You might find this interesting, if a little out-of-date.

http://maps.nls.uk/geo/explore/#zoom...ers=10rain&b=1

You can switch between the old rainfall map & the modern one by using
the 'change transparency of overlay' slider.

I finally know why Capil Curig is so wet!


--

Paul Hyett, Cheltenham

On Sunday, 4 September 2016 10:53:47 UTC+1, vidcapper wrote:
You might find this interesting, if a little out-of-date.

http://maps.nls.uk/geo/explore/#zoom...ers=10rain&b=1

You can switch between the old rainfall map & the modern one by using
the 'change transparency of overlay' slider.

I finally know why Capil Curig is so wet!


--

Paul Hyett, Cheltenham

Paul

I knew about this site, but had never noticed the 1881-1915 rainfall overlay.

Of course this begs the question if we have rainfall data to produce such a detailed map as this why do the Met Office only have a gridded data series that extends back to 1910?

Bruce.

On Sunday, September 4, 2016 at 11:19:53 AM UTC+1, xmetman wrote:
On Sunday, 4 September 2016 10:53:47 UTC+1, vidcapper wrote:
You might find this interesting, if a little out-of-date.

http://maps.nls.uk/geo/explore/#zoom...ers=10rain&b=1

You can switch between the old rainfall map & the modern one by using
the 'change transparency of overlay' slider.

I finally know why Capil Curig is so wet!


--

Paul Hyett, Cheltenham

Paul

I knew about this site, but had never noticed the 1881-1915 rainfall overlay.

Of course this begs the question if we have rainfall data to produce such a detailed map as this why do the Met Office only have a gridded data series that extends back to 1910?

Bruce.

A detailed map doesn't necessarily equate to accuracy. The MetO produce detailed actual and anomaly maps each month, showing rainfall in great detail over west Cornwall for instance. But where are the actual rainfall reports from? just Camborne & Culdrose. This can lead to some highly inaccurate maps, especially in summer. It was the extreme inaccuracy of these maps a few years back, that led me to realising Scilly was double recording rainfall. It still took them nearly 6 months from the time I reported it to correct it. The only reply I ever got was an unofficial private one, giving the reasons for the problem, in some detail - it was both interesting and disturbing (total lack of any reasonableness checks). I never got an official response.

It meant that the 'actual' figure for the Penzance area, presumably computed in some way from the Camborne & Scilly figures and a relief map, was 30% or so high for several months.

Graham
Penzance

On 04/09/2016 12:02, Graham Easterling wrote:

A detailed map doesn't necessarily equate to accuracy. The MetO
produce detailed actual and anomaly maps each month, showing rainfall
in great detail over west Cornwall for instance. But where are the
actual rainfall reports from? just Camborne & Culdrose. This can lead
to some highly inaccurate maps, especially in summer. It was the
extreme inaccuracy of these maps a few years back, that led me to
realising Scilly was double recording rainfall.

But Scilly does have their own weather station IIRC?

Hard to believe they never thought to cross-check!



--

Paul Hyett, Cheltenham

On Sunday, September 4, 2016 at 12:32:10 PM UTC+1, vidcapper wrote:
On 04/09/2016 12:02, Graham Easterling wrote:

A detailed map doesn't necessarily equate to accuracy. The MetO
produce detailed actual and anomaly maps each month, showing rainfall
in great detail over west Cornwall for instance. But where are the
actual rainfall reports from? just Camborne & Culdrose. This can lead
to some highly inaccurate maps, especially in summer. It was the
extreme inaccuracy of these maps a few years back, that led me to
realising Scilly was double recording rainfall.

But Scilly does have their own weather station IIRC?

Hard to believe they never thought to cross-check!



--

Paul Hyett, Cheltenham

The MetO station is the only one on St. Mary's that I know of. It was double recording rainfall for 10 months, from 1st Nov 2008 to 16th Sept 2009 even though I reported the problem after 4 months, it was so obvious.

There's also the AWS on St Martin's.

Graham
Penzance

On Sunday, 4 September 2016 12:02:41 UTC+1, Graham Easterling wrote:
On Sunday, September 4, 2016 at 11:19:53 AM UTC+1, xmetman wrote:
On Sunday, 4 September 2016 10:53:47 UTC+1, vidcapper wrote:
You might find this interesting, if a little out-of-date.

http://maps.nls.uk/geo/explore/#zoom...ers=10rain&b=1

You can switch between the old rainfall map & the modern one by using
the 'change transparency of overlay' slider.

