"The transformation in Virginia’s statewide partisan lean is the product of some major changes in the voting habits in different parts of the commonwealth. If we take a step down from the statewide level, we can start to really see these shifts by looking at Virginia’s three major metropolitan areas and the parts of the state that lie outside of them."

http://www.centerforpolitics.org/crystalball/articles/the-new-dominion-virginias-ever-changing-electoral-map/