Fifteen north Atlantic tropical cyclones (1998-2002; AVN operational analyses) that underwent extratropical transition have been composited in storm-relative coordinates to determine the common aspects of the synoptic environment associated with ET. In this talk, four specific points in the ET lifecycle will be examined: 1) TB-48hr, 2) TB, 3) TE, and 4) TE+24hr. Both the composited mean conditions, and the individual storm departures from that 15-cyclone mean are considered. The factors influencing whether a tropical cyclone intensifies after transition completes or dissipates are reviewed. Further preliminary indications of the impacts of a synthetic (bogus) vortex on post-transition storm structure evolution within the operational analyses are gained by examining differences in the mean conditions at TE+24hr between the AVN and NOGAPS analyses.