Deep low, 24 December 2013

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Re: Deep low, 24 December 2013

Postby Angus Tyner » 2013 Dec 23, 20:22

965.7mb, here in Ashford Co. Wicklow

only 3 times have I recorded lower, since Nov 1999
962.3 8th Nov 2010
963.3 24th Dec 1999
953.9 10th Mar 2008
Ashford Co. Wicklow
Met Eireann Climatological station number 975
COL station number EI018
My Weather Station
Angus Tyner
 
Posts: 35
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Location: Ashford Co. Wicklow eastern Ireland 12m asl

Re: Deep low, 24 December 2013

Postby Eddy Graham » 2013 Dec 23, 20:38

Stephen

The good news is that my barograph is now "safely" at my home, it is wound up, with new paper on this morning, and notched up +30hPa (I don't think 20hPa is enough!). I even brought home a spare ink head just in case. It is up in the "no children" zone in the loft of our house (so free from any potential bumps from my three young children). So assuming the slates and roof stays on the house (no kidding seriously, we are on a slight hill), hopefully we will have a good temporal record of the pressure pattern from here in Stornoway (I live about 4km due west of Stornoway Airport).

At 6:40pm, the pressure read 957hPa (i.e. 987hPa on the drum), after a fall of about 20hPa in past 6 hours. Air temp had risen to 6.1degC and rising fast still. Already we've had a dramatic day of weather: Ice everywhere and trace of snow to start at 09h, thaw by midday, heavy sleet, then heavy snow by 1:20pm (not settling, but blowing around wildly), slowly changing to rain as temp rose through by late pm. Wind gusty from E or SE, but hardly more than a gale at worst.

My immediate fear here is perhaps not of the wind (it seems to me that the models are not handling the forecast of the wind very well), but rather the rise of the sea that must be expected with air pressure dropping to sub-940hPa. From my Uni textbooks, ~30hPa drop = 1 metre rise in sea level. Thus, we might expect a high-tide of ~2.5m greater than normal tomorrow. High tide is expected at 11h00 and 23h00, or so. Much of Stornoway lies within + - 5m of sea-level. And this is not even accounting for the effects of the strong wind.

Anyway, let's wait & see. If you don't hear from me for a few days, it's because the power has gone... but also to say that I'll be tweeting regularly (@eddy_weather) and also updating my blog at: tinyurl.com/eddy-heb-weather

Eddie
p.s. Stephen; Assuming all goes to plan, once I am back to work in the New Year, I will gladly scan in the barogram trace (I don't have a scanner in the house).
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
 
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Location: Stornoway, Scotland

Re: Deep low, 24 December 2013

Postby Richard Hunt » 2013 Dec 23, 22:16

Air pressure is still dropping here.

At 2215 UTC its reading 973.2mb Falling Quickly. Could it beat my 966.0 mb record from March 2008 I wonder.
COL Station: 25020.

Watson W-8681 AWS. Standard Stevenson Screen. Maximum and Minimum screen thermometers. Grass minimum thermometer.
5" Copper standard rain gauge. Roof mounted annemometer.
Richard Hunt
 
Posts: 374
Joined: 2012 Jan 27, 19:23
Location: Hornsea, East Yorkshire. 10m AMSL

Re: Deep low, 24 December 2013

Postby Angus Tyner » 2013 Dec 23, 22:22

Angus Tyner wrote:965.7mb, here in Ashford Co. Wicklow

only 3 times have I recorded lower, since Nov 1999
962.3 8th Nov 2010
963.3 24th Dec 1999
953.9 10th Mar 2008


Now 962.9mb

This Dec record could well be broken on Friday!
Ashford Co. Wicklow
Met Eireann Climatological station number 975
COL station number EI018
My Weather Station
Angus Tyner
 
Posts: 35
Joined: 2012 Jan 27, 15:26
Location: Ashford Co. Wicklow eastern Ireland 12m asl

Re: Deep low, 24 December 2013

Postby Richard Hunt » 2013 Dec 24, 08:58

Pressure dropped to a minimum of 963.8mb which is the lowest of the year, and also the lowest for this site beating the 966.0mb I recorded in March 2008.

Wind gust reached 41 MPH overnight, with only 4.0mm of rainfall.
COL Station: 25020.

Watson W-8681 AWS. Standard Stevenson Screen. Maximum and Minimum screen thermometers. Grass minimum thermometer.
5" Copper standard rain gauge. Roof mounted annemometer.
Richard Hunt
 
Posts: 374
Joined: 2012 Jan 27, 19:23
Location: Hornsea, East Yorkshire. 10m AMSL

Re: Deep low, 24 December 2013

Postby Stephen Burt » 2013 Dec 24, 10:24

Lowest MSL pressure in the British Isles since December 1886

At 10h 937.0 mbar in South Uist, Hebrides. This surpasses the 937.6 mbar recorded at 0020 GMT on 20 December 1982 at Stornoway as the lowest authenticated MSL pressure in the British Isles since 8 December 1886, when 927.2 mbar was recorded at Belfast.

