The most well-known mode of natural climate variability is the El Nino Southern Oscillation, an interannual climate oscillation originating in the tropical Pacific, but having effects around the world.
	The Atlantic lacks an interannual mode comparable to ENSO.  Instead, the dominant climate mode over the Atlantic is the NAO.  NAO is an oscillation involving the Azores High and Icelandic Low pressure centers and the westerly winds over the Atlantic.  It occurs in two states.  When the NAO is positive, the low and high pressure centers are intensified.  This leads to stronger westerlies that are shifted north.  This brings warm weather (stormy?) to northern Europe.  When the NAO is negative, the pressure cells diminish and the westerlies shift south.  Northern Europe is cold.