A huge advance in synoptic meteorology came with the emergence of the polar front theory of midlatitude cyclones at the end of the First World War. Since then, the large amount of research into midlatitude weather systems has led to many significant discoveries, particularly about northern hemisphere systems, and the development of new conceptual models.

Many of the synoptic-scale cyclones which develop in and/or pass through the Southwest Pacific have structures which do not completely conform to the polar front model. Some exhibit a frontal T-bone and bent-back warm front in the manner of occluded marine cyclones studied in the Experiment on Rapidly Intensifying Cyclones over the Atlantic (ERICA). Others are not easily classified. This paper will present case studies of recent "non-classical" extratropical cyclones over the Southwest Pacific and discuss appropriate ways of depicting the system-relative flows within them.