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Annual CET


SP1986
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Posted
  • Location: Broxbourne, Herts
  • Weather Preferences: Snow snow and snow
  • Location: Broxbourne, Herts
    On 11/03/2021 at 02:28, Relativistic said:

    It almost certainly won't be as cool as April or July 1713 this year. The last time the respective months were as cold were in 1922 and 1965. The other months are doable but it's hard to sustain prolonged below-average periods these days (the last time we did have such a period was precisely three centuries after 1713).

    Looking at the current models, it's a good job you said "it almost certainly won't" and not "it will never be" !  😀

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    Posted
  • Location: Edinburgh (previously Chelmsford and Birmingham)
  • Weather Preferences: Unseasonably cold weather (at all times of year), wind, and thunderstorms.
  • Location: Edinburgh (previously Chelmsford and Birmingham)
    27 minutes ago, Timmytour said:

    Looking at the current models, it's a good job you said "it almost certainly won't" and not "it will never be" !  😀

    I'm careful with my words for occasions such as this 😅

    Still a way to go yet though.

    Edited by Relativistic
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    Posted
  • Location: Scunthorpe
  • Location: Scunthorpe

    Looking at CET values so far for March 2021 and April 2021 up to the 17th

    March was 7.2C

    April so far 5.7C

    Anyone going to predict that April 2021 comes in overall colder than March 2021 by the time we have the whole month's data in?

    We must be in with a good chance of this since some cooler weather is predicted again from mid week onwards with overnight frosts making a comeback

    Edited by SqueakheartLW
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    • 2 weeks later...
    Posted
  • Location: Broxbourne, Herts
  • Weather Preferences: Snow snow and snow
  • Location: Broxbourne, Herts

    Well both March and February turned out to be considerably warmer than it looked like they would finish after 20 days of the month, but I think we can be reasonably certain now that April will not have such a dramatic turnaround.  Nevertheless despite its coolness it, along with March has not played ball with my 1713 comparison, so now I have moved onto 1915 - which produced an annual CET of 8.96C - as my next comparison for a sub 9C year. It looks like this April which I've estimated finishing at 6.8C will put them back on track though both taking a different daily path!


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    Posted
  • Location: Broxbourne, Herts
  • Weather Preferences: Snow snow and snow
  • Location: Broxbourne, Herts

     What is the optimum Annual CET for the UK?

    Obviously we have seen it increase considerably in the latter years, and no doubt this corresponds with the increase in global temperatures. I'm not sure how far back the measurement of global temperatures goes back, but thanks to the UK mean annual CET records we can see how the rolling 30 year average annual CET has increased dramatically since the early 1980s...


    image.thumb.png.765968fcc51855b0de3f59dfeba67c4a.png
     

    The rise in the last 40 years measures almost 0.8C  -  almost as dramatic as the rise that took place in the 40 year period in the years between 1700 and 1739 during which the rise measured almost as much as a 1C

    The rolling 30 year mean reached a peak in 1739 that was not reached again until 1947.   The average in 1739 - a high point for over 250 years, was  similar to what it was in 1981  - which has now become the low point of the last 40 years.

    Where we are currently in terms of annual CET is aligned to fears about the earth getting too warm.  But I wonder what the reaction of anybody tracking the CETS during the years of the earlier 18th century would have been?  Was that known to have also corresponded with an increase in global temperatures?  Would, given similar measuring and communication abilities, the period have sparked off fears about the earth warming up too much back then?

    If it were possible for man to control overall global temperatures by setting the rolling 30 year average annual  mean CET for the UK, where would you set it?

    I'm tempted to go with where it was in 1700 to increase the chances of getting my favourite type of weather, but I guess pitching it around the levels it was in 1739 and 1981 would be about right......  

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    Posted
  • Location: Edinburgh (previously Chelmsford and Birmingham)
  • Weather Preferences: Unseasonably cold weather (at all times of year), wind, and thunderstorms.
  • Location: Edinburgh (previously Chelmsford and Birmingham)

    I'd take the dip we had around 1700, with all of that due to cold winter periods. I'm quite happy for summer months to remain normal (in the sense of recent averages).

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    Posted
  • Location: Broxbourne, Herts
  • Weather Preferences: Snow snow and snow
  • Location: Broxbourne, Herts
    On 27/04/2021 at 18:45, Timmytour said:

    Well both March and February turned out to be considerably warmer than it looked like they would finish after 20 days of the month, but I think we can be reasonably certain now that April will not have such a dramatic turnaround.  Nevertheless despite its coolness it, along with March has not played ball with my 1713 comparison, so now I have moved onto 1915 - which produced an annual CET of 8.96C - as my next comparison for a sub 9C year. It looks like this April which I've estimated finishing at 6.8C will put them back on track though both taking a different daily path!


    image.thumb.png.04831ccf975e7cce74952f270e456054.png
     

    image.thumb.png.6176646997b15901cfda9bf687719390.png

    Updating this comparison of 1915 v 2021

    image.thumb.png.bf09d2b70ea31b1f508f5cad55a185e1.png

    image.thumb.png.8103bab7c141be2bcc04a798d7d752a6.png
     

    It will be going some to get under the 9C mark as only 4 years  where that was achieved have had a four month start that has been warmer than this year .... 1676, 1813, 1817 and 1890.

