Warming overall- All that ice has now melted in the arctics, and for now we have too much moisture, actually having a counter-effect, and blocking the sun. Evaporating, causing clouds to block sun, raining and reforming- last two years after drought before that.
the winds HAVE shifted over the eastern half of U.S. where most of the population, air traffic, auto traffic and concrete is, sooooo,
north to south movement bring more EXTREMES in temperature, and MOISTURE that circulates back and forth between Gulf of mexico and Hudson Bay/ Great Lakes
In the west, the systems that come down in the winter along the coast from Alaska, haven't gotten as far south as strongly or frequently, for some time now, accounting for the longstanding drought in the Southwest.
Heres a little vid I shot about this:
YouTube - Cloud Seeding in the USA
Heres one of the "100 Year Flood" and seven feet of water that hit my house summer before last
http://www.youtube.com/watch?v=v0CP7FdSr98