Why does poured honey move periodically when reaching the surface it's poured upon?

Here’s the picture, known to most of us:

When honey is poured out of a container, as in the picture (look here for the flow in motion), we see a kind of periodic flow of the honey when it comes to a stop at the surface, it’s being poured upon. One can see a nice visualization of this effect here too. I thought an explanation was given there but it wasn’t.
Intuitively, I can feel why it happens. But then again, it could have been the case that the honey keeps on flowing to just one side instead of making a circular or to-fro motion.

So, what’s the physics involved? Can we apply the Navier-Stokes equations or can we make use of the Stokes flow, which seems more appropriate in this case? How to apply it? Of course, we can always search for sanctuary in a TOE, but I think in this case…hmmm…