Local TV stations around the U.S. are expanding their news programming - or at least their length. News has long been the primary source of local TV production efforts, providing stations programs where they control the amount of commercial time, and the ability to sell all of it. (Network programming and much syndication programming split commercial time with local stations). When you also see that local TV is consistently identified as a primary news source, it's easy to understand that local news programming provides much of the local revenues for stations.
While local TV took a revenue hit in the last couple of years, along with other media, revenues are increasing this year, and the added demand for TV ad spots that the 2012 election cycle has analysts projecting a continued recovery for local broadcasting. Expanding the hours of local news lets stations add to commercial spot inventory, and the election cycle will also bring a lot of opportunity for low-cost stories. While research shows some expansion of news staffing, a lot of the expanded hours recycles news stories, has much more "chatter" between anchors and reporters, and soft news. A FCC study earlier this year found instances of excellence, but concluded that a emphasis on weather, sports, and crime - and it's unlikely that the expanded hours of news programming will change that.
Sources - Local TV Newscasts Expanding New York Times
The Information Needs of Communities: The changing media landscape in a broadband age. Chapter 3: Television FCC Report