Weather

A typical British summer in the making

An expected return to more changeable weather through this week reminded me of the work of one of our best known and most respected climatologists Professor Hubert Lamb.

Professor Lamb is credited with discovering an empirical relationship between low solar activity and an increased probability of higher pressure in winter across more northern latitudes – which leads to colder winters across the UK and Europe.

Another part of his work was to analyse weather patterns over 100 years to try and see if any repeat themselves across the UK, with some success.

One of his main findings was a change of pattern from around the middle of June, which, in his words, saw the ‘return of the westerlies’.

By looking at climate data he discovered, more often than not, the Atlantic would re-assert itself around or just after mid-June, bringing changeable weather once more across our shores.

This would follow a period when westerly winds were at their weakest.

Climatologically this period is now called the ‘European monsoon’ as areas of low pressure move in from the west.

If the jet stream is behaving normally, this would mean wettest conditions in the north and west, with the least rainfall in the south and east.

Most of the time, but not always and hence the difficulty of using this as a long range forecasting tool, this changeable spell of weather would last well into July.

Lamb then discovered a second period in the climate records which tended to assert itself from mid to late July, which he called ‘thundery and cyclonic’ – in other words, less windy, warmer but with a risk of heavy showers.

This type of weather would then last well into August.

Lamb’s work effectively describes a typical British summer; one in which long spells of fine settled weather are the exception rather than the rule.

Although it’s early days, there are already indications that this summer is starting to resemble one of Professor Lamb’s typical British summers.

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  • Comment number 103. Posted by greensand

    on 17 Jun 2013 21:34

    #101. ashleyhr

    Crossed post, sorry did not check before posting!

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  • Comment number 102. Posted by greensand

    on 17 Jun 2013 21:31

    #100. newdwr54

    "I used the UK temperature data to obtain summer (JJA) temperature....."

    Do you have a link to the data DW?

    http://www.metoffice.gov.uk/climate/uk/datasets/Tmean/date/UK.txt

    Has: JJA

    2011 - 12.7 14.2 14.1 Ave 13.7
    2012 - 12.3 14.1 15.3 Ave 13.9

    2011-2012 Ave 13.8

    Do I have the wrong data set? Where am I going wrong?

    The above data set concurs within 0.1 of your other decadal numbers

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  • Comment number 101. Posted by ashleyhr

    on 17 Jun 2013 21:14

    newdwr54

    Thanks. I find your 2011-2012 figure very odd.
    The Summer 2011 Met Office UK mean was 13.66 C and that for 2012 was 13.93 C (both years did record a higher individual temperature on ONE day than all the previous four summers managed, but nevertheless they were cooler summers than the previous four overall).
    http://www.metoffice.gov.uk/climate/uk/datasets/Tmean/date/UK.txt
    The earlier figures are the sort of thing I would have expected, especially given all the rather hot summers between around 1989 and 2006.

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  • Comment number 100. Posted by newdwr54

    on 17 Jun 2013 20:25

    92. ashleyhr

    I used the UK temperature data to obtain summer (JJA) temperatures for all decades since the 1960s and for the start of this latest decade.

    I got:

    1961-1970: 13.5C
    1971-1980: 13.9C
    1981-1990: 14.0C
    1991-2000: 14.4C
    2001-2010: 14.7C
    2011-2012 : 14.8C

    Obviously it's too early to say whether this current decade will continue the steady upward trend in 10 year average UK summer temperatures, but it's started out in that direction.

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  • Comment number 99. Posted by QuaesoVeritas

    on 17 Jun 2013 20:21

    #97.greensand
    "Hi QV, I spotted this yesterday, on WUWT:-"

    Thanks, I wish I had seen that.

    Anyway it should have been easy to reply to my query, but no reply yet.

    It seems a long time to fix a MO server.

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  • Comment number 98. Posted by ashleyhr

    on 17 Jun 2013 18:17

    Next three days (away from the north west) - sticky and stormy with 28 C likely.

    Sunrise in Bromley at around 4.30 am today - overcast but with some clear sky very low to the north east. North eastern sky turned orange. Then it started raining. Rainbow in the south western sky. Very little sunshine either early on or later.

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  • Comment number 97. Posted by greensand

    on 17 Jun 2013 18:13

    #96.QuaesoVeritas

    Hi QV, I spotted this yesterday, on WUWT:-

    "I emailed the Met Office last week as the CET had stopped reporting on the 9th June. I got a reply the same day

    “Thank you for your email advising us that the Central England Temperature series is not reporting. Unfortunately the data is not available because the server that delivers this data has suffered a hardware failure.We hope to have the service restored by the end of next week.
    Please accept our apologies for any inconvenience caused.

    Kind Regards”

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  • Comment number 96. Posted by QuaesoVeritas

    on 17 Jun 2013 15:36

    I finally gave in and sent an email to the MO asking why the daily CET figures hadn't been updated since the 9th.
    Acknowledged but no reply as yet.

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  • Comment number 95. Posted by QuaesoVeritas

    on 17 Jun 2013 09:08

    #93.ashleyhr

    "Re 1967. I well remember two massive nighttime thunderstorms in the early hours of 14 July at Southport, Lancs (the previous day was very sultry and cloudy, I recall my parents remarking on the stickiness, and I gather there was a hailstorm, thunderstorm and - I think - a tornado in parts of Wiltshire on 13 July)."

    You seem to have a good memory for weather in particular years, which unfortunately I don't.
    I do remember when I was still at school, a particularly warm summer and playing an endless game of Monopoly on a friends lawn all day, which looking at the temperature figures for the NE, could have been 1959.
    I have a theory that one reason current climate researchers think that current weather patterns are unusual is that they can't remember the 1960's, being from a generation which was born in the 1970's and 1980's.
    However, that should be no excuse for Julia Slingo, since she was born in 1950.

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  • Comment number 94. Posted by waikuku

    on 17 Jun 2013 08:23

    ashleyhr 88

    Small world, I was within 20 miles of Cheltenham in early 70s. The spring of 72 had a spell (few days) of cold easterlies so much so that a friend who was washing his car one sunday in late march or early april ended up with ice forming from the rinse water on the tarmac surface.

    Apart from the summers of 75 and 76 I only recall mediocre summers throughout the whole decade although as is usual a few hot days did occur. For example I remember a 32C DAY at the start of July 1970 ending rapidly with thunderstorms and local flooding. (Watch out later this week).

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