"Actually a lot of it, in all the NE is folks moving south and west for better jobs, and Boomers cashing out in the overheated real estate markets and moving where its warmer and cheaper to retire."
These trends tend to reverse themselves, though. I have to believe that New England states will be doing all they can to encourage people to stay, if for no other reason then to maintain their political clout.
Oh they will try, but they won't win the battle... no more than the midwest was able to keep folks from moving south and west when the factories closed.
1000 to 2000 folks a week are moving to the TAMPA area right now, alone and its not going to change anytime soon.
Overvalued real estate, hard winters... lots of folks can cash out for huge paydays, go buy a nice house on the cheap for what they are used to, and live the rest of their lives comfortably just on the sale of their home, let alone whatever else they have saved up.