Sandy had some effect, though NY and NJ would probably still have trended D. I wonder if the LA and MS swings can be partially explained by Sandy reminding people about Katrina, and how Republicans botch natural disasters.
Trended is one thing. For Obama to get SWINGS in the affluant white counties of NY and NJ when the country as a whole swung about 4 pts the other way, and the GOP candidate was Mitt Romney, shows that another factor was at play.
Interesting point about MS and LA. Louisiana shocked me, I thought for sure Obama was set to erode even more. Mississippi is a little more understandable, as black voters made up a greater % of the voting populace.