Wintry Mix from Interior Pennsylvania to NYC, Boston

By Alex Sosnowski, Expert Senior Meteorologist

January 14,2013; 2:04PM,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.

Two systems will be impacting part of the interior South through Tuesday with areas of ice and a wintry mix.

Not enough cold air will be in place or the air will be too dry in the Northeast for major problems with the first storm system. However, there could be some exceptions.
In the northeastern part of the nation, the first event will bring some rain from southern West Virginia and southwestern Virginia to Long Island Monday night into the first thing Tuesday.
Just northwest of this zone, the air will be cold enough at various layers in the atmosphere to support spotty rain that can freeze on some surfaces, as well as a dash of sleet. This is possible from southern Ohio and northern West Virginia to western and central Maryland, northernmost Virginia, part of Pennsylvania, northern New Jersey and perhaps the northern suburbs of New York and part of western Connecticut.

Odds favor relatively few problems with the first event, due to the very spotty nature of the precipitation, recent warmth and marginal temperatures during the event. However, even a thin coating of ice can make for very dangerous conditions, especially on bridges and overpasses that tend to cool off faster than other areas.
The second of the two storm systems arriving in the Northeast later Tuesday/Tuesday night and departing early Wednesday would still be considered a minor event. However, it has the potential to be more significant than the first in that it has the best chance of bringing an accumulation, compromised 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 and perhaps the nearby Philadelphia suburbs 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. However, just enough wintry mix can fall just north and west of these cities for slippery travel.
With the second storm, a general coating to an inch or two 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 the lower Hudson Valley of New York, central and northern Connecticut, central and western Massachusetts and the southern parts of Vermont, New Hampshire and Maine.

A wintry mix including snow, sleet and freezing rain is upcoming for a swath in the Northeast from two events before Wednesday afternoon. (Photos.com image and thumbnails)

Odds favor rain for both events in the Baltimore and Washington, D.C., areas with an increasing chance of slippery spots as you head into the distant northwestern suburbs.
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.
During both events, dry air will hold on over northern Ohio to northern upstate New York and northern 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 from the South.

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.