A small disturbance in the sub-tropical jetstream over Western Australia features prominently in this morning’s WeatherTheatre Analysis, at 25-11-2013-18z. It can be seen in the adjacent WeatherTheatre snapshot as a tropopause front with a trailing vorticity tube to the mid-troposphere. The disturbance is assisting a surface low over the Gascoyne/Pilbara region.
A mid-latitude upper front in its mature phase is apparent in a tropopause fold seen south of Western Australia in the background of the south-westerly perspective snapshot. The easterly perspective snapshot shows it on the far right side.
In the background of the easterly perspective snapshot, a persistent upper disturbance and associated tropopause folding situated over the Tasman Sea is visible. This is better seen in the south-easterly snapshot which shows a tiered appearance to the folding, due to the polar jetstream merging with the subtropical jetstream over the eastern Tasman.
The top-down perspective below provides a good indication of the geographic layout and extent of the features described. The two disturbances in the west are visible on the left with darker shadings indicating the steepness of the tropopause surface in the frontal regions.