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The "new normals" for 1991-2020 (CET) now updated through December


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Posted
  • Location: Rossland BC Canada
  • Location: Rossland BC Canada

This thread will track the emerging next set of 30-year normals to replace the 1981-2010 CET values, which are shown below, followed by what we have to date (1991-2019 for Jan to July and 1991-2018 for Aug-Dec and annual). The July 2019 value is projected from current tracking as 17.5 and this will be adjusted in edits later this month. 

What follows the list of almost completed 1991-2020 averages will be final values that would occur for ranges of plausible values in 2020 (for Jan-July) or average of 2019-20 for Aug-Dec and annual. The thread will be maintained and edited so that these ranges shrink down to 2020 values by January, and we welcome in the new normals one by one during 2020 (subject to official verification when close to the rounding boundaries). 

(18 Apr 2020 _ updated with January to March 2020 now provisionally complete, awaiting Met Office confirmation.)

(01 Sep 2020 _ updated with April to August 2020 now provisionally complete, awaiting Met Office confirmation. Both March and April are almost equally likely to be 0.1 different, 6.8 and 8.9 being the alternates, based on slightly different methodology used by them and myself as explained).

(02 Dec 2020 _ updated Sept, Oct, Nov as shown)

_______ Jan _ Feb _ Mar _ Apr _ May _ Jun _ Jul _ Aug _ Sep _ Oct _ Nov _ Dec __ YEAR

1981-2010 _ 4.4 _ 4.4 _ 6.6 _ 8.5 _11.7 _14.4 _16.7 _16.4 _14.0 _10.7 _7.1 _ 4.6 ___ 10.0

1991-2020 _ 4.7 _ 4.9 _ 6.7 _ 9.0?_11.9_14.7 _16.8 _16.5 _ 14.2 _ 10.9 _7.4_5.0 ___ 10.2

 

JAN has ended up 4.7 (from 4.66).

FEB has ended up 4.9 (from 4.89). 

MAR will end up 6.7 or possibly 6.8, wait and see what Met Office says, my average is 6.74 so any differentials produced by average of max and min instead of monthly means could change it.

APR will end up either 8.9 or 9.0 as my method gives 8.947 as the average, the Met Office calculates from mean max and mean min, whereas my tracking is an average of thirty monthly means. There can be differences especially with these cases very close to dividing lines. 

MAY has ended up 11.9 (from 11.90). 

JUN has ended up 14.7 (from 14.69). 

JUL has ended up 16.8 (from 16.79). 

AUG has ended up 16.5 (from 16.51). .

SEP has ended up 14.2 (from 14.17). 

OCT has ended up 10.9 (from 10.93). 

NOV has ended up at 7.4 (from 7.41).

DEC has ended up 5.0 (from 4.97).

and the ANNUAL has settled at 10.2 (from 10.23), 

All of these stats will be updated by edit going forward. 

Edited by Roger J Smith
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Posted
  • Location: Rossland BC Canada
  • Location: Rossland BC Canada

I have not been tracking that aspect, J10, maybe somebody reading this could provide some insights. I also had that perception about max rising a bit slower than min during this half century of warming. May be more applicable to warmer half of the year. 

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Posted
  • Location: Hounslow, London
  • Weather Preferences: Csa/Csb
  • Location: Hounslow, London

Here are the averages from London for 1989-2018, so the 1991-2020 averages should be very similar.

image.png.dd48bf52686533a7761c8032d1934a

Slightly warmer, wetter and cloudier than the 1981-2010 averages.

Edited by B87
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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)

A brief glance at the annual data (lower graphs on the right) seems to suggest that the opposite is true, i.e. maxima are increasing more rapidly than minima.

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

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

Will do some quantitative analysis if I can find the time.

Edited by Relativistic
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Posted
  • Location: Leeds
  • Weather Preferences: snow, heat, thunderstorms
  • Location: Leeds

Interesting that July, August and September have each only increased by 1C.

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Posted
  • Location: Lincoln, Lincolnshire
  • Weather Preferences: Sunshine, convective precipitation, snow, thunderstorms, "episodic" months.
  • Location: Lincoln, Lincolnshire
27 minutes ago, J10 said:

Roger, do you have the Minimum and Maximum temps, as it is often mentioned that temps overnight  have risen quicker than Maximum temps.

In the UK it is the other way round at the official MetO observing network - maximum temperatures have generally increased faster than minimum temperatures.  I get a sense that this shift occurred in the 1990s and 2000s, associated with a decrease in cloud cover, and that we may see the maxima and minima both go up by a similar amount from 1981-2010 to 1991-2020.  That said, in many of the expanding populated areas of the UK the mean minimum temperature has risen more quickly due to the urban heat island effect.

