well, i've got a slightly different take on how this thing is functioning.
think epsilon simply isn't a 'true' tropical hurricane. not implying that it isn't really a hurricane, because it obviously is, but to the purists out there who think a hurricane isn't a hurricane unless it functions by barotropic processes over 80F waters, and not cooler waters... this is something else.
i believe that because it's later in the year and the tropospheric heights are generally lower than would be in the summer, that this thing can function with a much shallower warm core and keep the necessary differential 'heat-engine' in a more vertically compact manner. this kind of logic wouldn't hold up with wilma, which managed to intensify in vertical shear conditions somewhat similar (although it was moving a bit quicker and in a stronger baroclinic zone). but in this case, and also with delta somewhat, the hurricane's convective tops are low enough that fast winds above say 300 mb aren't hurting it a whole lot. it'd be really interesting to know what the omega values (sort of like the lift, if i understand correctly) are like near the top of and above the boundary layer. i'd suspect that the outflow levels with this thing is a lot lower than an august or september storm in the deep tropics. it's really too bad a recon can't be managed for this thing, because it defies the rules and could probably expand the understanding scientists have about how hurricanes really function.
anyhow, jeff masters has commented on how weird the storm's ability to function in conditions that usually kill a hurricane in 24-36 hrs for several days is.. and has mentioned that some grad out there ought to be collecting data for a thesis or dissertation. i haven't heard from him, but i'd bet clark is taking notes on this one, or at least some of the oddballs we've had this season... for his phase-analysis work.
a'ite, well, here's to epsilon finally realizing that it's december, and succumbing to shear.
fyi, chaos saying this thing was like a zombie isn't an inept description.
HF 1216z05december