Scientific American: WEIRD WINTER: The record-breaking snowfalls of 2009-10 in the eastern U.S. resulted from the combination of two periodic weather phenomena, experts say. Just six months ago residents of the eastern U.S. were shoveling themselves out of the snowiest winter ever–weather that prompted mockery of global warming among some people. Now, scientists have a new explanation for why such anomalous snowstorms can coexist with global warming: The storms were kicked up by the convergence of two …