Fascinating.
As I saw the animation, the first thing I thought of is that it looked like they were dancing.
In my youth I spent many a pleasant summer week at my uncle’s beach house on LBI in Beach Haven. : (
I have seen this effect with vortices in liquids: water, oil, and after I viewed the wiki page http://en.wikipedia.org/wiki/Fujiwhara_effect I realized that I had seen this in the Pacific. However, I have traditionally paid very little attention to Pacific cyclones, and I have NEVER seen this effect in the Atlantic basin, so it never occurred to me. I kept relying on some type of energy transfer mechanism in my thoughts of the reason for this track, instead of a more physical influence mechanism.
This season will definitely help these programming teams tune some parameters of their models in a way that nothing else can. It seems possible that they have close to sufficient code built in to them. I consider that quite commendable.
Not to divert the thread (which is probably impossible) but this also illustrates how very small disagreements of models with reality can drastically affect model predictions, and only after comparison with reality can models be properly programmed. It motivates objections regarding how we are decades away from completing the process of program, tune, observe, tune, observe, tune... necessary for the global warming GCMs, since accurate prediction of climate decades or centuries out relies on many cycles of pertinent tuning done after a decade or more of observation.