Many thanks, reloading the .obj in blender did it! I simply had Blender recalculate the normals on the imported model and re-exported it, it now is rendered correctly rendered by Tacview.
I attached the .obj file for anyone who wants to use it. Instructions on how to add it in Tacview are available on the website: http://www.tacview.net/documentation/3dobjects/en/.
Feel free to use it at your liking Vyrtuoz, you may freely add it to Tacview if you deem it of high enough quality.
tornado.zip