This split was caused by the much-anticipated Second Warming that I have been posting about for days on end. This second warming is the second 'C' in my new 'Three C's' List, which consists of the following:
The Corrosion refers to the weakening of the polar vortex to a point of a state that it has not collapsed, but has sustained damage to the point that a split is possible. The Crack refers to the split in the polar vortex, when a stratospheric warming forces the vortex to crack into several vortices. And finally, the Collapse indicates the polar vortex can no longer control the Arctic, and its vortices are forced south into lower latitudes. I believe we are well on our way to the last stage of Collapse, shown by the chart below:
THERE IS NO POLAR VORTEX. It's GONE. It has actually gone beyond Collapse into a whole new level of disintegration.
We just want this disintegration to propagate down to the lower stratosphere, like the level 475 K shown below (roughly 105 millibars, the very bottom of the stratosphere):