Edit: I see Relativistic beat me to it!

Edited by Thundery wintry showers
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Trends.xlsxLooking into this further, Relativistic and Ian are both correct.

Max Temps have risen by an additional 0.1c (roughly) compared to Min Temps per decade.

At least though I have learnt something from my incorrect assumption.

MeanTempJAN  FEB  MAR APR  MAY  JUNE   JULY  AUG    SEP   OCT   NOV  DEC YEAR   INC
1961-1990 3.81  3.76  5.68  7.89  11.16  14.16  16.05  15.77  13.60  10.62  6.55  4.65    9.51
1971-2000 4.20  4.24  6.27  8.07  11.31  14.07  16.48  16.21  13.71  10.41  6.87  5.06    9.77      0.26
1981-2010 4.44  4.39  6.58  8.52  11.66  14.48  16.71  16.41  14.03  10.69  7.14  4.63  10.00      0.23
1991-2020 4.60  4.84  6.74  8.90  11.88  14.67  16.82  16.45  14.18  10.96  7.42  4.94  10.22      0.22

Min Temp JAN  FEB  MAR APR MAY  JUNE  JULY AUG  SEP  OCT  NOV DEC YEAR  INC
1961-1990 1.21  0.96  2.26  3.96  6.75    9.73  11.68 11.46   9.64  7.20  3.64  2.04  5.91
1971-2000 1.56  1.32  2.90  4.08  6.78    9.69  11.94 11.71   9.75  7.00  3.94  2.46  6.12     0.22
1981-2010 1.75  1.38  3.08  4.30  7.13  10.02  12.17 11.95 10.02  7.29  4.24  1.96  6.30     0.18
1991-2020 1.91  1.79  3.09  4.57  7.33  10.11  12.18 12.04 10.12  7.55  4.48  2.20  6.48     0.17

Max Temp JAN  FEB  MAR  APR  MAY  JUNE  JULY  AUG   SEP   OCT   NOV  DEC YEAR  INC
1961-1990 6.44  6.56  9.08  11.82 15.56 18.57  20.41  20.08  17.56 14.02   9.45   7.29  13.11
1971-2000 6.86  7.13  9.63  12.06 15.81 18.41  20.98  20.71 17.68  13.80   9.80   7.69  13.41   0.30
1981-2010 7.15  7.36 10.07 12.72 16.16 18.91  21.23  20.85 18.05  14.08 10.06   7.32  13.70   0.29
1991-2020 7.31  7.86 10.38 13.22 16.40 19.22  21.45  20.86 18.25  14.37 10.36   7.68  13.97   0.27

 

 

Edited by J10
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Posted
  • Location: Rossland BC Canada
  • Location: Rossland BC Canada

Thanks for adding those details. Interesting. 

Meanwhile, the July CET was in fact 17.5 so no edits required to the tracking. It will take a warmer July than this year to produce a new normal of 16.9, otherwise it's likely to remain 16.8. 

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  • 2 months later...
Posted
  • Location: Rossland BC Canada
  • Location: Rossland BC Canada

The tables have been updated for confirmed August and September values.

The commentary about projections for 1991-2020 have been updated now that we know the needed values for various outcomes for those months.

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Posted
  • Location: Wildwood, Stafford 104m asl
  • Weather Preferences: obviously snow!
  • Location: Wildwood, Stafford 104m asl
On 31/07/2019 at 22:10, cheese said:

Interesting that July, August and September have each only increased by 1C.

hmmmmmmmmm yes, was just going to post something like that, more so no surprise that the 'snow possible' months have the biggest increase

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Posted
  • Location: Edmonton Alberta(via Chelmsford, Exeter & Calgary)
  • Weather Preferences: Sunshine and 15-25c
  • Location: Edmonton Alberta(via Chelmsford, Exeter & Calgary)

Here in Edmonton the warming seems to be confined to the winter...Dec-Mar has warmed by 1.5-2c ..yet the rest of the year has shown no real deviation from the 1937-90 data..the winters it seems have become drier and sunnier..where as the rest of the year precipitation and sunshine remains the same.

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  • 1 month later...
Posted
  • Location: Rossland BC Canada
  • Location: Rossland BC Canada

I just remembered to update this thread for October. The rather cold (10.0) CET has shifted the range of Oct 2020 values now required to boost the current 29-year average of 10.9 into the 11.0 range. October 2020 will have to manage 11.5 to any record high value below 14.4 to reach 11.0 for the new normal. Otherwise if it can stay between 8.5 and 11.4, it will end up staying where it is now at 10.9. Next update after November CET is confirmed. 

