Most people here complain about graphics but I really like this very very unique gameplay idea. Keep it up. It really reminds me on Twister (a great film) and you should really waste a lot of performance on weather, no doubt.

The sound is very immersive now, maybe you should add as well lightflashes when a thunder hits the bottom, as well as a graphical representation of it. You should invest a heavy amount of time in rain and air convolution as well as all indicator signs that appear when a tornado is in the creation process.

I don't know if this is a sandbox game, but if you add a story or such (always good!) you should maybe show how people are fleeing or so. Watch the film Twister, it has pretty much material for such a game. I like it, keep it up!