Preliminary analysis shows that for increasing magnitudes of deep-layer vertical wind shear, RI onset is increasingly delayed. In addition, a critical shear threshold appears to exist in which the TC will not intensify once it is exceeded. Although the timing of RI varies by as much as 48-h, a decrease in wind shear is observed across the intensifying composite groups approximately 1224 h prior to RI. This decrease in wind shear is accompanied by a reduction in the magnitude of the tilt of the vortex, as the precession and subsequent alignment process begins approximately 2448 h prior to RI. However, it is important to note that variations amongst additional environmental variables are also present, particularly in the members that do not develop. These storms track further west than the developing members into an environment of not only increased vertical wind shear, but also somewhat less favorable sea surface temperatures. However, the moisture content in the non-developing members is more conducive for development. Using both the WRF-EnKF ensemble simulations and the HS3 sounding observations, the pathways to intensification (or lack thereof) are currently being examined in greater detail to assess the interplay of the various environmental variables on the structural evolution of the TC vortex.