Just after the Southern Tablelands cell intensified it showed interesting structure. The timelapse I guess confirms that too. Strong outflow pushes out in the timelapse. At the time of this photograph and just prior though, strong inflow raced in from the northeast!
Was it an outflow boundary from the the supercell now in Nowra? Or was it rapidly rising updraft not sure - https://youtu.be/qTcU5ckJ_fc Timelapse (yes I know it is heavily processed but I had to as the contrast at the time was not the best but the structure was evident)