Wintry storm to bring December reality check to Northeast

Snow is forecast to return to part of the northeastern United States this weekend, but rain will fall on other areas and could dampen hopes for a white Christmas. Last-minute shoppers in the Northeast should have rain gear in hand and others may need an ice scraper if they plan on hitting stores on the last Saturday before Christmas, AccuWeather meteorologists say.

For snow lovers, it seems Old Man Winter has not been keeping up the fight, as record-challenging warmth surged into the Northeast this week, including across the typically coldest reaches of the region. However, those keeping the faith for snow and cold weather should be rewarded on Saturday, at least in portions of upstate New York and northern New England.

The same front that triggered fierce winds, with some topping 100 mph, as well as tornadoes in the Central states Wednesday blew through the Northeast with blustery conditions Thursday night and early Friday. Colder and more seasonable air behind the front will set the state for wintry conditions this weekend.

A storm will ride northeastward along the front on Saturday. The storm will produce wintry weather for some areas, but that will not be the case everywhere, including along much of the Interstate 95 corridor.

"Saturday can turn out wet with a cold rain for New York City with high temperatures in the 40s," AccuWeather Lead Long-Range Meteorologist Paul Pastelok said.

In Philadelphia, New York City, Pittsburgh and many of the towns, cities and rural areas from southern Pennsylvania and central New Jersey to Ohio on south, the storm will bring showers or a period or two of steadier rain for the first part of the weekend. Highs will generally be in the 40s in the central Appalachians, but temperatures are likely to push 60 in eastern Virginia.

A different story will unfold farther to the north in the region, however. Fresh cold air will dive in from the north ahead of this storm on Saturday, and precipitation will be more wintry with snow and ice expected across northern areas of the Northeast, Pastelok explained.

Snow will be the primary form of precipitation across much of Maine, Vermont, New Hampshire and northern New York state. This is because a thick layer of cold air in the atmosphere is anticipated. When there is a deep layer of cold air, snow that starts off in the clouds is able to survive the trip to the ground without melting.

"A general 3-6 inches of snow from northern New York state to much of Vermont, New Hampshire and Maine with pockets of 6-12 inches over the Adirondack, Green and White mountains," AccuWeather Senior Storm Warning Meteorologist Brian Wimer said. An AccuWeather Local StormMax™ of 15 inches is most likely over the ridges and peaks of these mountains into Saturday night.

The storm will bring several inches of accumulation to cities such as Glens Falls, New York; Burlington, Vermont; Lebanon, New Hampshire; and Bangor, Maine.

Boston could be right on the edge of the dividing line between rain and snow and could pick up a coating to an inch of accumulation before a complete changeover to rain. But if the milder air from the ocean that keeps precipitation in the form of rain to the southeast is slow to push west, or fails to do so at all, then the heavier snow over the northern and western suburbs could reach toward the coast.

Farther south, a shallow layer of cold air is likely to develop in the lowest part of the atmosphere, and conditions are likely to bring several hours of freezing rain on Saturday. The cold air will collect in the lowest few thousand feet and cause snow that melts higher up in the atmosphere to cool to near the freezing point. As soon as rain or drizzle hits a cold surface, it is likely to freeze.

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"The zone of freezing rain and drizzle is most likely to occur from the southern tier of New York to the northern tier of Pennsylvania, as well as the Poconos, northernmost New Jersey and even in parts of northern and western Connecticut and western and central Massachusetts," AccuWeather Senior Meteorologist Bill Deger said.

Ice and snow accumulation may be limited on some roads since it has been so warm, but slippery and dangerous conditions will not be prevented from developing everywhere.

"With this storm, a general 0.10 of an inch or so of ice is likely to accrue on elevated and grassy surfaces with local amounts to 0.25 of an inch over the southern tier of New York and the northern tier of Pennsylvania," Wimer said. He added that most highways at low elevations in this zone are likely to be wet, but over the mountains, in hilly areas and on bridges and overpasses, roads can be icy even if they appear wet.

People traveling over the high ground along Interstates 80, 81, 84 and 88, as well as Route 15 in northern Pennsylvania, should be prepared for icy stretches.

Sleet already began to fall across central Pennsylvania on Friday night, but it was melting quickly on roads and decks of homes.

With a few exceptions, not enough ice is likely to build up on trees and power lines to cause power outages. During the afternoon hours on Saturday, the air temperature may inch above freezing in much of the region, ice will stop developing and should begin to melt in most places.

From part of central New York to the southern parts of Vermont, New Hampshire and Maine, just enough warm air may sneak in to allow snow to change to a wintry mix for a time later Saturday, before the storm departs. Any wintry mix in this zone may cut down on snowfall accumulations.

Looking ahead, the overall pattern is likely to remain favorable for seasonable cold to dominate and an active storm track across the northern tier of the Central and Eastern states through Christmas weekend.

"There can be a couple of disturbances producing snow showers across the Great Lakes and interior Northeast next week," Pastelok said. Temperatures across much of the Northeast next week look to be typical of December. That could result in an increase in heating demand, especially after the warmth experienced much of this week.

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