Possible new high-altitude UK wind speed record

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Possible new high-altitude UK wind speed record

Postby Eddy Graham » 2015 Jan 20, 17:21

Folks - I've just had word from the MOD staff on St. Kilda that a gust of 82.9m/sec (185mph) was recorded during the recent 'hurricane'. I understand it was measured with a Gill Windsonic 2 (ultra-sonic) anemometer at their radar site on the island (which was eventually blown away), at an altitude of 350m. The staff themselves had to be evacuated by emergency helicopter at 3a.m. at the height of the storm. If accepted, this would be a new max wind record for a high altitude site in Scotland/UK (the current record is 173mph from Cairngorm summit on 20 March 1986). I am told that the anemometer has been taken down for testing and calibration before/if any official statement is made.

Eddie
Eddie Graham
Stornoway, Na h-Eileanan an Iar (Outer Hebrides), Scotland.

Stornoway town COL station, 20 AMSL, local records back to 1873.
Hebridean Weather Blog: http://bit.ly/1IFAPJa
Twitter Weather Feed: https://twitter.com/eddy_weather
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Re: Possible new high-altitude UK wind speed record

Postby Stephen Burt » 2015 Jan 25, 16:09

Hi Eddie -

It would be good to know more about this possible record - including details of the site (particularly anemometer height above ground), exposure (any factors likely to result in an increase in the observed wind speed, such as eddying or turbulence from nearby buildings or structures) and logging detail. The WMO spec for wind gusts is the 'highest 3 s running mean'; if the peak St Kilda value was logged over a shorter period then it would be considerably above 'standard' gust measurements (the average difference between a 3 s logged value and 1 s, for example, is about 5-8%, increasing to > 20% for a 0.25 s logged value: more on this in my book, pp 198-199).

Look forward to hearing more on this if and when you can source the information.

One thing that puzzles me, though - you said "The staff themselves had to be evacuated by emergency helicopter at 3a.m. at the height of the storm" - surely a wind of even 1/3 that value would be too hazardous to operate aircraft? Were they perhaps evacuated before the peak of the storm arrived?

I do recall a comment on the rainfall records sheets for St Kilda held within the Met Office archives, for a storm I think about 1954, which noted dryly 'Snowdon raingauge blown out of ground during the storm of (date) and not subsequently found despite a search." Indeed ... !

Stephen
-----
Stratfield Mortimer, Berkshire - central southern England
51.4°N, 1.0°W, 60 m AMSL, station grade A - AAAA47R
Records commenced here 1987 - local records available back to 1862
The Weather Observer's Handbook: www.measuringtheweather.com
Stephen Burt
 
Posts: 247
Joined: 2011 Dec 02, 19:36
Location: Stratfield Mortimer, Berkshire; a well-exposed rural site, 10 km SW of Reading

Re: Possible new high-altitude UK wind speed record

Postby Eddy Graham » 2015 Jan 26, 22:39

Dear Stephen

That report about the helicopter was puzzling me a bit too..(!) ..until I found out today that the '3am' value was a classic case of 'Chinese whispers' as passed down through social media here - a chap at the coastguard confirmed to me today that it was not until 3pm on the following afternoon that they were evacuated (when it was much calmer) - and so your intuition was correct. Indeed, I've never flown in a helicopter (as you may be able to guess quite clearly from my previous post!), but after reflection I suppose I can't quite imagine one trying to pick people up in Hurricane Force 12!

As for the site of St. Kilda (I've never been there either), but I understand it was at the site of the radar, on top of the 2nd highest hill (about 350m in altitude) - there is a path to it from the 'village' of St. Kilda (as seen on Google Earth). Now, yes of course there could be local accelerations, etc... but then again, these can happen over any peak, including the lovely dome-shaped Cairngorm summit too surely, where the current record stands? (I fear that if we took this point to the extreme, then one might argue why should we consider any wind data from mountain summits..?)

As for the specifics on wind gusts - I'm sorry but I don't have any further information, though I shall ask again and let you know if I find out more. I presume the Met Office will consider these as part of due course of their investigation. I have your book in my office, so I shall look up the pages you mention tomorrow, thanks for this

all the best
Eddie
p.s. The funnel actually blew off my Canadian rain gauge during the hurricane (though I found it later badly damaged in a neighbour's garden), but my copper rain gauge stayed firm thankfully.
Eddie Graham
Stornoway, Na h-Eileanan an Iar (Outer Hebrides), Scotland.

Stornoway town COL station, 20 AMSL, local records back to 1873.
Hebridean Weather Blog: http://bit.ly/1IFAPJa
Twitter Weather Feed: https://twitter.com/eddy_weather
Eddy Graham
 
Posts: 82
Joined: 2012 Jul 18, 17:09
Location: Stornoway, Scotland

Re: Possible new high-altitude UK wind speed record

Postby Niall Dollard » 2015 Jan 27, 00:32

There are a few images of the radar domes on this web page :

http://seakayakphoto.blogspot.ie/2011_0 ... chive.html

A little detail on the evacation :

http://www.hebrides-news.com/st-kilda-e ... 11115.html
www.kilkennyweather.com || COL Station No.: EI027
Niall Dollard
 
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Location: Kilkenny, Ireland

Re: Possible new high-altitude UK wind speed record

Postby Eddy Graham » 2015 Jan 27, 11:14

All

Further on this - please see attached photograph of the Gill console screen output from the wind anemometer on St. Kilda, showing the 82.9m/sec max wind gust.

tn_10921931_10152674555573100_233691174_n.jpg
tn_10921931_10152674555573100_233691174_n.jpg (19.85 KiB) Viewed 1049 times


Of course, this still proves nothing - though one would presume that the MOD/Qinetiq staff had sited the anemometer at the correct height (10m) and exposure, considering their (historic)links with the Met Office. Perhaps a COL member out there uses a Gill WindSonic 2 anemometer, and if so do they know what the default settings are for wind speed recording on these devices?