    1915 remains the closest to it and was just 0.3C colder in its aggregate monthly mean CETS upto April.  So we would need a year that carries on in a vein slightly colder than 1915. 1915 had a cool July and a cold November, but noting too untoward other than those two months.

     

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    Posted
  • Location: Edinburgh (previously Chelmsford and Birmingham)
  • Weather Preferences: Unseasonably cold weather (at all times of year), wind, and thunderstorms.
  • Location: Edinburgh (previously Chelmsford and Birmingham)

    Rolling CET for the past 12 months is 10.1C. A May mean of 11.0C or lower will take us sub-10C.

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    Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
    Posted (edited)

    It's impressive how quickly our CET has collapsed from its rolling value last year. 

    At 10.06C the rolling CET is the lowest since possibly Oct 15 (we got 10.09C in March 18). 

    Edited by summer blizzard
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    Posted
  • Location: Broxbourne, Herts
  • Weather Preferences: Snow snow and snow
  • Location: Broxbourne, Herts

    Apologies....repeating this post from the April CET as it may be something I'd want to come back to check on its progress and it would get lost in there (mind you I may be happy to see it get lost by the end of this month!)

    Quote

    A little table of values of monthly mean CETs of May to December from years that are not far removed in aggregate terms for January to April  from where we are at the moment, followed by picks for the rest of this year that could end up in an annual CET of under 9C

    For a couple of years I've shaved a few points off to allow for the fact that there is not otherwise enough leverage to bring the overall CET below 9c

    I've shown where the monthly mean is either part of its coldest 10% or its warmest 10%.  I've then tried to look at the values in 2021 for the rest of the year that could bring us an annual CET under 9C .

    It's unlikely we will get another month that joins April as a coldest 10% member bearing in mind we've only had three such months all century and the last year we had more than once such month was in 1991 when both February and June registered in their coldest 10%.  So while the picks used for the rest of the year are never really particularly warm, they are avoiding the extremely cold options....

     

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    image.png.79810eed21802b1866a0607cf6b382ab.png

     

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    • 2 weeks later...
    Posted
  • Location: Broxbourne, Herts
  • Weather Preferences: Snow snow and snow
  • Location: Broxbourne, Herts
    On 16/02/2021 at 20:00, Timmytour said:

    Will we ever get an annual CET below 9C again?   It might be argued that climate change will have put paid to it, but I'm not so sure.  Such years seem to come in clusters.  Mot recently we've had 1979 / 1985 / 1986  and before that 1956 / 1962 / 1963   .... a remarkably similar sequence of successive years following a six year wait!   The latter cluster was more impressive with another such year registering just two years later in 1965

    While 2010 was the last time we had such a year, which ended a run of 23 years and we are now currently on a run of 10 years.  But 1956 marked the end of a 33 year run while 1979 marked the end of an 13 year run so perhaps the run we are on isn't completely out of the "new" normal.  But prior to 1956 the longest ever such wait had been 14 years, culminating in the winters of 1740 and 1879.

    In earlier years there is undoubtedly a greater frequency of them, not just I suspect the respect of the cooler climate that existed back then, but also down to things like volcanic actions.  While there were a couple of VEI 5 volcanic eruptions around 1955 to 1957 I can't pinpoint a similar reasons for the cluster that began in 1979.  Maybe the eruptions of the Icelandic volcano in late March and early April 2010 had an impact on that  particular year, but it had already started on a pretty cold note.

    I think we will see one in the none too distant future....and perhaps a small cluster of them.  The combined CET for Jan and Feb looks like it might end up  cooler than  it was in 1962 despite the milder end to February currently showing  on the models, so it's possible that this could be the year! 

     

     

    1765902381_YearsWithoutaCETbelow9C.thumb.jpg.6ce83507b5f5bf743ffe56a05bdedabf.jpg 

    If we end up failing to get an annual mean CET below 9C this year, I don't think, looking at the current modelling, that I will be blaming May for it!

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    Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
    11 minutes ago, SLEETY said:

    how is the cet for this year still above average,when look at the met office stats ??

    https://www.metoffice.gov.uk/hadobs/hadcet/cet_info_mean.html

     

    They use the 1961-1990 average. 

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    Posted
  • Location: NR Worthing SE Coast
  • Location: NR Worthing SE Coast
    1 hour ago, summer blizzard said:

    They use the 1961-1990 average. 

    Anything to make it higher then,why are they not using the last 30 years instead🙄

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    Posted
  • Location: G.Manchester
  • Location: G.Manchester
    28 minutes ago, SLEETY said:

    Anything to make it higher then,why are they not using the last 30 years instead🙄

    WMO advises this as a baseline

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    Posted
  • Location: Irlam
  • Location: Irlam

    First 3 months of 2020, the CET averaged: 6.5C

    First 3 months of 2021, the CET averaged: 5.1C

    Yet, 2020 didn't record a single double digit CET daily mean in those 3 months whilst, 2021, recorded 7.

