Basically the same idea as this....

however instead of it being on your Desktop page, it sits on your Facebook home page (possibly on the right where the adverts normally are) giving live local conditions.
Once the weatherzone home page app was seen on peoples home pages it would spread like wild fire and with the widget having the link to the Weatherzone site it would have a heck of a lot more people accessing the site which of course would benifit Weatherzones and there sponsors who place adverts on the site.