couple of days of the new moon, which is early Sunday morning.

In the central Appalachians, most areas will be south (and north) of the heavy precipitation, with a punch of dry air from the southwest being a factor, and warm enough for rain or a wintry mix for at least part of the event.
Across upstate New York and part of southern Ontario, moderate snow will fall from a substantial Alberta Clipper cruising in from the Midwest Friday into Friday night.

For more information on the Alberta Clipper snow affecting the Midwest Thursday night and Friday, a new story has been published on AccuWeather.com.

Enough snow to shovel and plow is likely over much of this area which can reach as far south as parts of western and northern Pennsylvania into the higher elevations of West Virginia and western Maryland.
A brief shot of blustery, seasonably cold conditions are in store for Saturday in the wake of the storm. Temperatures will moderate Sunday, setting the stage for the next storm system Monday to bring mostly rain to the region with a wintry mix over northern upstate New York and northern New England.
The atmosphere is in the process of building a pipeline of storms for the eastern part of the nation during the balance of February. Most will bring rain to the mid-Atlantic coast, but some could bring snow. Details will follow as the time draws nearer.
This story was originally published at 11:00 a.m. EST, on Wed., Feb. 6, 2013 and has been updated.