Keith -- conditional slantwise instability isn't really found within tropical cyclones. It is true that the system is neutrally stable to moist slantwise convection; however, that does not imply conditional symmetric instability is present within the storms. Instead, CSI is found north of warm fronts in relatively stable environments (not a tropical cyclone!) during the wintertime.

It is possible, however, to have conditional symmetric instability within the convective structures found north of extratropically transitioning tropical cyclones, way up there in the North Atlantic. Usually that is dominated by other, upright instabilities, but CSI may play a role. A similar slantwise instability was found to play a role, for instance, with Floyd at landfall, a system that was interacting pretty heavily with the midlatitudes and on its way to transition.

I'll be presenting a poster on this very topic in about 2 weeks at a conference in Washington D.C. -- if anyone is around there and wants to pay the $250 or so registration fee, feel free to stop by!

I was thinking more along the lines of topographically-induced convergence and things like that, not so much instability or convective-types. My mistake...