At this rate, my general feeling is that Local Now is obviously the successor to the Weatherscan service but for at least the near future, they'll operate concurrently. Even up to last summer, TWC was still signing agreements with cable providers and co-ops that included a Weatherscan clause. The channel is pretty cheap, even with maintenance of 13 year old computers. The way I see it is pretty much in line with what someone around here said a few years ago. Weatherscan will continue, as is, no major changes until all the machines stop running or so few are in operation that TWC can't justify the cost anymore. Even with the migration to online weather information and Local Now, Weatherscan remains a very popular service when available to subscribers. I mean here, the channel gets numbers on par with ESPN, that also makes it a very enticing option for businesses who want to advertise.
So yes, the channel has to go off-air eventually, just not for a few more years at the least.