While we could go the direction of mispronounced names, with great pleasure (or disgust, as I listen to Cleveland-based newscasters on "FM News Talk 104.7" here), I'd like to stick to the original point. The Weather Channel is just one more cable channel that decided it needed to expand its purpose.
To use another example, A&E is hardly "Arts and Entertainment" anymore, unless your idea of "entertainment" is reading the police blotter. Food Network still finds food-based programming in its reality shows, but I suspect a desire for original purpose is why also you now have Cooking Channel, which I presume is a spin-off.
On A&E there was a promise of a more highbrow approach, but A&E is about as highbrow now as WQED-13 in Pittsburgh or any other "public" station when they bring out old BeeGees and doo-wop concerts and helicopter flights over Italy in a bid to get donors who otherwise might see "Frontline" or "Washington Week in Review" and flee. But here even I digress.
TWC's original purpose can be seen on its Weatherscan channel. However, that hardly will keep a viewer beyond a check of the forecast and the current conditions. Ergo, this desire for programming such as "Weatherproof" (which is useful) and "Cantore Stories" and "It Could Happen Tomorrow" (which makes for great fiction and I guess is supposed to make a point about preparedness, ala "Weatherproof").