On Monday, 10 July 2017 15:34:24 UTC+1, Graham P Davis wrote:
On 09/07/17 19:44, Norman Lynagh wrote:
Graham P Davis wrote:

On 09/07/17 13:18, Ron Button wrote:
The old scientific law of "what
goes up must come down" was used to explain how at least half the sky
would be be cloud-free due to the descending air
The descending air doesn't necessarily occur in the vicinity of the cloud formed by the ascent of the air, though. I used this argument when I was being trained, but was told to carry on using the rule of thumb (I didn't!). I can see the logic behind what you are saying, but I would argue that it only applies to cumulus of limited vertical and horizontal extent - which is probably more often than not. I can't see any problem with reporting 8/8 Cu, but I would expect to only do it when the air was unstable to some depth, and I would expect to be reporting precipitation at the same time.

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