This is just my own opinion, but I don't think there is really any merit to seasonal snowfall forecasting (and the same goes with tornadoes)...now you can certainly do something along the lines of a probabilistic standpoint indicating likelihood of above-average, around average, and below-average...but doing so by a range of totals...I don't think there is any skill or merit to it. There are way too many factors involved which you simply can't forecast (outside of short-term) and can't correlate to a specific pattern...one of them being how much snow a system can potentially produce.