Snow Returns From Pennsylvania to NYC, Boston

By Alex Sosnowski, Expert Senior Meteorologist

January 15,2013; 8:50PM,EST

This week at least two storm systems will ride northeastward into the mid-Atlantic and New England with a wintry mix in some areas.
The first system brought relatively few problems across the region as mostly rain fell from Washington D.C into Philadelphia, New York and Boston.
There were a few reports of sleet mixing in with the rain, and there were a couple snow flakes on the northern fringe of precipitation, but there were no major travel problems.
The second of the two storm systems will arrive in the Northeast Tuesday night and depart Wednesday will still be considered a relatively minor event. However, it has the potential to be more significant than the first in that it has the best chance of bringing a wintry accumulation, comprised of mostly snow.

Colder air will continue to filter into the Northeast during the day Tuesday, setting the stage for a somewhat more broad area of frozen precipitation Tuesday night into Wednesday morning.

There is a better chance of some snow or a wintry mix reaching into the I-95 swath from near New York City to Boston with the second event.
Road surface temperatures may still be too warm for much, if any accumulation on the major highways in the I-95 region, except for north of Boston.
However, just enough wintry mix can fall just north and west of these cities for slippery travel.
Enough snow and wintry mix will fall during the late-night and morning hours from north-central Pennsylvania to interior New England to cause slippery travel. Major highways impacted include I-80, I-81,I-84, I-87, I-88. I-90, I-91 and I-93.
With the storm later Tuesday night into Wednesday, a general coating to an inch accumulation of mostly snow is possible on non-paved surfaces from part of southwestern Pennsylvania and perhaps western Maryland and the high ground of northern West Virginia to part of southeastern Pennsylvania, the nearby northern and western suburbs of New York to southern Connecticut, much of Rhode Island and southeastern Massachusetts.

The latest version of the snow accumulation map can be found on AccuWeather.com's Winter Weather Center.

Where mostly snow falls from central Pennsylvania to the Poconos, Catskills, Berkshire and northeastward through southeastern New Hampshire and much of coastal Maine, a general 1 to 3 inches is forecast with locally higher amounts in the higher elevations.
Odds favor rain again in the Philadelphia, Baltimore and Washington, D.C., areas with an increasing chance of slippery spots as you head into the distant northwestern suburbs of Philadelphia and toward the panhandles of West Virginia and Maryland.
Meteorologists call storms of this nature "flat waves of low pressure." In the right circumstances they can bring moderate to heavy precipitation. In the case this week, odds favor little or no precipitation with the first wave and light precipitation and the potential for moderate precipitation for some areas with the second wave.
Dry air will hold on over northern Ohio to northern upstate New York and northernmost New England.
Arctic air will overspread the Great Lakes, New England, neighboring Canada and upstate New York later in the week.
There is a chance a third wave of low pressure rides northeastward later this week. Odds favor this system passing off the southern Atlantic Coast before reaching much of the cold air up north.

Additional pushes of arctic air will tend to punch a bit farther to the south next week as the implications of the stratospheric warming event that occurred earlier in the month near the North Pole are realized.

---