Paul.
As far as I understand highs are formed where air decends. This being from
air that was warmed and accended elsewhere, ie. the equatotrial regions
where low pressure is formed by warmed rising air.
Hope this helps but I'm sure its far from the whole story.

Regards. Len.
"Paul Hyett" wrote in message
...
I understand how lows form (more or less), but what factors govern the
generation & intensity of high pressure areas?
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Paul Hyett, Cheltenham