I'm not much of a fan of long-range outlooks--meteorology is not much more capable than guesswork for a period longer than 5-12 days, depending on the weather pattern--but this is worth reading.

It's the winter outlook from the National Weather Service. You can take or leave the specific predictions. But it does an excellent job of explaining some of the factors that would influence winter weather. Specifically, one important driver is the North Atlantic Oscillation (NAO). When the NAO is positive, that allows the jet stream to retreat up into Canada, carrying cold air to the east, north of NYC. When the NAO is negative, cold air is forced down into the Eastern U.S., setting up cold outbreaks and a greater potential for snowstorms.

The discussion also makes the important point that an "average" winter still means lots of fluctuations: cold outbreaks, warm spells, dry periods and snowy times. Most of weather is, in fact, above or below normal; "normal" is simply the mathematical average of all these variations combined.