The feature promises to show you which of your Facebook friends is in the path of the perfect storm, presumably so you can text, "OMG r u ok? hope u dont die lol." It sounds like a nice idea...but it's not.
Using this feature allows the Weather Channel to access your Facebook information. It's the sleaziest type of self-promotion, using people's fears about a possible disaster to further the brand. What's more, once you've used this feature, the Weather Channel can use your picture to promote its own page on your friends' walls.