Interesting weather study.
They study what happens under certain circumstances but it would be so much more informative if they also included the why part involved in the phenomenon.
For instance, what part of the world does the heat come from that causes the polar vortex to move and why does the sun heat that part more than other parts.
https://www.climate.gov/news-features/blogs/enso/el-ni%C3%B1o-and-stratospheric-polar-vortex