The numerical model used is CM1 by G. Bryan (see http://www.mmm.ucar.edu/people/bryan/cm1). The 3D-visualization was created with VAPOR (see http://www.vapor.ucar.edu).
One time step relates to two minutes "real time". The filled contours at the surface show potential temperature perturbations with a corresponding colorbar. Arrows illustrate wind speed and direction.
3D-rendering of cloud water and ice contents in grey,
of rain water content in purple,
of vertical velocities greater 25 ms⁻¹ in yellow,
less than 10 ms⁻¹ in green,
of vertical vorticity greater 0.035 s⁻¹ in orange,
less than -0.035 s⁻¹ in dark blue,
of negative pressure perturbations less than - 10 hPa in bright blue.
Background rotation is set to 3*10⁻⁴ s⁻¹, there is no surface friction implemented in the model.
Tornadogenesis is taking place during time steps 70 and 78 and can be observed by positive vertical vorticity and an intense negative pressure perturbation.
For more information - my current professional email: sebastian.mueller ät mpimet.mpg.de