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Posted
  • Location: Weston-S-Mare North Somerset
  • Weather Preferences: Hot sunny , cold and snowy, thunderstorms
  • Location: Weston-S-Mare North Somerset

If I'm reading that correct, then we have only increased 0.71c in the last 60yrs?

 

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Posted
  • Location: Solihull, West Midlands. - 131 m asl
  • Weather Preferences: Sun, Snow and Storms
  • Location: Solihull, West Midlands. - 131 m asl
On 01/08/2019 at 20:07, J10 said:

Trends.xlsxLooking into this further, Relativistic and Ian are both correct.

Max Temps have risen by an additional 0.1c (roughly) compared to Min Temps per decade.

At least though I have learnt something from my incorrect assumption.

MeanTempJAN  FEB  MAR APR  MAY  JUNE   JULY  AUG    SEP   OCT   NOV  DEC YEAR   INC
1961-1990 3.81  3.76  5.68  7.89  11.16  14.16  16.05  15.77  13.60  10.62  6.55  4.65    9.51
1971-2000 4.20  4.24  6.27  8.07  11.31  14.07  16.48  16.21  13.71  10.41  6.87  5.06    9.77      0.26
1981-2010 4.44  4.39  6.58  8.52  11.66  14.48  16.71  16.41  14.03  10.69  7.14  4.63  10.00      0.23
1991-2020 4.60  4.84  6.74  8.90  11.88  14.67  16.82  16.45  14.18  10.96  7.42  4.94  10.22      0.22

Min Temp JAN  FEB  MAR APR MAY  JUNE  JULY AUG  SEP  OCT  NOV DEC YEAR  INC
1961-1990 1.21  0.96  2.26  3.96  6.75    9.73  11.68 11.46   9.64  7.20  3.64  2.04  5.91
1971-2000 1.56  1.32  2.90  4.08  6.78    9.69  11.94 11.71   9.75  7.00  3.94  2.46  6.12     0.22
1981-2010 1.75  1.38  3.08  4.30  7.13  10.02  12.17 11.95 10.02  7.29  4.24  1.96  6.30     0.18
1991-2020 1.91  1.79  3.09  4.57  7.33  10.11  12.18 12.04 10.12  7.55  4.48  2.20  6.48     0.17

Max Temp JAN  FEB  MAR  APR  MAY  JUNE  JULY  AUG   SEP   OCT   NOV  DEC YEAR  INC
1961-1990 6.44  6.56  9.08  11.82 15.56 18.57  20.41  20.08  17.56 14.02   9.45   7.29  13.11
1971-2000 6.86  7.13  9.63  12.06 15.81 18.41  20.98  20.71 17.68  13.80   9.80   7.69  13.41   0.30
1981-2010 7.15  7.36 10.07 12.72 16.16 18.91  21.23  20.85 18.05  14.08 10.06   7.32  13.70   0.29
1991-2020 7.31  7.86 10.38 13.22 16.40 19.22  21.45  20.86 18.25  14.37 10.36   7.68  13.97   0.27

 

 

J10..

Any chance of sending out the updated xlsx file with the updated figures for Oct ?

Thanks

MIA

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  • 2 weeks later...
Posted
  • Location: Rossland BC Canada
  • Location: Rossland BC Canada

I have updated the first post of the thread with data from Nov 2019 (6.2). This rather cold value now means that Nov 2020 will have to finish 6.6 to 9.5 to stay on 7.4, as we are now at about 7.36. Anything plausible colder than 6.6 will make 7.3 the new value. A really warm November could take us to 7.5. 

SteveB, here's the full breakdown of 30-year averages since 1901-30 for your interest. If you want to see earlier values, look in my historical CET thread in the historical weather section.

Some of my values may round 0.1 different from Met Office values because I think they derive them from an average of 30-year mean max and mean min. Also you get into third decimal issues about rounding from .x5 situations. But this gives the general picture of what's been happening in the recent past. 

