What little I do know, our region has warmed faster than other areas, due to the slowing down of the Gulf Stream/Labrador currents circulation. That, combined with the menace of a Pacific Jet, has not left us a favorable snow situation. I understand that warmer air can feed more moisture into a winter storm, and thus producing more snow, but as you have mentioned, there is a tipping point. But I always fall back to a basic concept, the snow triangle (for the NYC metro area). Without a true cold air source, you can't have snow. I'm a pessimist, so my perspective is obscured. Patterns can change, and we might actually get true arctic air spilling down across the pole into eastern Canada. Or some "new" type of pattern could develop, but I tend to buy into the general warming trend unless some time of correction occurs (such as the theory of a rapid melting of the ice caps could cool down the oceans, thus causing a sudden swing back to a colder climate).