Storms will be very tough as there is a lot of room for error. Electrical storms are often best shot in bulb mode, but can look very dramatic if you get them right. You need to be at an elevated position ideally (obviously ensuring you are also in a safe place. Do some research online to find the best set up. Is there anyone you know that you could borrow a DSLR from for this? As this would definitely be best done with a DSLR with some fully manual settings.
My personal advice is that you should stick to something simple so that you can work on exposure and composition. Find something interesting that has some leading lines leading to it. As I suggested in my PM, get hold of some photography books and try out some of the suggestions, and then post the best of them. Storm chasing is tough, very tough. Weather can be difficult also has sometimes you will think there is more contrast than there actually is. Find the most important building or the prettiest building and see if you can take an interesting photo of it using the rule of thirds and/or leading lines while having it well exposed. Use your better camera and see if you can find some manual settings so that you can actually have some say over the exposure. Unfortunately with your cameras you will have very limited say over depth of field because of the size of the sensor.
Keep it simple.