Hi

Sharp little trough just passed through mid-Devon at 0912. Well marked on the visible satellite images from the 15 minute DataPoint site (shame that from today we now will only get them every 3 hours) with a gust to 37 knots (add 30% its a Vantage Pro) and a rainfall rate of 60 mm per hour for a minute or so. Some red pixels on the rainfall radar - don't see any CB evidence at the moment but they must be there.

Bruce.

"Bruce" wrote in message
...
Hi

Sharp little trough just passed through mid-Devon at 0912. Well marked on
the visible satellite images from the 15 minute DataPoint site (shame that
from today we now will only get them every 3 hours) with a gust to 37 knots
(add 30% its a Vantage Pro) and a rainfall rate of 60 mm per hour for a
minute or so. Some red pixels on the rainfall radar - don't see any CB
evidence at the moment but they must be there.

Bruce.
==================

Damp squib here Bruce. Just a short burst of light rain to add to the 209 mm
collected so far this month.

Will
--
http://www.lyneside.demon.co.uk/Hayt...antage_Pro.htm
Will Hand (Haytor, Devon, 1017 feet asl)
---------------------------------------------

On 31/01/2013 09:37, Bruce wrote:
Hi

Sharp little trough just passed through mid-Devon at 0912. Well marked on the visible satellite images from the 15 minute DataPoint site (shame that from today we now will only get them every 3 hours) with a gust to 37 knots (add 30% its a Vantage Pro) and a rainfall rate of 60 mm per hour for a minute or so. Some red pixels on the rainfall radar - don't see any CB evidence at the moment but they must be there.

Bruce.


Passed through here at exactly the same time 0912 accompanied by hail,
strong gusty wind and a sharp temperature drop (9.5C to 5.4C).

--
Sutton Courtenay, Oxon. 59m asl

"Bruce" wrote in message
...

Hi

a gust to 37 knots (add 30% its a Vantage Pro)

Can anyone explain that statement?
Gusting 43KT here, so does that mean 56KT?? That's a big stab in the dark!
Ken
Copley, Teesdale

"Ken Cook" wrote in message ...

"Bruce" wrote in message
...

Hi

a gust to 37 knots (add 30% its a Vantage Pro)

Can anyone explain that statement?
Gusting 43KT here, so does that mean 56KT?? That's a big stab in the dark!
Ken
Copley, Teesdale

-----------------------

Usually down to anemometer exposure/height so may be a correction to 10m.
All the data I'm aware of suggests the VP2 (as it would be nowadays of
course) captures 2.25sec wind gusts accurately (or at least within the 5%
specification).

John Dann
www.weatherstations.co.uk

Hi

a gust to 37 knots (add 30% its a Vantage Pro)

Can anyone explain that statement?
Gusting 43KT here, so does that mean 56KT?? That's a big stab in the dark!
Ken
Copley, Teesdale

-----------------------

Usually down to anemometer exposure/height so may be a correction to 10m.
All the data I'm aware of suggests the VP2 (as it would be nowadays of
course) captures 2.25sec wind gusts accurately (or at least within the 5%
specification).

Hi, John,
Thanks for your reply. The statement above states (add 30% it's a Vantage
Pro) rather than (add 30% for height) so I assume that means a Vantage Pro's
readings need an adjustment of +30% whatever the height, in Bruce's opinion.
Best wishes
Ken

On Thursday, January 31, 2013 9:37:03 AM UTC, Bruce wrote:
Hi



Sharp little trough just passed through mid-Devon at 0912. Well marked on the visible satellite images from the 15 minute DataPoint site (shame that from today we now will only get them every 3 hours) with a gust to 37 knots (add 30% its a Vantage Pro) and a rainfall rate of 60 mm per hour for a minute or so. Some red pixels on the rainfall radar - don't see any CB evidence at the moment but they must be there.



Bruce.

Dear All

I seemed to have caused a bit of a stir with Vantage Pro users! In best Blue Peter tradition I was going to unveil a link to a PDF that I had downloaded on the internet over 5 years ago that ran a full and comprehensive comparison of its main features i.e. wind, pressure, rain & temperature. You'll have to take my word for it now - but some were better than others - but it did under read wind speed - perhaps by not as much as my 30% but it was still high. I would obviously like to back that up with the evidence - but as I say I can't lay my hands on the document despite a good rummage around my backup CD's.

I've had a Vantage Pro myself since 2004 and although it was expensive initially, as each year passes by the cost reduces from £1000/1 to now £1000/9 which is not bad value for money even though the UV sensor has not been working for years!

My anemometer is not at all in a standard site - it sits a top our chimney at around 10 or 12 metres. We are in a well sheltered spot but I just know from a good many years of airfield observing (including weekly checks of the anemometer using the Beaufort scale and wind sock) that its just too low - this may not sound very scientific - but it may catch the extreme gusts better but not general mean. For instance yesterday was a VERY windy day in this part of Devon - mean speed for the day was 5.1kts with a gust to 30.4kts. Today I have a mean of 9.0kts with a gust to 36.5kts which is very high for here - As a rule of thumb I know when there's been a gale here if it means over 10kts for the day and that happens very rarely.

Perhaps its because I've analysed many thousands of hours of anemograph trace when working an observer that I know its just too low.

What of course I would like to do is to buy and replace my Vantage Pro with the Vaisala 'Hawk' WXT510 and just see how they compared but I'm still waiting for that elusive lottery win!

http://www.vaisala.com/en/products/m...es/WXT520.aspx

Bruce.

PS Its a shame that Davis never let you add a fudge factor to the wind speed like they do with RH - but I suppose that would be like admitting it may not be correct in the first place.

On 31/01/2013 09:37, Bruce wrote:
Hi

Sharp little trough just passed through mid-Devon at 0912. Well marked on the visible satellite images from the 15 minute DataPoint site (shame that from today we now will only get them every 3 hours) with a gust to 37 knots (add 30% its a Vantage Pro) and a rainfall rate of 60 mm per hour for a minute or so. Some red pixels on the rainfall radar - don't see any CB evidence at the moment but they must be there.

Nothing at all here, just a bit of cloud passed through causing the
sunshine recorder to turn off from 09:30 to 09:50. No rain and the
maximum gust at that time was 24 mph, which was typical of the gusts for
most of the morning. The temperature remained pretty constant at around
10°C but then picked up at 10:45 to reach a maximum of 11.7°C today.

--
Nick G
Otter Valley, Devon
20 m amsl
http://www.ottervalley.co.uk