Storm Movie?

it's some movie involving a bunch of supercells all joining together and the storm is practically feeding off itself. two main characters are a man and his son. in the end the son breaks up the supercells by running a copper wire from some HUGE propane tanks up into the clouds by way of a model rocket, lightning runs down the copper wire and the propane tanks explode and the storm breaks apart. i think mid to late 90s.