I'm not sure this kind of thing is possible. One way to do it would be to create a daycycle that occasionally has a very small interval of bright light and sky, but I think you would have a VERY hard time lining that up with any events to trigger sounds for it.
Otherwise, you could just do it with events, and now that shaders take light radius into account, you could create an extremely large (but not extremely bright) white light to simulate thunder. The downside to that is that the sky wouldn't light up, because there aren't any events to change the environment.
TL;DR: Even if someone had the time, it doesn't appear easily possible at this point.