"Martin Rowley" wrote in message
...

"Jeremy Handscomb" wrote in message
...

PS Alternatively you could find a map that shows the lines of
thickness!
They are around somewhere but I'm afraid I don't know where to find
them.



http://www.westwind.ch/?page=gfsg

there are others: but don't get 'hung-up' on thickness (500-1000hPa) ..
it's useful, but for tracing low-level airmasses, use ThetaE or similar.

Martin.

ThetaW data is now available here up to T+72,
http://meteocentre.com/models/modelsukmet_eur_e.html

Jon.