Also, the value on the image below 82.9m/s says "34.7" . I don't know if this is the maximum average wind speed (34.7m/sec = 78mph). If so, then this is a hurricane force 12, but the gust factor (gust divided by the average) would be an enormous 2.4; such a value would seem unlikely to me.

I have been told by a member of Qinetiq staff (who work for the MOD at the St. Kilda site) that they are now to' remain silent' on the issue - so I suppose either 1 of 2 things will happen:
(a) A new record will be confirmed (but this seems less likely as time goes on...)
(b) News on this will quietly fade without any comment being made

Personally, although the 'hurricane' was certainly an extraordinary storm - my own feeling is that a value of185mph is slightly 'high', as I would've expected winds of perhaps ~150mph at an altitude of 350m, with 180-190mph reserved for the freer troposphere at 1000m+ heights (such as at Cairngorm, which is much higher at 1200m) but we have no such high altitude weather stations in the Hebrides. For interest, Bealach na Ba (south of Ullapool) at an altitude of 773m recorded a max gust of 'only' 124mph, though the station lies in a col between the mountains and was not seemingly in the direct 'firing-line' of the sting jet (whereas St. Kilda and North Lewis apparently were).

Eddie
Eddie Graham
Stornoway, Na h-Eileanan an Iar (Outer Hebrides), Scotland.

Stornoway town COL station, 20 AMSL, local records back to 1873.
Hebridean Weather Blog: http://bit.ly/1IFAPJa
Twitter Weather Feed: https://twitter.com/eddy_weather
Eddy Graham
 
Posts: 82
Joined: 2012 Jul 18, 17:09
Location: Stornoway, Scotland

Re: Possible new high-altitude UK wind speed record

Postby Stephen Burt » 2015 Jan 28, 20:41

Thanks, Eddie - interesting background.

I suspect from the lack of publicity/confirmation from the Met Office that this measurement is suspect for whatever reason. I remember that the Saxa Vord gust of a similar value in the 31 Jan 1953 storm, in similar conditions, was eventually ruled out as a standard gust. I'll keep my ears to teh ground - let me know if anything else turns up!

Hope you've managed to right your screen too, btw ...

Stephen
-----
Stratfield Mortimer, Berkshire - central southern England
51.4°N, 1.0°W, 60 m AMSL, station grade A - AAAA47R
Records commenced here 1987 - local records available back to 1862
The Weather Observer's Handbook: www.measuringtheweather.com
Stephen Burt
 
Posts: 247
Joined: 2011 Dec 02, 19:36
Location: Stratfield Mortimer, Berkshire; a well-exposed rural site, 10 km SW of Reading

Re: Possible new high-altitude UK wind speed record

Postby Eddy Graham » 2015 Jan 31, 21:47

Hi again Stephen

Yes - that's what I'd reckon now too - I think perhaps the instruction to the staff to "keep silent" was probably a sign of some suspicion of the reading... a real pity if was something silly like wrong height / wrong mode of operation - as it was a certainly a rare storm, not to be missed.

Btw, I asked the Met Office recently for the records from 31/1/1953 and 13/2/1989: Somewhat surprisingly, Stornoway recorded 'only' 72knots (83mph) max gust on 31/1/1953 (when Orkney had 124mph), and 85 knots on 13/2/1989 (when Kinnaird lighthouse near Fraserburgh had 123knots / 142mph). In conversation with folk from around the island since the 'hurricane' (it is still on everyone's lips), most people mention the storms of 11-12/1/2005, 13/2/1989 and 31/1/1953 (if they are old enough) as direct comparisons. Interestingly, after looking closely through the Met Office documents & another, I see that the Stornoway anemometer had some problems between 1952-54, necessitating constant repair...

As for my screen - it is happily righted and back in position now. As I type (21h40 on 31/1/2015), the temp is +2.1C, but the bitter north wind continues, the ground has frozen again (due to ice-bulb effect) and there is a trace of graupel/snow lying; we may yet have a snow cover by morning. Even without the 'hurricane' of the 9th, January 2015 has been another memorable month, the 2nd wettest of any month since I arrived here in 2009 (total of ~249mm; 2nd only to Dec 2013 with 307mm). Snow lay on 10 mornings (with 4 separate thaws and 4 fresh snowfalls, but none more than 5cm in depth), and there were 3 days with thunder. Lowest temp was only -2.2C on 20th, highest 10.6C on 25th. Mean temp of +4.2C is -0.7C below Stornoway Airport's 1981-2010 Jan average, but within -0.15C of the long-term 1873-2010 Stornoway area average.

All the best
Eddie
Eddie Graham
Stornoway, Na h-Eileanan an Iar (Outer Hebrides), Scotland.

Stornoway town COL station, 20 AMSL, local records back to 1873.
Hebridean Weather Blog: http://bit.ly/1IFAPJa
Twitter Weather Feed: https://twitter.com/eddy_weather
Eddy Graham
 
Posts: 82
Joined: 2012 Jul 18, 17:09
Location: Stornoway, Scotland


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