At 11:55 05 September 2009, Spam wrote:

On a 2-4 knot day, where the growth of the cloud is hard to see while
your changing positions going 60-75 knots, is there any trick to
really studying the cloud vertical growth? Cumulus boomers are easy
to spot, but an average soaring day, it is hard for me to tell if the
cloud grew upwards, or if it just appears different since I'm flying
along towards it.


I try to watch the next likely cu for signs of growth while I am circling
under the previous one, when you get one view every 30 second turn from
the same distance. Also go for the cumulus clouds with the lowest bases,
as they decay from the bottom upwards (a tip given to me by an ex World
Champion).

Derek Copeland