May + June 2015: One of worst on record in Stornoway

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May + June 2015: One of worst on record in Stornoway

Postby Eddy Graham » 2015 Jun 30, 21:24

I've just computed the temperature, precip and sunshine values for Stornoway for May + June 2015, and compared these to the long-term (unhomogenised) series available for Stornoway, available from the Met Office at http://www.metoffice.gov.uk/pub/data/weather/uk/climate/stationdata/stornowaydata.txt.

The records show that May & June 2015 (combined) was:
- The 2nd wettest on record (and if we get another 7.6mm tonight [which is possible], we'll break the 143-yr record [infact, I'm not convinced that the 1877 record is fully legitimate])
- The 4th dullest (whilst acknowledging caveats of comparing pyranometer records with Campbell Stokes sunshine recorders - NB: there is a break in the series in 2004)
- And the 10th coolest (whilst acknowledging significant site changes since 1850s)

A few graphs showing these above stats are attached below...

(and still no sunshine today [30th June].. yet it reached 19C, the warmest day of the year so far)

Eddie Graham, Stornoway town.
May-June-2015_Temp.png
May-June-2015_Temp.png (16.24 KiB) Viewed 2251 times

May-June-2015_Precip.png
May-June-2015_Precip.png (7.75 KiB) Viewed 2251 times

May-June-2015_Sun.png
May-June-2015_Sun.png (9.69 KiB) Viewed 2251 times
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: May + June 2015: One of worst on record in Stornoway

Postby Len Wood » 2015 Jul 04, 15:50

Just shows how persistent the jetstream has been in your location Eddie.

In SW Devon, 550 miles south of you, rainfall in May and June has been average.
Temperatures have been a bit below average.

Rain
May 78.8 mm (ave 1986-2015, 62.6 mm)
June 54.4 mm (ave 1986-2015, 65.8mm)

Mean temp
May 12.09C (ave 2001-2010, 12.87C)
June 15.04C (ave 2001-2010, 15.42)
Len

Wembury, SW Devon coast
N50.33 W4.13
Altitude 83 m asl
Len Wood
 
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Location: Wembury, coastal SW Devon, 83 m asl

Re: May + June 2015: One of worst on record in Stornoway

Postby Jeffrey Blackshaw » 2015 Jul 05, 17:15

Eddie,

I could not agree with you more hence my letter in May's edition of the magazine re the exceptionally poor May here near Paisley in west of Scotland. We had 4 sunny days in June with the rest of the month following the trend set in May.

Jeff
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Re: May + June 2015: One of worst on record in Stornoway

Postby Eddy Graham » 2015 Oct 09, 20:06

Hi Everyone
Without wanting to 'cherry-pick'* the data too much, I recently determined the Poulter Index (Poulter 1962) for Stornoway's weather, for May, June and July this year. The result of all years 1929-2015 is shown in the graph (below) - and confirms what everyone on the Isles here already knows - that the early summer period brought unprecedented cool, wet and dull weather.
tn_Poulter-Index_MJJ.png
tn_Poulter-Index_MJJ.png (55.22 KiB) Viewed 2155 times

*I have chosen May, June, July (MJJ; in deference to the normal meteorological definition of summer as JJA), as the former have the longest daily lengths, and May is normally considered to be a 'summer' month in the Celtic fringes of Ireland and Scotland. Regardless of any definition of any season - the data still confirm that the May-July 2015 period this year was by far the 'worst' (most 'miserable') on record in Stornoway, since at least 1929, according to Poulter's index.

Eddie Graham, Stornoway, 9/10/2015

Reference:
Poulter, R. M. (1962). The next few summers in London. Weather, 17(8), 253-255.
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: May + June 2015: One of worst on record in Stornoway

Postby greg_gruner » 2015 Oct 09, 22:00

Hi Eddie
I hope October makes up for it. I know you've got a front hanging around up there now, but the forecast is for high pressure with easterly winds - should be great for the Western Isles.
Yet this is the month when we expect the rain and gales - shows how variable the British weather can be!
Greg
Greg Gruner
Farnborough, Hampshire
greg_gruner
 
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Re: May + June 2015: One of worst on record in Stornoway

Postby Eddy Graham » 2015 Oct 10, 09:50

Greg - September was a nice month here, with just one third of the average rainfall falling, slightly above average sunshine (105%) and only 10 wetdays. October had begun in the same vein (until yesterday, when we had rain most of the day with 12mm total to 9am this morning, it's still raining lightly this morning). To be honest, it's almost always 'Swings and Roundabouts' wrt the weather, so the weather simply had no option but to improve at some time or another!
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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