Norman wrote:
Martin Rowley wrote:

"Martin Rowley" wrote ...
"comp.john" wrote in message
... On 2009-12-07, John Hall
wrote:
The GFS Ensemble 850mb temps for London are now looking decidedly
chilly:

http://91.121.93.17/pics/MT8_London_ens.png
What do the coloured P numbers mean down the left side of the chart?
... tags identifying the individual perturbation outcome depicted on the
composite plume. P=0 is the first perturbation, P=1 is the second and so
on. The colours match the individual (thin) lines on the chart. Useful if
you're trying to identify clustering of the members of the plume-set.
... I should have added that for each main time-step of the ensemble run, a
set of 'postage stamps' will be available. They're called that because they
look like a sheet of stamps you might see in a post office.

Usually (based on the EC output), for the main VT times, each 'postage stamp'
sheet will show the 'operational' run mslp pattern, the 'control' run mslp
pattern, and for each perturbation, the model's idea of what the mslp pattern
would be that produced that individual outcome.

So, the analyst would look as these data - and want, say to investigate why
P16 was markedly colder than the rest, and view the mslp (and perhaps other
diagnostics) that are attached to that particular outcome.

We don't (AFAIK) see these on the open 'web', so in a sense the coloured 'P'
lines/numbers aren't of high relevance.

Martin.


The GFES 'postage stamp' sheets are available at

http://www.netweather.tv/index.cgi?a...wer;type=panel

They are in 6-hourly time-steps out to T+384.


Norman

This one is really useful for comparing all the models:
http://www.netweather.tv/index.cgi?a...odelcomp;sess=

--
Keith (Southend)
http://www.southendweather.net
e-mail: kreh at southendweather dot net