Warm(er) air is more conducive to snowfall because warm air holds more moisture. But without those cold arctic and polar fronts bringing freezing temperatures, the snow doesn't happen. Likewise, you need a water source. Whether it is a lake, river or ocean. The Gulf of Mexico and Atlantic-based lows bring in water over top the cold airmass. Many storms lose moisture as they ascend over mountainous regions. In essence they dry out. Many storms that start near lakes will not produce very much snow the farther from that lake or lakes.
But to say that it is global warming that is accounting for these snowfalls, is a reach. Things like a descending or ascending jet stream, an upper air trough, a vorticity max or some other disturbance is what causes the lift necessary to produce clouds, which produces the chance for rain.
These outbreaks, whether cold or warm are not necessarily a harbinger of any global trend, but more than likely, part of a long term cyclical process, that has more to do with the exchange of heat between oceans and the surrounding sea surfaces and atmosphere...
JS- you just proved my point. It is warm air mixing with colder that produces this kind of snow. it takes moisture and that comes from ocean bodies, generally for this kind of event. It is plainly evident, that most here know so little about climate and weather. The ones who claim this is all junk science, has it right
Meteorologist Mike Scott