On Wednesday, July 26, 2017 at 5:49:09 PM UTC+1, wrote:
On Thursday, July 20, 2017 at 2:56:57 PM UTC+1, Graham Easterling wrote:
On Thursday, July 20, 2017 at 2:54:39 PM UTC+1, Graham Easterling wrote:
SNIP
On Tuesday, July 18, 2017 at 7:11:57 PM UTC+1, Graham Easterling wrote:
Around 200mm (thanks Bernard) rain fell near Coverack in this afternoons major thunderstorm. Almost all the rain fell prior to this morning Weather Warning start, which was 17:00, by which time the sun was back out in Coverack. The most severe period was 14:00-16:00,


Graham
Penzance

The official figure for the Coverack storm, seems to be just over 100mm, but I've now seen 2 separate reports indicating 160mm & 170mm. A small patch of torrential rain & large hail barely moved for some time.

The 170mm is essentially based on a bucket - but in the absence of anything else. https://www.coverack.org.uk/pages/news.html

Culdrose received 1mm during the period.

Graham
Penzance

I should have included this:-

"Rainfall amount Mathematical challenge.
Tuesday 18th July 2017 in the afternoon
A three gallon builders’ bucket was used in the morning to carry wood chippings.
It was left empty in a space over two metres away from the nearest building.
On the evening of the same day the bucket contained water to a depth of 232mm.
The diameter of the top of the bucket was 310mm, with a lip to pour contents for
about one eighth of its circumference (120mm)
The volume of water contained in the bucket, measured the next day, was 13.014
litres. There was no perceptible change in level overnight.
This was measured by weighing the water in the bucket on bathroom scales 13.6Kg,
and subtracting the weight of the containing vessel, 586g.
I believe this gives a result of about 173mm of rainfall.
If the amount of rain added by the shape if the lip is removed, then I believe that
reduces the amount of rainfall to about 170mm."

The 160mm figure nearby was derived in a similar way.

Graham
Penzance
Graham,
Can you say where this came from as it appears to be the original source for a discussion I have seen elsewhere?
Thanks,
David

I've resurrected this old thread, as the 'bucket' measurements now have the support of the EA.

After suggesting a rainfall of 105mm just after the event, they now think the rainfall was near 200mm (more than the bucket!). In fact on the Local news tonight it was suggested the rainfall may have been greater than the last Boscastle event.


Graham
Penzance