A strong upper front is nearing Tasmania and features prominently in the 27-11-2013-18z, WeatherTheatre Analysis, snapshot. The front is made apparent by a deeply folded tropopause (upper surface), seen in the background of the Southeasterly Perspective below. As a result, rapid cyclogensis is occurring with a surface low quickly deepening. Most forecast models show the low situated east of Tasmania by Thursday night.
A small upper trough over Western Australia, marked by a tropopause vorticity-tube extending down from the surrounding tropopause surface above, can be seen in the right of the snapshot.
Thin filaments of cyclonic-vorticity, visible in the foreground, are due to a Ex-Tropical Cyclone Alessia which is located over the Gulf Country.