Interval __________JAN __ FEB __ MAR _ APR _ MAY _ JUN __ JUL __ AUG __ SEP __ OCT _ NOV _ DEC __ YEAR

 

1901-1930________4.2 ___4.2 ___5.5 ___8.0 __ 11.3 __ 13.8 __ 15.8 __ 15.2 __ 13.1 ___9.8 ___5.8 ___4.5 ___ 9.2

1911-1940________4.2 ___4.3 ___5.7 ___8.2 __ 11.5 __ 14.2 __ 15.9 __ 15.6 __ 13.3 ___9.6 ___6.2 ___4.6 ___ 9.4

1921-1950________3.9 ___4.2 ___5.9 ___8.0 __ 11.3 __ 14.4 __ 16.3 __ 15.9 __ 13.6 __10.0 ___6.4 ___4.5 ___ 9.5

1931-1960________3.5 ___3.9 ___5.9 ___8.1 __ 11.5 __ 14.6 __ 16.2 __ 16.0 __ 13.7 __10.1 ___6.8 ___4.7 ___ 9.6

1941-1970________3.3 ___3.6 ___5.7 ___8.1 __ 11.4 __ 14.5 __ 16.0 __ 15.7 __ 13.7 __10.6 ___6.6 ___4.4 ___ 9.5

1951-1980________3.6 ___3.7 ___5.6 ___8.0 __ 11.3 __ 14.3 __ 15.9 __ 15.6 __ 13.6 __10.5 ___6.6 ___4.7 ___ 9.4

1961-1990________3.9 ___3.7 ___5.7 ___7.9 __ 11.1 __ 14.1 __ 16.1 __ 15.8 __ 13.6 __10.6 ___6.5 ___4.7 ___ 9.5

1971-2000________4.2 ___4.2 ___6.3 ___8.1 __ 11.3 __ 14.1 __ 16.5 __ 16.2 __ 13.7 __10.4 ___6.9 ___5.1 ___ 9.7

1981-2010________4.4 ___4.4 ___6.6 ___8.5 __ 11.7 __ 14.5 __ 16.7 __ 16.4 __ 14.0 __10.7 ___7.1 ___4.6 __ 10.0

=============================================================================================

Trends in the above data reveal that Jan and Feb were milder in the first half of the 20th century than around 1941-80, and we were only edging past those values by 1981-2010.

Spring, summer and autumn showed somewhat the opposite trend until the recent warming began. 

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  • 1 month later...
Posted
  • Location: Rossland BC Canada
  • Location: Rossland BC Canada

I updated the first post with the information adjusted for December after that finished 5.8 in 2019.

Basically, December is quite likely to finish with a 5.0 mean, as long as Dec 2020 is in the range 4.3 to 7.2. 

It is worth pointing out that my calculations will not exactly match the Met Office numbers, as they appear to be calculating normals (as they should) from the mean maximum and mean minimum values for the thirty years. This should only introduce a tiny variability factor, since I am taking the mean of monthly means (which are themselves averages of max and min). I noticed that if my calculations are very close to a rounding point, for example with May 1961-1990, I got 11.2 using my method and they got 11.1, but I was rounding up from something like 11.151, probably they had something like 11.149. 

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Posted
  • Location: Lincoln, Lincolnshire
  • Weather Preferences: Sunshine, convective precipitation, snow, thunderstorms, "episodic" months.
  • Location: Lincoln, Lincolnshire
On 19/11/2019 at 10:11, SteveB said:

If I'm reading that correct, then we have only increased 0.71c in the last 60yrs?

 

It doesn't work that way because Roger's analysis is comparing decadal shifts in 30-year means, but interestingly the 60-year trend could be derived by comparing 1991-2020 with 1931-1960, in which case you'd get slightly less than 0.71C of warming (the figures point to nearer 0.6C, or a mean trend of 0.1C per decade).  In common with the Northern Hemisphere as a whole, England saw a relatively warm phase around the 1940s, leading to 1931-1960 being slightly warmer than 1961-1990 was.

The problematic detail is that the 0.71C figure relates to the past three decades, indicating an accelerated warming trend of 0.24C per decade.  The figures do show a slight reduction in the rate of warming since the 1990s but my suspicion is that this is because the 1990s were characterised by an anomalously high frequency of warm synoptic setups in both winter and summer (in particular "westerly" winters and anticyclonic summers), whereas the subsequent two decades were not.

Edited by Thundery wintry showers
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Posted
  • Location: Ossett, West Yorkshire
  • Location: Ossett, West Yorkshire
7 hours ago, Thundery wintry showers said:

It doesn't work that way because Roger's analysis is comparing decadal shifts in 30-year means, but interestingly the 60-year trend could be derived by comparing 1991-2020 with 1931-1960, in which case you'd get slightly less than 0.71C of warming (the figures point to nearer 0.6C, or a mean trend of 0.1C per decade).  In common with the Northern Hemisphere as a whole, England saw a relatively warm phase around the 1940s, leading to 1931-1960 being slightly warmer than 1961-1990 was.