     

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    • 2 weeks later...
    Posted
  • Location: Broxbourne, Herts
  • Weather Preferences: Snow snow and snow
  • Location: Broxbourne, Herts
    On 01/05/2021 at 13:55, Timmytour said:

    Updating this comparison of 1915 v 2021

    image.thumb.png.bf09d2b70ea31b1f508f5cad55a185e1.png

    image.thumb.png.8103bab7c141be2bcc04a798d7d752a6.png
     

    It will be going some to get under the 9C mark as only 4 years  where that was achieved have had a four month start that has been warmer than this year .... 1676, 1813, 1817 and 1890.

    1915 remains the closest to it and was just 0.3C colder in its aggregate monthly mean CETS upto April.  So we would need a year that carries on in a vein slightly colder than 1915. 1915 had a cool July and a cold November, but noting too untoward other than those two months.

     

    Coming in at 10.1C, May has been by no means a let down in the quest for a sub 9C Annual Mean CET , and the overall comparisons with 1915 remain good, though there seems to be no correlation in the daily pattern of weather.

    May 1915 ended on a very cool note, precisely the opposite of May 2021.  But 1915 produced a June that was, while not particularly warm, was not outside the general average, so the warm start that June 2021 is making is not causing any undue alarm to the Seekers of the Sub 9C Brigade!

    image.thumb.png.59ab7ccf6af8cdb6295501a472a09e32.pngimage.thumb.png.86df1ca6857d551ee675b863fa586575.png 

     

      

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    Posted
  • Location: Ossett, West Yorkshire
  • Location: Ossett, West Yorkshire
    Posted (edited)

    I think anyone thinking that a sub 9*C annual CET is possible for 2021 is asking too much, as at this stage of 2021 so far, it would require something like a second half like 1993, or a repeat of Dec 2010 at the end of the year, both of which are very unlikely.  

    One point of note worth mentioning is that the rolling 12 month CET up to the end of May 2021, following the cool April and May we have just had, now stands at 9.87*C.  I believe that this is the first time since autumn 2015 that the rolling CET has gone under 10*C.

    Edited by North-Easterly Blast
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    Posted
  • Location: Broxbourne, Herts
  • Weather Preferences: Snow snow and snow
  • Location: Broxbourne, Herts
    50 minutes ago, North-Easterly Blast said:

    I think anyone thinking that a sub 9*C annual CET is possible for 2021 is asking too much, as at this stage of 2021 so far, it would require something like a second half like 1993, or a repeat of Dec 2010 at the end of the year, both of which are very unlikely.  

    One point of note worth mentioning is that the rolling 12 month CET up to the end of May 2021, following the cool April and May we have just had, now stands at 9.87*C.  I believe that this is the first time since autumn 2015 that the rolling CET has gone under 10*C.

    Not so sure anything particularly out of the ordinary is required, hence my comparison to 1915.  While it did deliver us a cool July and a cold November, the average across Nov and December was nothing remarkable . And this year has already given us the coldest May and April in many years so the coldest July for 33 years couldn't be ruled out! 

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    • 1 month later...
    Posted
  • Location: Broxbourne, Herts
  • Weather Preferences: Snow snow and snow
  • Location: Broxbourne, Herts
    Posted (edited)

    I think I am going to resign myself that the wait for another sub 9C annual mean CET is going to extend beyond this year.

    The aggregate mean CET for this year so far is 47.4C and there have only been six annual sub 9C CETs that have registered higher than 47C at this stage.

    That's not to say it's impossible....1813 was 47.3C at this stage and gave us an annual CET of 8.72C, so a repeat of its monthly CETS for this year would do the trick.....


    image.png.914bfd5ad40e24df2ddc95091cd27d24.png
     

    I'm not really seeing on the models any indication of July  - as disappointing at the outlook may currently seem on them - coming in lower than 16.  All months thereafter would need to be in their coldest 20th percentile which is not impossible but extremely unlikely!

    We've now had four years in the 20th Century that reached the halfway stage with an aggregate mean CET of less than 48C.   The others were

    2001......was 47.4C and ended up with an annual CET of 9.97C  partly thanks to a very warm October

    2010....  Was only 45C  and had its attempts to rise above an annual CET of 9C scuppered by the exceptionally cold December coming in finally at 8.86C.  Thus far it is the only year of this century without a single month breaking into its top ten warmest.   This year is currently on track to repeat that, but there is still a long way to go.

    2013......  The year of the remarkably cold March meant an aggregate mean CET of only 40.9C had been attained by the end of June.  However a strong recovery was made to register 9.61C in the end helped by a warm July, October and December.


     

    Edited by Timmytour
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    Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet

    Rolling CET rose to 9.88C for the July-June period.

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