In Raleigh-Durham (#25), the stay is usually brief as reporters jump to even larger markets.
At top rated CBS affiliate WRAL-TV (one of the few remaining locally-owned Top 25 market stations), the evening news anchor team of David Crabtree and Pam Saulsby has been in place since 1994, when Crabtree took the place of longtime anchor Charlie Gaddy. Saulsby's been at WRAL since 1991. Morning and noon news anchor Bill Leslie has been at the station since 1984. Chief meterologist Greg Fishel just celebrated 30 years with the station, though he's only been chief since 1989 or so. Tom Suiter was the evening sports anchor from 1981 until a year or two ago when he ceded the chair for other projects (he started with WRAL in 1971). Among reporters, Amanda Lamb has the most seniority, having started in 1994.
At ABC O&O WTVD, the perennially second-place station, Larry Stogner is the market's senior news anchor, having held that chair for 29 years, following six years as a reporter. Two WTVD reporters have been there a long while as well, Fayetteville Bureau Chief Greg Barnes (1983) and Senior Reporter Ed Crump (1984). As for their weather and (especially) sports teams, you won't find a great deal of seniority, save for chief meterololgist Chris Hohmann (started in the mid-90s).
At distant-third place WNCN (NBC 17), which has only been in the news business since 1995, there has been such heavy turnover that none of the original team is still there. Morning meteorologist Bill Reh was at WTVD from 1984 into the mid/late 90s, then at the now-defunct news operation of WLFL-TV 22, before coming to WNCN. Anchor/ Kim Genardo has been there since 2000/2001.