In article , Nick
Whitelegg writes
Wonder if anyone from uk.sci.weather could shed some light on this?
(Saturday August 23 last year, Mynydd Du also known as the Black
Mountain, South Wales). Meant to mention it last year but never got
round to it....

Be careful not to confuse the Black Mountains (Eastern area) with Black
Mountain in the Western fans.
--
Bill Grey
http://www.billboy.co.uk