CNN CNN Saturday Morning December 21, 2013 15:58:00
Coast-to-coast, impacting tens of millions of people. what's the science behind all of the extreme weather? >> in terms of the storms we've seen in october, november, december, as i often tell peo e people, you know, the atmosphere doesn't have an on-off switch that knows when winter begins. >> dr. marshall shepherd is a president of the meteorological society. he said there's one big reason for the wild weather, the jet team. >> when we have the el nino-neutral conditions, the jet stream patterns, we get the strong dips in the jet stream patterns, and in the dips, cold air, and in the hills, ...