On Mon, 8 Feb 2016 02:24:07 -0800 (PST), xmetman wrote:

On Monday, 8 February 2016 09:21:57 UTC, Graham Easterling wrote:
On Monday, February 8, 2016 at 8:51:24 AM UTC, xmetman wrote:
On Monday, 8 February 2016 08:41:23 UTC, Graham Easterling wrote:
Gust of 86mph at Land's End. Mean speed reached 67mph!

Wind WNW offshore here, but still a gust of 59mph, the strongest in a W-NW wind since November 2009.

Given the time of high tides, I think 6pm is a strange time to remove the warning. Significant (not maximum!) swell height now 30' at Sevenstones. Easily the biggest since 2014.

Graham
Penzance

Graham

Where do you get that observation for Lands End from?

Bruce.

It's here http://www.landsendweather.info/met/mainframe.htm . It's actually the Porthgwarra side of Land's End, near Gwennap Head. It's run by John Chappell

I see from your list Culdrose reached 79mph. I think most of the the west Penwith peninsula has seen gust well 70mph (ways from sheltered Newlyn/Penzance). 76mph gust at St Ives.

Under these conditions the webcams are useless, covered in salt http://magicseaweed.com/Live-Sennen-Webcam/65/ vut I hope to get to Sennen this afternoon and hopefully post some pics lately.

I think the real flooding issues will be on this afternoons high tide, the swell was smaller on the last one, and the period is getting longer now.

Graham
Penzance

Graham

I can see the site and the anemometer and vane using Google street view. Mean speeds as high as 67 and gust to 86 mph will cause damage and look a tad high to me.

It got me to thinking about cup size of my Vantage Pro. I've just checked mine and realised that I've had it on 'small' cups for many years (oops!), I had thought it would default to 'large' (wrong!). I don't know how much difference that will make to the speed, probably not a lot.

The upper air station at Camborne (81 M amsl) was meaning (at 09 UTC) 44 mph with gusts to 65 mph, that still can't match the latest live mean wind speeds from Trebehor (270' ASL).

I suppose the Vantage Pro just collects 1 minute mean speeds and graphs those values in its own LCD display, and it's down to the display software on the PC to take the average of 10 of those one-minute values to produce a 10 minute mean. A one minute mean of 67 mph would be significantly higher than a 10 minute mean (~x1.2 or more higher). The length of that mean should be a user setting I would have thought and I bet it's not 10.

Bruce.


Bruce,

The Vantage Pro console receives a wind measurement from the anemometer
sensorevery 2.5 seconds. That is the ever-changing figure that is displayed on
the console. It calculates a rolling 10-min mean from those figures which can be
displayed in the text bar on the bottom of the console screen. There are other
options for that text bar.

A random 1-min mean wind speed may be higher or lower than a corresponding
10-min mean within which it is embedded.

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
http://peakdistrictweather.org