References
Burt SD. 1983. New UK 20th century low pressure extreme. Weather, 38: pp 208–213
Burt SD. 1983. The lowest of the Lows ... Extremes of barometric pressure in the British Isles, Part 1 – the deepest depressions. Weather, 62: pp 4-14
-----
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
 
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Joined: 2011 Dec 02, 19:36
Location: Stratfield Mortimer, Berkshire; a well-exposed rural site, 10 km SW of Reading

Re: Deep low, 24 December 2013

Postby brugge » 2013 Dec 24, 11:22

################################################################################
# SYNOPS from 03023, South Uist Range (United Kingdom) | 57-20N | 007-22W | 10 m
################################################################################
201312241100 AAXX 24114 03023 47460 /2140 10066 20048 39382 49387 55006 723//
333 82/17 90710 91159 91055=
201312241000 AAXX 24104 03023 47450 /2044 10053 20035 39381 49385 56016 781//
333 84/19 90710 91161 91056=

So 938.7 at 11h and 938.5 at 10h

Stephen, is this your South Uist station?

Roger
brugge
 
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Re: Deep low, 24 December 2013

Postby Stephen Burt » 2013 Dec 24, 12:06

Roger - it's the METAR from Benbecula, EGPL. At 0950 and 1020 reported 937 mbar - frustratingly, not to 1/10 mbar. Hopefully this will be logged on an AWS somewhere!

METAR/SPECI from EGPL, Benbecula (United Kingdom).
SA 24/12/2013 11:50->
METAR EGPL 241150Z 21030KT 9999 -SHRA SCT016 SCT026 07/05 Q0939=
SA 24/12/2013 11:20->
METAR EGPL 241120Z 20033G44KT 9999 -SHRA SCT012 SCT022 07/05 Q0938=
SA 24/12/2013 10:50->
METAR EGPL 241050Z 20032G42KT 9999 -SHRA SCT012 SCT020 06/05 Q0938=
SA 24/12/2013 10:20->
METAR EGPL 241020Z 19038G49KT 8000 -SHRA FEW018 BKN023 06/05 Q0937=
SA 24/12/2013 09:50->
METAR EGPL 240950Z 19039G49KT 8000 VCSH FEW015 SCT023 05/04 Q0937=
SA 24/12/2013 09:20->
METAR EGPL 240920Z 19039G52KT 8000 SHRA SCT015 BKN028 05/04 Q0938=
SA 24/12/2013 08:50->
METAR EGPL 240850Z 19036KT 9999 -SHRA FEW014 SCT018 BKN028 06/04 Q0939=
SA 24/12/2013 08:20->
METAR EGPL 240820Z NIL=
SA 24/12/2013 07:50->
METAR EGPL 240750Z 20038G49KT 9999 SHRA FEW018 BKN028 06/03 Q0939=
SA 24/12/2013 07:20->
METAR EGPL 240720Z 20035G47KT 9999 FEW018 BKN028 06/03 Q0939=
SA 24/12/2013 06:50->
METAR EGPL 240650Z AUTO 20036G48KT 9999 SCT023/// SCT031/// 06/03 Q0940=
SA 24/12/2013 06:20->
METAR EGPL 240620Z AUTO 20036G46KT 8000 -RA BKN019/// 05/03

At 03023, South Uist Range, lowest hourly synop ob 938.1 at 10h, still falling 016 then, 938.2 now rising at 11h, so the minimum probably just under 938 mbar.

Stornoway 11h 938.1 falling 020, so it might yet reach 937.5 before picking up.

Plotted meteocentre 10z chart: http://meteocentre.com/analyse/map.php? ... n&area=eur

SB
-----
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: Deep low, 24 December 2013

Postby Stephen Burt » 2013 Dec 24, 12:21

12z obs:

Stornoway synop (03026) 937.6 mbar, falling more quickly, 016

Stornoway Airport EGPO METAR 1150z 936 mbar.

So it looks as if the 1982 record has definitely been beaten, if only by a few tenths of a millibar.

SB
-----
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: Deep low, 24 December 2013

Postby brugge » 2013 Dec 24, 12:23

Thought I'd try the WOW website - pressure?
Black triangles, cut off 960 mb - very helpful, I must say!

I'll see if I can find anythingelse...

Roger
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