I finally know why Capil Curig is so wet!


--

Paul Hyett, Cheltenham

Paul

I knew about this site, but had never noticed the 1881-1915 rainfall overlay.

Of course this begs the question if we have rainfall data to produce such a detailed map as this why do the Met Office only have a gridded data series that extends back to 1910?

Bruce.

A detailed map doesn't necessarily equate to accuracy. The MetO produce detailed actual and anomaly maps each month, showing rainfall in great detail over west Cornwall for instance. But where are the actual rainfall reports from? just Camborne & Culdrose. This can lead to some highly inaccurate maps, especially in summer. It was the extreme inaccuracy of these maps a few years back, that led me to realising Scilly was double recording rainfall.. It still took them nearly 6 months from the time I reported it to correct it. The only reply I ever got was an unofficial private one, giving the reasons for the problem, in some detail - it was both interesting and disturbing (total lack of any reasonableness checks). I never got an official response.

It meant that the 'actual' figure for the Penzance area, presumably computed in some way from the Camborne & Scilly figures and a relief map, was 30% or so high for several months.

Graham
Penzance

Graham

I don't know if there are any MO climatological sites or Environment Agency gauges down in your part of Cornwall?

The EA have a better network of automatic gauges across the country used to monitor rivers that we never get to see. I seem to remember there was one above Boscastle. A map of their locations would be handy so that you could ask to get archived rainfall data from one of them, but I've never seen one so perhaps I'll ask them.

As regards for that 1881-1915 which must have used rainfall data from the Symon's British Rainfall organisation I've just looked at the 1872 annual edition and it lists dozens of rainfall stations across west Devon and probably far more that they are now (excluding WOW of course).

http://www.metoffice.gov.uk/media/pdf/t/s/Symons's_British_Rainfall_1872.pdf

Bruce.

On Sunday, September 4, 2016 at 12:43:00 PM UTC+1, xmetman wrote:
On Sunday, 4 September 2016 12:02:41 UTC+1, Graham Easterling wrote:
On Sunday, September 4, 2016 at 11:19:53 AM UTC+1, xmetman wrote:
On Sunday, 4 September 2016 10:53:47 UTC+1, vidcapper wrote:
You might find this interesting, if a little out-of-date.

http://maps.nls.uk/geo/explore/#zoom...ers=10rain&b=1

You can switch between the old rainfall map & the modern one by using
the 'change transparency of overlay' slider.

I finally know why Capil Curig is so wet!


--

Paul Hyett, Cheltenham

Paul

I knew about this site, but had never noticed the 1881-1915 rainfall overlay.

Of course this begs the question if we have rainfall data to produce such a detailed map as this why do the Met Office only have a gridded data series that extends back to 1910?

Bruce.

A detailed map doesn't necessarily equate to accuracy. The MetO produce detailed actual and anomaly maps each month, showing rainfall in great detail over west Cornwall for instance. But where are the actual rainfall reports from? just Camborne & Culdrose. This can lead to some highly inaccurate maps, especially in summer. It was the extreme inaccuracy of these maps a few years back, that led me to realising Scilly was double recording rainfall. It still took them nearly 6 months from the time I reported it to correct it. The only reply I ever got was an unofficial private one, giving the reasons for the problem, in some detail - it was both interesting and disturbing (total lack of any reasonableness checks). I never got an official response.

It meant that the 'actual' figure for the Penzance area, presumably computed in some way from the Camborne & Scilly figures and a relief map, was 30% or so high for several months.

Graham
Penzance

Graham

I don't know if there are any MO climatological sites or Environment Agency gauges down in your part of Cornwall?

The EA have a better network of automatic gauges across the country used to monitor rivers that we never get to see. I seem to remember there was one above Boscastle. A map of their locations would be handy so that you could ask to get archived rainfall data from one of them, but I've never seen one so perhaps I'll ask them.

As regards for that 1881-1915 which must have used rainfall data from the Symon's British Rainfall organisation I've just looked at the 1872 annual edition and it lists dozens of rainfall stations across west Devon and probably far more that they are now (excluding WOW of course).

http://www.metoffice.gov.uk/media/pdf/t/s/Symons's_British_Rainfall_1872.pdf

Bruce.

