On 09/07/17 13:18, Ron Button wrote:
Just watched that giggly woman on BBC news channel having showed the
radar picture for the UK which shows a large area of cloud covering much
of Eastern England followed by the usual warning to slap on high factor
sunscreen because of the strong sunshine
Having seen the heavy Cu build up to virtually 8/8 cover here in the
south-east since late morning ,what could possibly cause this overcast
to dissipate and therefore come into line with what is obviously an
incorrect forecast ?



I was told years ago that UV levels when Cu is around can be higher than
when there is no cloud. I think what happens there is that you get a lot
of reflected radiation.

Another point is that I assume the cloud was CuSc (I haven't really been
noticed as I've been watching the cricket) as you can't really have more
than 4/8 cover of Cu. It may look like more but, when assessing the
amount of Cu, you have to ignore the sides of the cloud and merely add
up the area of the bases.

--
Graham P Davis, Bracknell, Berks. [Retd meteorologist/programmer]
Web-site: http://www.scarlet-jade.com/
“Like sewage, smartphones, and Donald Trump, some things are just
inevitable.” [The Doctor]