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Mike Tullett[_2_] · June 8th 08, 06:30 PM posted to uk.sci.weather

On Sun, 8 Jun 2008 19:11:42 +0100, wrote in
m

Hi All,

I'm a long time lurker who is just interested in the weather, but possibly
more so than your 'average Joe' which is why I enjoy reading all the
interesting stuff from the experts on here. I like to think I've developed a
better understanding of forecasting as a result of lurking here but there's
one thing that puzzles me and would really appreciate some guidance from the
contributors to this group.

One of the sites I regularly look at gives an 3 hour forecast window
including a UV index and this always peaks between 16.00 and 19.00 when, for
example, today and tomorrow (Sunday and Monday) it shows the UV level as 8
during these hours but only 6 between 13.00 and 15.59. I can't fathom out
why this should be - surely the UV index would peak when the sun is
strongest which, in summer time in the UK would be around lunchtime,
wouldn't it? Please bear in mind I'm a complete novice and have no detailed
understanding of weather systems and suchlike but info I've read on this
group has helped me understand a good deal over the last couple of years;
but I just can't understand why the UV level isn't strongest when you'd
expect the sunshine (when we get it) to be strongest.

Mike - you are quite right to question the times of 16.00 to 19.00. Solar
radiation, of any kind, will peak an hour or so either side of local noon.
Where I am now local noon is at 13.30 BST, so peak radiation will be
between 12.00 and 15.00
--
Mike Tullett - Coleraine 55.13°N 6.69°W posted 08/06/2008 18:30:06 GMT