Graham Easterling wrote:
Still sunny here too but becoming very hazy.

Interesting to note that despite yesterday's (and the last month's) blue
sky, the sun index has struggled to make it much above 4 down here in the
South West. And yet, today (despite the milkiness/haze of the sky) the sun
index has gone above 6.

What was it in the previous air mass that filtered out much of the UV, even
when the sky was deep blue.


Nick

Just checked Camborne (where it's very hazy indeed, bright rather than
sunny a lot of the time) and it's 6.

I think it's partly the change of air mass, but also I've noticed
(mainly from practical experience!) that thin layers of low cloud, or
patchy sea mist which let the sun through, seem to enhance the UV
intensity. (Can anyone confirm this?).

Graham
Penzance




So far today mainly cloudy but index has reached 5.8,(although fallen
back to 3.0 now) yet in the three days of wall to wall sunshine(1st-3rd
of May) we did not achieve 5.0
An explanation would be very interesting.

Alan
Wincanton
www.wincantonweather.org.uk