Dark Sky's creators Adam Grossman and Jason LaPorte on how they developed their breakthrough meteorological technology. Adam Grossman, Jack Turner, and Jason LaPorte had an idea for a simple weather app, with one major twist. Instead of predicting weather by the day or week, their app would predict rainfall minute by minute-one hour into the future. Since launching Dark Sky, their Troy, New York-based company, in 2012, the co-founders have plenty of satisfied (and dry) customers. The $4 app has been downloaded more than 100,000 times. Here's how it all started. Getting Drenched on I-90 Grossman: I was driving to Cleveland with my girlfriend to visit my family. We were on I-90 and stopped at a rest area to get some gas and food. When we were inside, it started pouring--just one of those summer thunderstorms that sneak up on you and start pouring buckets. We didn't want to go back to the car, because we would have gotten drenched. The question was, "When is this rain going to let up?…