Warm air rises, cold air sinks. When the warm air rises, it condenses into precipitation and since it’s moving into a cold air mass, the precip falls as snow.
This is not going to be 2016 imo. This could be a big storm but that was historic. If you are expecting 2016 then you are setting yourself up for disappointment.
I guess it depends on where you are. GFS actually shows more snow north of DC than the Euro. I guess GFS is a disaster for areas to the south that got a foot on the Euro. DC Beltway areas do about the same (4-6) on both models, although more upside potential with the Euro.