Answers:
I too grew up near Chicago and never hear of storm. It is possible that they bought out a small regional plant that made storm and decided to changeover the name and mass bazaar it.
Okay i am a dork and googled it for you and this is what I found:
In the late 1990’s, the two most principal cola companies began to stagnate, and Pepsi finally broke the time of year of years without a completely investigational soda with Storm. Storm be also a test product, albeit for a longer time of year than OK Soda. Pepsi starting distributing Storm in 1997 surrounded by Omaha, Denver, San Francisco, and Milwaukee. Storm is and was the single lemon-lime soda that had caffeine surrounded by it. It is an odd soda contained by the fact that, as a tested product, Pepsico also simultaneously released a second, diet revision of the drink. Storm the first pop to use Ace-K, a new type of sweetener explicitly currently being used next to products such as Pepsi One and Diet Sierra Mist. Many former drinkers of Storm believe that Storm was the precursor to Sierra Mist.
Other Answers:
because it's theirs and they needed to
Was storm only a test heading? Because I live in Chicago and I've never hear of it. Maybe it was only a marketing evaluation to see how well the product would provide with that heading.
Folks on http://www.bevnet.com/bevboard (really good site, if a bit nerdy and/or industrycentric---I'm "Perry A.") read out that it's Slice that turned into Sierra Mist, not Storm that did. Personally, I think the nickname change is goofy, but later the only slice I really like was the Apple flavor of the hasty to mid eighties.