However, there seem to be several methods of tornadoes forming.
This is a wide one forming as a cloud vortex. I have seen clouds starting to spiral, and when I see those, I break them up.
This is a narrow one forming as a tail cloud reaching downward.
Another theory says that tornadoes form as horizontal tubes and then tilt to vertical. This looks like that.
It may be that we need different types of prediction to spot the different methods of formation, beyond the general "severe storm may spawn tornadoes." Certainly we need more study, as tornadoes are not well understood yet.