Nov 262013
 
WeatherTheatre 25-11-2013-18z Snapshot

WeatherTheatre 25-11-2013-18z snapshot, south-westerly perspective.  A disturbance in sub-tropical jet over Western Australia is visible in the upper right foreground (upper surface) and a mid-latitude disturbance behind it.  Red shadings correlate with the strong winds (upper surface and vectors) and warmest temperatures (lower surface).  Conversely, blue shadings correlate with the weakest winds (upper surface and vectors) and coldest temperatures (lower surface).

WeatherTheatre 25-11-2013-18z Snapshot
WeatherTheatre 25-11-2013-18z snapshot, easterly perspective. The tropopause front over Western Australia is seen in the mid-foreground (upper surface), while the mid-latitude front is seen on the far right. A disturbance persisting over the Tasman Sea is visible in the background.  Red shadings correlate with the strongest winds (upper surface and vectors) and warmest temperatures (lower surface).  Conversely, blue shadings correlate with the weakest winds (upper surface and vectors) and cold temperatures (lower surface).

WeatherTheatre 25-11-2013-18z Snapshot
WeatherTheatre 25-11-2013-18z snapshot, south-easterly perspective. The disturbance over the Tasman Sea features prominently. Tiered tropopause (upper surface) folding is occurring as the polar jet merges with the sub-tropical jet, creating a stepped appearance to the tropopause.  Red shadings correlate with the strongest winds (upper surface and vectors) and warmest temperatures (lower surface).  Conversely, blue shadings correlate with the weakest winds (upper surface) and coldest temperatures (lower surface).

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.

 

 

WeatherTheatre 25-11-2013-18z Snapshot

WeatherTheatre 25-11-2013-18z snapshot, top-down perspective.  The merging of the polar and sub-tropical jets is evident over the eastern Tasman in the far right. The disturbance in the sub-tropical jet over Western Australia is seen on the mid-left side and the disturbance south of Western Australia on the lower left.  Red shadings correlate with the strongest winds (upper surface and vectors) and warmest temperatures.  Conversely, blue shadings correlate with the weakest winds (upper surface and vectors) and coldest temperatures (lower surface).

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