NBC Universal, along with Bain Capital and The Blackstone Group, has agreed to acquire The Weather Channel from Landmark Communications for a figure reported to be $3.5 billion. The deal is the first of several sell-offs for Landmark, which also hopes to sell Dominion Enterprises, a classified giant, and The Virginian Pilot newspaper in southern Virginia.

Landmark had apparently been hoping to get $6 billion for The Weather Channel, which was launched 26 years ago and includes Weather.com, Weather Services International and a maker of weather radar systems. The Weather Channel’s content is seen on thousands of sites and broadcast stations that syndicate it.

NBCU actually already owns a minor weather service. But one of the key attractions of owning The Weather Channel is the high volume of targeted business travel and local traffic it receives. Everything on the channel and the Web site is geotargeted by city name or ZIP code. By some measures, in fact, Weather.com is one of the biggest “local” sites. Theoretically, Weather.com could be combined with other high-volume local verticals such as sports and news to form the foundation of a powerful set of content that can work as a destination and as a syndicated package on other sites. NBCU’s various sales channels could also be put to work.

Additionally, The Weather Channel has strong potential for mobile content, where it has been a pioneer in working with various carriers and top news sites.

Summer reading tip: Anyone wanting a good read about the real challenges of creating a vertical channel should read Frank Batten’s account of starting The Weather Channel.