Gedday again,

Since doing this discussion group, I have finally learned why I became a Meteorologist all those years ago: Its because I am long-winded.

Anyway.... The other interesting thing going on is the cloud-band across eastern Australia that developed behind Sunday’s cool-change/summer-time front, that was described so well by Kevin Parkyn a few days ago.

The simple-man’s (i.e mine) dynamical explanation for this is, of course, upslide associated with upward motion on the eastern side of a 500hPa trough.

There are a couple of interesting things about it:

**    The development or movement southwards of the moisture actually came from the north to north-east (rather than the north-west) and occurred over the preceding several days.  This can be seen in the sequence of thetae charts that I have put on my web-page: 18th 1100,   19 1100,   20 1100.

**    There was an absolutely incredible development in the 350 degree Isentropic Potential Vorticity, with a strong anticylonic slot developing and extending southwards across eastern Australia and into the Tasman.  Admittedly I have been looking at IPV charts for only a short time, but I haven’t seen anything else like this.  Is this a common structure for upslide/NW-cloudband type situations?  I don’t think Roger DesLandes is on this discussion list yet; but I am cc-ing this email to him, in the hope that he may know something about PV in mid-latitude upslide.
   IPV charts: 19th 1100,   20 1100,   21 1100
 Related to this is the interesting jet-stream structure whereby we have the STJ oriented Northwest-southeast in two parallel bands from the Bight southwards, and across the Coral-Sea-Tasman see jetstream analysis.
 

Any thoughts or ideas on this structure??

JMcB