Tornadoes are fascinating, still there's so much we don't know even though much has been learned in the last 20 years.
The question that I've been pondering arises from so many images of the cyclones that seem to have a point of convergence. It's as though the funnel nearly disappears to a thread, perhaps an imaginable "stream filament" (Bernouli, Milne-Thomson), then diverges to the business end along the ground.
There is a toroid flow of air surrounding part of the funnel above this "convergence zone" and usually there is a lightning storm that accompanies the cyclone, often preceded by hail. All that suggests an electromagnetic field surrounding the cyclone.
One question I've had for a while is, with all that known, is it possible that a needed condition is a stray magnetic line of force, similar to a seed of impurity is needed for bubble nucleation. The question that followed that, for me anyway, about 4 years back, is whether, if the cyclone was to converge in the upper atmosphere, magnetic connection or not, wouldn't that tend to drop the temperature to sub-zero around that region? If that happened, wouldn't it tend to also freeze, if not super-freeze, the moisture as the funnel descends?
It was odd because about a year ago I checked out the video "The Day After Tomorrow" and saw that as something spawned from another mind some years prior to my notion about the same thing. Not that it's the subject; I think it's also fascinating how more than one mind can be thinking in the same channel void of either knowing the other even exists