On 14/09/2016 09:13, Graham Easterling wrote:
After yesterday afternoon's storm (flooding near Truro) and yesterday's early evening storm (15mm in Penzance, 30mm reported at Redruth) came this mornings storm (around 03:00-04:00), with loads more lightning.

It's no unusual to get 3 showers with a flash of lightning within 24 hours in winter, but to have 3 separate (as opposed to immediate following cells) impressive storms in such a short space of time is.

Yesterday, when it was dry it was pretty dark, misty, gloomy, and very cool in the afternoon.

24 hours ending 09:00
Max temp 18.7C (at 09:00 today)
Min Temp 16.6C (mid afternoon yesterday.

Total rainfall in Penzance 25.6mm, of which approx 15mm fell in 40mins commencing 19:00 yesterday.

Plenty of pictures on the web of people enjoying the 'heatwave' in Cornwall yesterday. (It certainly wasn't just grim up north & hot in the south as many posts suggest.)

Exciting though.

The intensity of the rain has caused some sewer overflows, including at Gwithian, where SW Water refuse to except the regular problems.

Plenty of problems still http://www.sas.org.uk/map/ (zoom in to Cornwall)

Due to intensity of the rainfall, not wise to swim in the sea near a river this morning.

Graham
Penzance


Are you aware of any public airing/discussion sites for general sewage
problems in the UK?
Near me I'm aware of a major problem with the local sewage works. The
houses near it are below the sea level of even normal high spring
tides, but the main problem is with the works. Replaced storm-drain
outlet flapvalves have helped the marine flooding they used to get. It
seems that in high rainfall/cloudburst events over land , the sewage
works is supposed to handle road run-off of rain , plus house run-off,
but cant. It looks as though to protect its own plant , the motors to
the very large Archimedian Screw lift pumps are deliberately
automatically tripped out. Then that whole area including the periphery
of the sewage-plant floods , from overflowing foul water sewer system,
that then fills the storm-drain system, which at elevated high tides
then can cause more extended problems.