Biggest winter storm of season yet to unload travel-snarling snow, ice in Northeast

The weather system that has unleashed an all-out blizzard in parts of the north-central United States and deadly tornadoes in the South is far from finished. Next up, it will take aim at the Northeastern states, where it will unleash the most widespread snowfall across the region yet this season late this week. A dangerous ice storm will unfold in some areas as rain, wind and coastal hazards pelt the Eastern Seaboard.

The heaviest snow and ice will occur just north and west of the Interstate 95 major cities spanning Wednesday night to Saturday, AccuWeather meteorologists say. Accumulating snow will fall on approximately 200,000 square miles of the interior Northeast from a large portion of Pennsylvania to nearly all of Maine, causing significant disruptions as holiday travelers hit the road for Hanukkah celebrations, which begin on Sunday. Even in the rain zone along the East Coast, travel delays are likely due to wet roads, slick runways and poor visibility.

The first part of the storm began as ice from the central Appalachians to part of the mid-Atlantic region on Thursday.

AccuWeather forecasters have highlighted an area north and west of Washington, D.C., Baltimore and Philadelphia along long stretches of I-68, I-70, I-76 and I-81 from western Virginia to Pennsylvania for a buildup of ice. Where mostly freezing rain occurs instead of sleet, trees and power lines can be weighed down with the risk of blocked roads and power outages.

Nearly all of I-80 in Pennsylvania will be affected by wintry conditions from the storm. Already Thursday morning there were multiple accidents and lane closures on I-80 in central Pennsylvania.

Farther to the north in Pennsylvania, cold air is forecast to fight back soon after the storm gets underway. In this case, some locations will likely experience a wintry mix of sleet and freezing rain that will transition to all snow.

Where this changeover to snow occurs quickly, or where precipitation remains snow at the start, several inches to a foot or more of snow can pile up. Top amounts are most likely to accumulate from north-central and northeastern Pennsylvania to central Maine. Within this zone, pockets of heavier snowfall are likely due to the duration and intensity of the storm with an AccuWeather Local StormMax™ of 24 inches possible.

The snowstorm should treat ski resorts quite well from the Poconos to the Catskills and the Green and White mountains of the Northeast with plenty of natural powder and a solid base as the holiday season ramps up.

In distances well north of Philadelphia, just north and west of New York City and west of Boston, there will be a transition from rain to a wintry mix to all or mostly snow, which is often the case with a storm that tracks just off the Atlantic coast. Travel in these directions from the major cities will become progressively worse during the storm. The wintry mix zone may be just north of I-78 in Pennsylvania and New Jersey, west of I-278 around New York City and northwest of I-495 near Boston.

From Washington, D.C., to Philadelphia, New York City and Boston, rain will be the primary form of precipitation from the storm. Only if the storm shifts its position farther to the east, while moving northward, might there be a period of heavy snow in Boston.

Boston picked up its first measurable snow of the season on Sunday when just under an inch accumulated. Meanwhile, people in Manhattan had their first snowflakes from Sunday to Monday, when some of the surrounding boroughs picked up a tenth or two of an inch of snow. Philadelphia, Baltimore and Washington, D.C., have yet to be visited by snowflakes this season. Even if sleet occurs and 0.1 of an inch manages to accrue, then it will count as the first measurable snowfall in these cities.

Rain is likely to begin around New York City during the early afternoon hours on Thursday but should hold off until the middle of Thursday night in Boston.

The rain will pour down at a heavy rate and be accompanied by a period of gusty winds from the east and southeast. Heavy rain can lead to ponding on the highways with an increased risk of vehicles hydroplaning from the New York City area through southeastern New England. The combination of rain, wind and slick runways can lead to substantial airline delays and perhaps even a ground stop for a time.

The lengthy period of onshore winds can lead to minor flooding at times of high tide with the greatest tide anomalies of 2-3 feet possible in eastern New England on Friday.

Except for part of New England, this storm may not be a true nor'easter. A nor'easter is a storm along the East Coast of North America, so called because the winds over the coastal area are typically from the northeast, according to the National Weather Service. Winds in southern New England, the mid-Atlantic and central Appalachians are likely to blow from various directions during the storm.

In the wake of the storm, enough cold air will be drawn in from the Midwest to trigger bands of heavy lake-effect snow off of lakes Michigan, Erie and Ontario.

There is a likelihood of 6-12 inches of snow in the snow belts where the bands shift around this weekend. However, where these snow bands manage to persist, 1-3 feet of snow could pile up in some communities in parts of western and northern New York state.

The coldest air of the season so far and perhaps in decades for Christmastime is poised to invade the North Central states next week. The magnitude and eastward progress of that frigid air may depend on the evolution of a potentially major storm just prior to Christmas.

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