So reports the Daily Tar Heel, based upon research by an N.C. State linguistics professor. The key point:

Although the main stimulant of the withdrawal of the Southern accent came with new people, existing residents also changed their dialect, [ N.C. State associate professor of linguistics Robin Dodsworth]  said. A bad connotation started to accompany the Southern drawl, and as a result, some younger Raleigh residents might try not to speak with a Southern accent.

The next step in the research is to extend the study to Charlotte.

H/t: JMH