In article .com,
(Jim) wrote:



The US Federal Meterorlogical Handbook #3 is a good reference

http://www.ofcm.gov/fmh3/text/default.htm


Thanks for that link. Can't get the illustrations to show themselves.
Sometimes I curse Internet Explorer!

I have also found a New Zealand site with detailed 'how to' on Pibal. So
now I know what it means :-)

Brian.