There is a strong and established black middle class in several Southern cities: Raleigh/Durham, Atlanta, and New Orleans come to mind, but I'm sure there are others. I would guess that this is due in part to the large number of historically black colleges and universities down here. There are three in Raleigh/Durham alone: Shaw, St. Augustine's and NC Central. This -- and the nice weather -- is probably pretty attractive to a lot of black folks, no?
-WD