As I speak we have a nice long rainband approcahing Melbourne.  This is
associated with one of those short-wave features I have been talking about
whereby an upper-level trough of about 100 km by 100 km scale breaks away
from the higher-latitude long-wave-trough, travels up towards melbourne,
interacts with things over the continent and brings about cool-changes,
or in this case rainfall. I was talking about this a week or more ago (as
in the email from Lance Bosart).

I have a few more questions:
a) To me it is interesting that the models can pick up the large scale
analyses and simulate the existence of a very small scale feature 4 days
ahead, and get it in the right place and time.  This seems
counter-intuitive. the extension of it happening is to run a mesoscale
model and say that in 2 days time, a tornado or downburst will hit number
3 Brougham St, but will miss No. 5 Brougham St.

        What is there in the analysed fields of 4 days ago that ends up
with a mesoscale feature in the right place and time?  Is there a small
scale feature in the initial analyses that is preserved:  Or is there
something in the initial large scale configuration that evolves (through
circumpolar vortex surf-zone breaking, or through downstream energy
dispersion, or through etc.. etc.. ) to a short wave feature in this
particular spot?

        How does this relate to energy cascades in the atmosphere?  i.e
what theory gives the large scale fields evolving "downscale" to these
shortwave feature?  I think I'll develop my thoughts on this a litle
further, then send off some emails to some dynamicists who may understand
these things: e.g Tim Palmer and/or Jorgen Frederiksen.
        One speculation I have is that it is related to singular vectors
and to their growth in space and time:  I can explain these in a later
email; but both Kamal Puri and Mike Naughton are on this mailing list and
understand them better than I do:  so perhaps one of these two gents will
volunteer a paragraph or two understandable explanation.

Trish is ringing and wants to go home... so, I'll continue tomorrow.  One
more quick one:
Do these litttle upper level lows cutoff and drift northward at other
longitudes, or is the whole process somehow forced by the existence of
the heated continent to the north?  Does anyone know?  How do we see this
on the maps and diagnostics we have currently available?

There's the phone again... I'll talk more about this later

John McB