Why Was the Winter of 2012 So Warm?

by Conservation Chairman Bill Luther

Why was the temperature in North Dakota sitting at 54 degrees during the first week of January? Most of the warm weather which we basked in this winter can be attributed to the movement of the jet stream. The jet stream is in turn controlled by two atmospheric features called the North Atlantic and Arctic Oscillation. These oscillations reflect differences in sea level pressure across the globe. The winter of 2012 saw such positive pressure differences that warm air was drawn from the Southwest over much of the eastern seaboard. Storms that usually develop and produce snow were pushed out to sea. By contrast the winter of 2011 saw a huge negative pressure difference that allowed cold arctic air to drop down and seep into much of the US producing record snowfall. During the past six years there have been extreme positive and negative recordings of the Arctic Oscillation values in pressure.  Now that we know this, I’ll stop here and not talk about sunspots or global warming.