In uk.sci.weather on Mon, 15 Sep 2003 at 07:31:47, martin rowley wrote :

... I think you are looking at the 552dam contour (used to track major
long-wave pattern changes) - see the link below for more on output from
various centres with examples, explanation etc.

http://homepage.ntlworld.com/booty.w...dels/sites.htm

Thanks for this - very useful.

Just one question : If hPa is the same as millibars (as seems to be the
case), why have two names for it? It's like Celcius & Centigrade.
--
Paul Hyett, Cheltenham, England