Editorial: Buried under snow, Washington, D.C., and other mid-Atlantic regions have become showpieces for the folks who want to dispute the possibility of global warming. Not so much here, though, where southeast Michigan has tromped through a winter that has been extraordinarily … average. At 30 inches as of Friday, measured snowfall is 2.3 inches below normal; temperatures are running a bit above normal, including this month, which is 0.6 degrees warmer than average to date. And then there’s …