The Intractable Studies Institute has published a communication for How to Disrupt a Standard Tornado at http://intractablestudiesinstitute.org/communications/Tornados.pdf. In a nutshell, this solution works by defeating the principle of normal air-pressure in surrounding area dropping to lower air pressure as it approaches and enters the funnel. The specific technique used to prevent a drop in air pressure is air bags of constant diameter. Please see the pdf diagram.
Patrick Rael, Director of the Intractable Studies Institute