The problematic detail is that the 0.71C figure relates to the past three decades, indicating an accelerated warming trend of 0.24C per decade.  The figures do show a slight reduction in the rate of warming since the 1990s but my suspicion is that this is because the 1990s were characterised by an anomalously high frequency of warm synoptic setups in both winter and summer (in particular "westerly" winters and anticyclonic summers), whereas the subsequent two decades were not.

The 2000s did have a high number of warm synoptic setups in winter; Feb 2000, Jan and Feb 2002, winter 2006-07, winter 2007-08 to name them.  Jan 2005 also was mostly SW'ly, but then Feb 2005 saw a pattern change to a colder pattern.  Winter 2002-03 also had a fair amount of blocking to the NE, although it never quite came together to bring notable cold.  Winter 2005-06 saw generally HP too far east to bring a notable cold spell.  In the 2010s, winter 2013-14 had a high number of warm synoptic setups and definitely Dec 2015.  Feb 2019 saw a similar warm synoptic setup to Feb 1998.  I think that in the 1990s it was more the summers that had more anticyclonic spells with winds from the warm continent, whereas in the 2000s and 2010s I can only think of summer 2003, July 2006, July 2013 and June / July 2018 that saw a particularly warm synoptic pattern.

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Posted
  • Location: Manchester
  • Location: Manchester
On 31/07/2019 at 22:03, B87 said:

Here are the averages from London for 1989-2018, so the 1991-2020 averages should be very similar.

image.png.dd48bf52686533a7761c8032d1934a

Slightly warmer, wetter and cloudier than the 1981-2010 averages.

Noticeably warmer than the 1981-2010 average in some months. The winter averages are remarkably high- there can't be many places at London's latitude with such mild winters anywhere globally?

Only a very tiny reduction in sunshine- 14 hours annually? That's the equivalent of one clear summer's day! There have been a number of cloudy Augusts in the last 10/15 years which may account for that to a degree.

That July average is now very close to 24C, which is higher than some cities on the continent. Very similar to Munich, Warsaw, Prague and Berlin and warmer than Lille and Brussels.

Edited by Scorcher
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Posted
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield
  • Weather Preferences: Any Extreme
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield

Jan   Feb  Mar  Apr  May  Jun   Jul   Aug   Sep   Oct   Nov  Dec

4.2   4.3   6.3   8.4  11.8  14.5 16.7 16.3  13.7  10.2   6.8  4.6

4.5   4.7   6.5   8.8  11.9  14.7 16.9  16.4 13.9  10.4  7.0   4.8

Jan can drop a little if we don't get a record breaker. April is the biggest increase interestingly.

 

Edited by The PIT
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Posted
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield
  • Weather Preferences: Any Extreme
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield

Out of interest anybody know what the predicted increase was ??

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Posted
  • Location: Hounslow, London
  • Weather Preferences: Csa/Csb
  • Location: Hounslow, London
On 15/01/2020 at 17:20, Scorcher said:

Noticeably warmer than the 1981-2010 average in some months. The winter averages are remarkably high- there can't be many places at London's latitude with such mild winters anywhere globally?

Only a very tiny reduction in sunshine- 14 hours annually? That's the equivalent of one clear summer's day! There have been a number of cloudy Augusts in the last 10/15 years which may account for that to a degree.

That July average is now very close to 24C, which is higher than some cities on the continent. Very similar to Munich, Warsaw, Prague and Berlin and warmer than Lille and Brussels.

The means are up by 0.4c in most months, from the 81-10 averages. London is the warmest place on Earth, north of 50N.

Mar-May have all seen slight sun increases, while the rest have seen slight decreases (apart from August which has dramatically decreased).

Munich is at high elevation, and London has had warmer summers than Brussels or Lille for as long as I can remember.

From my calculations, I believe July's LTA will end up at 23.9c if July 2020 averages between 22.4c and 25.3c. Outside of that range it will either be 23.8c or 24.0c.

Edited by B87
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  • 3 weeks later...
Posted
  • Location: Hounslow, London
  • Weather Preferences: Csa/Csb
  • Location: Hounslow, London

I have compiled this wiki-style table for London's 1991-2020 averages. It will be updates as the year progresses.

Annual mean +0.4c, sunshine -40 hours, rainfall +10mm, rain days +6, so far.

iPlHptX.png

Edited by B87
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