Disclaimer: It's probably not a good idea to leave your window rolled down during a thunderstorm. Lightning can make it's way in to the car. However, wet windows make it hard to film anything and lightning was more likely to hit the car's antenna and I did roll up when it was striking directly over top of me. If you don't understand and respect the risks involved or feel uneasy about being struck by lightning, don't do it! You run just as much of a risk of being struck out in the open as you do with your window rolled down.
Here is the radar image of this storm.