It will take a lot more technology than the Space Shuttle to control the worlds weather.

Making a tornado is not easy for nature to do. Everything has to come together, and even when all the ingredients are there, they usually do not form.

Here is what has to come together (taken from here http://www.knmi.nl/voorl/verken/english/tornado_doce.html);
· the strong low level convergence and intensification of (low-level) vorticity (i.e. low -level cyclonic circulation) within/of severe thunderstorms.
· and also:
· Considerable depth of convective instability
· High values of thetaw (18-23°C) in the lowest layers.
· Marked potential instability (thetaw falling 5°C or more up to 500 hPa)
Marked vertical wind shear with winds veering and increasing with height.

Stopping a tornado from forming would be easier than creating one. By cutting the solar energy with some sort of solar shade, the tornado could not form. A tornado needs the sun's energy to form.

One day man will posses the knowledge and technology to control the Earth’s, Mars and Venus’s weather, but we are centuries away from that.