There has been a persistent, re-occurring weather pattern where a huge trough lodges itself over the eastern third of the country, and a huge dome of high pressure lodges itself over the western U.S. The result is extreme heat and summer-like conditions for the west, and cooler than normal, unsettled weather for the east, particularly the mid-Atlantic states. As an avid motorcyclist who loves to night-ride, it suffices to say that the summer of 2017 was a huge disappointment. Unfortunately, the latter part of the summer of 2018 looks to be no better. This pattern is not new, it is reminiscent of a similar pattern that re-occurred during the summers of 2000 - 2004. We broke out of it in 2005 and for the late 2000s and early 2010s we had more normal summer weather for our region. So my question is this: Does this pattern repeat every so many years, and what is the fundamental underlying cause of the pattern? Is it caused by warmer/cooler than normal water temperatures over the Atlantic/Pacific? Is there a tropical ocean temperature anomaly that causes this? (el nino, la nina)? Or is the cause of this weather pattern basically unknown?