Good point about EA stations. There's certainly one at Drift Dam, 2 miles WNW of Penzance. They also had one at Porthcurno, though I'm not sure if it still exists. They also have a gauge at Stithians, on the Lizard peninsula, not far from (but wetter than) Falmouth.

They have one near Boscastle. There were 2 similar floods at Boscastle in the 1950s, 1 affected a nearby gauge, the other didn't. I've seen photos from the river level in both floods, it was very similar. Because there's no reliable rainfall figure for 1 event, many more recent accounts of Boscastle 1950s floods incorrectly combine the 2 events into 1, it's become a forgotten flood.

In fact, Boscastle has been flooded severely many times. The most recent 1957, 1958, 1963 (all June) & 2004. The 2004 did most damage largely because of the cars being swept into bridges from the nice new NT rapid runoff car park on the flood plain. In 2004 204mm was recorded at Otterham - around 5 miles from Boscastle, and 184mm at Lesneweth, a bit further way. Incredible the EA were quite happy with the car park remaining, saying the flood was a once in 200 years event, I think they included an extra nought. Stephen Burt wrote a very good paper on the Boscastle 2004 flood, and put it into a much better historical perspective.

These north coast storms are far from uncommon, normally just to the east of headlands, which I think is typically down to 3 way convergence (sea breezes from north & west, against a gradient S wind. I've experienced a couple of storm that have dropped 100m or so in a short space of time. Here's an account of 1 http://www.turnstone-cottage.co.uk/SrMerrynStorm.PDF Once again June, the favoured month.

It's a real shame that we are loosing more and more reporting stations. So many WOW stations are innacurate and are in no way a replacement.

Graham
Penzance

"Graham Easterling" wrote in message
...
On Sunday, September 4, 2016 at 11:19:53 AM UTC+1, xmetman wrote:
On Sunday, 4 September 2016 10:53:47 UTC+1, vidcapper wrote:
You might find this interesting, if a little out-of-date.

http://maps.nls.uk/geo/explore/#zoom...ers=10rain&b=1

You can switch between the old rainfall map & the modern one by using
the 'change transparency of overlay' slider.

I finally know why Capil Curig is so wet!


--

Paul Hyett, Cheltenham

Paul

I knew about this site, but had never noticed the 1881-1915 rainfall
overlay.

Of course this begs the question if we have rainfall data to produce such
a detailed map as this why do the Met Office only have a gridded data
series that extends back to 1910?

Bruce.

A detailed map doesn't necessarily equate to accuracy. The MetO produce
detailed actual and anomaly maps each month, showing rainfall in great
detail over west Cornwall for instance. But where are the actual rainfall
reports from? just Camborne & Culdrose. This can lead to some highly
inaccurate maps, especially in summer. It was the extreme inaccuracy of
these maps a few years back, that led me to realising Scilly was double
recording rainfall. It still took them nearly 6 months from the time I
reported it to correct it. The only reply I ever got was an unofficial
private one, giving the reasons for the problem, in some detail - it was
both interesting and disturbing (total lack of any reasonableness checks). I
never got an official response.

It meant that the 'actual' figure for the Penzance area, presumably computed
in some way from the Camborne & Scilly figures and a relief map, was 30% or
so high for several months.

Graham
Penzance
================

It is computed from a combination of high-res radar and observations. There
is some adjustment for high ground according to wind direction. It is the
radar that will be the main source of errors. There have been a few
occasions recently of radar over-estimating rainfall in my locality. It gets
worse when Predanack goes AWOL. A far better map is produced in slow time in
collaboration with the EA using many more gauges, but that is not for public
consumption - sorry.

Will
--
" Some sects believe that the world was created 5000 years ago. Another sect
believes that it was created in 1910 "
http://www.lyneside.demon.co.uk/Hayt...antage_Pro.htm
Will Hand (Haytor, Devon, 1017 feet asl)
---------------------------------------------

On Sunday, 4 September 2016 10:53:47 UTC+1, vidcapper wrote:
You might find this interesting, if a little out-of-date.

http://maps.nls.uk/geo/explore/#zoom...ers=10rain&b=1

You can switch between the old rainfall map & the modern one by using
the 'change transparency of overlay' slider.

I finally know why Capil Curig is so wet!


--

Paul Hyett, Cheltenham

It's interesting that its altitude is only about 700 ft and it's in a valley but of course surrounded by a large area of very wet mountains. This effect is noticeable even in the valleys of the North Downs.

But can you pronounce it? :-)

Tudor Hughes, Warlingham, Surrey.