Does Comcast have any alternate weather feeds, like from a local news station or something?
Not here... anymore. Boston's NBC station carried NBC Weather Plus, which had its own channel on Comcast digital cable, very near Weatherscan, actually. However, since Weather Plus ended, no local station or cable network has had its own dedicated weather network.
Orlando television has two local channels with dedicated weather subchannels, but, of course, the weather in Orlando is oftentimes much worse than in Boston.