Annual CET

[Methuselah]

41 minutes ago, Earthshine said:

If so much energy stored in the Mediterranean (SST in some places 30°C+) would help keep continental Europe warm well into autumn.  How much influence we get is anyone's guess, however autumn 2006 stayed warm after that exceptional summer.

Aye, ES: the Med (along with NW Africa, Spain & Portugal have been warm for a few years now): mixing between very cold Siberian air and warmer air of Mediterranean origin has always been a problem for UK snow chasers -- snowfall at 7C and 100% RH never happens. And, with things the way they are now, even those conditions will become a thing of the past!

But, snowfall aside, it's the summertime trend that's worrying me most: 2018,19,20,21 and 22 have each seen spells of 'super-hot' weather -- FIVE consecutive summers! But, unfortunately, too many peeps still have their heads in the sand?

Edited August 7, 2022 by Ed Stone

[LetItSnow!]

3 hours ago, Ed Stone said:

Aye, ES: the Med (along with NW Africa, Spain & Portugal have been warm for a few years now): mixing between very cold Siberian air and warmer air of Mediterranean origin has always been a problem for UK snow chasers -- snowfall at 7C and 100% RH never happens. And, with things the way they are now, even those conditions will become a thing of the past!

But, snowfall aside, it's the summertime trend that's worrying me most: 2018,19,20,21 and 22 have each seen spells of 'super-hot' weather -- FIVE consecutive summers! But, unfortunately, too many peeps still have their heads in the sand?

Indeed - us in the south probably underestimate the summer of 2021. Down here there was only a short spell of 32degC weather in July and August brought absolutely no warm and settled weather really - but up north and across Ireland it was a very warm summer. The temperatures recorded in NI may seem unexceptional to us, but it was a notable event. I think Scotland had one of its warmest Julys on record in 2021? It was a very strange summer. 

 

Back to the topic of conversation - If blocked weather patterns we're seeing now persist into the autumn, it could turn quite chilly. October 2003 is a good example of a cold month in an otherwise warm year. Or it could do a 2006 like has been said, though 2006 stayed pretty cold to average up until May and then switched. If the anomalies of May 2006 through April 2007 had coincided with a calendar year then it would blow 2014 out the park. It had a C.E.T. of something crazy like 11.63.

[SqueakheartLW]

Top 10 hottest summers by CET Mean vs Annual CET Mean positions for these years as a whole

SUMMERS                                                             ANNUAL
12?             2022      16.719
If 16.719 ends up the summer CET mean

Position    Year       Summer CET Mean            Position    Year      Annual CET Mean
1                 1976     17.864                                  2                 2006    10.863
2                 2003     17.348                                  5                 2018    10.679
3                 2018     17.298                                  12              1995     10.543
4                 1995     17.221                                  13              2003     10.542
5                 2006     17.171                                  30              1976     10.101
6                 1933     17.029                                  32              1983     10.091
7                 1983     17.010                                  36              1975     10.037
8                 1947     16.973                                  46              1933     9.861
9                 1899     16.906                                  57              1899     9.710
10               1975     16.875                                  60              1947     9.646

One thing that is noticeable is how the years with the hottest summers are generally not the years that end up overall the warmest on the CET Annual mean record. Maybe that could partly be the reason that summer 2022 isn't looking likely to topple 1976 but maybe could end in the 17C range if we stay hot enough.

Now time for a reverse comparison. The top 10 years on the Annual CET Mean record vs where these years summers ranked overall.

ANNUAL                                                             SUMMERS

1?              2022     11.083
If current 11.083 were to end up final annual CET Mean

Position    Year     Annual CET Mean            Position    Year     Summer CET Mean
1                2014    10.948                                3                2018    17.298
2                2006    10.863                                5                2006    17.171
3                2020    10.752                                16             1949     16.511
4                2011    10.715                                27             2017     16.157
5                2018    10.679                                28             1990     16.135
6                1999    10.660                                30             2020     16.102
7                1990    10.655                                36             2014     15.900
8                1949    10.642                                45             1999     15.809
9                2002    10.621                                55             2002     15.676
10              2017    10.584                               106            2011     14.781

There's an even bigger difference here between the top 10 warmest years on the annual CET mean record vs where their respective summers stood. 2006 and 2018 are the closest in terms of positions of their years as a whole and their summers (Annual 2nd for 2006 and 5th for it's summer as well as annual 5th for 2018 vs 3rd for it's summer)

Probably the most noticeable differences are with 2014 and 2011. 2014 is the warmest on record for the year as a whole yet summer 2014 is only 36th warmest. 2011 is the biggest difference by far. 2011 overall is 4th warmest year on the CET record yet summer 2011 is in a distant 106th on the record of 144 years featured (1878 to 2021)

What the above comparisons show is that in order to have a very warm year you don't have to have a hot summer to achieve this and likewise a hot summer doesn't necessarily mean a warm year overall.

[SqueakheartLW]

A whole month after I did one of these so thought it was time I did another assessment of where we stand with the rolling CET mean for 2022 vs the years 1878 to 2021. These have been based and for this year will be based on the legacy series as I simply haven't got around to getting the new data series yet.

In my previous update 2022 had moved up to top spot after the record breaking hot days in July that pushed us up from 4th position to top spot but after a whole month since how do we stack up now and with a number of very warm or hot spells I had my suspicions we would still be top and so it proved when I checked.

I have included the top 3, bottom 3 and all years since 2010 on the list as I usually do

As can be seen 2022 still stands top and in fact compared with a month ago the margin it has is bigger than it was back on 20th July 2022.

20th July 2022 comparison

Then it was a rolling mean of 10.346C (+0.050C ahead of 2007) at that stage and crucially (+0.058C) ahead of 2014 that ended up the top year on the record to date.

At this point if the margin was maintained and we matched 2014 like for like to the end of the year we would have ended up with a CET Mean of 11.006C so a first official 11C CET mean year on the record based on 20th July's margin to 2014 at that stage.

20th August 2022 comparison (Current)

How does the rolling mean stack up now. On the latest figure for 20th August the rolling CET Mean stands at a high 11.485C (+0.251C ahead of 2020) but crucially the gap to the warmest year on the record 2014 has increased by quite a margin to +0.338C which if maintained to the end of the year would give us a final rolling CET Mean for 2022 of 11.286C which would be an easy 11C year even if finalised data corrects downwards somewhat.

No wonder we are pulling clear of 2014 at present however since August 2014 was a rather cool month at 14.995C vs the current August 2022 provisional CET up to 20th of 19.375C

Monthly CET's to watch out for through September to December 2022

We only really need to match 2014 now to beat the record so the following monthly CET's based on legacy data will be enough. However I have included what was the warmest monthly CET's on the record too as well as the year to show how much warmer we could go during the rest of the year.

2022 projected assumes first we match 2014 exactly date by date from 21st August 2022 to 31st December 2022. The 2022 warmest column is more experimental to see where the CET Mean could end up by the end of the year if we match the daily CET means of August 1995 (For 21st to 31st August) then match September 2006, October 2001, November 1994 and finally December 2015 for the rest of the year.

                          2014                2022 Projected (2014)               Warmest                    2022 Projected (Warmest)   

August             14.995C           17.455C (2014 21st to 31st)      19.174C (1995)         18.671C (1995 21st to 31st)

September      15.083C           15.083C                                        16.833C (2006)         16.833C

October           12.477C           12.477C                                        13.329C (2001)         13.329C

November       8.577C             8.577C                                          10.083C (1994)         10.083C

December       5.148C             5.148C                                           9.674C (2015)           9.674C

FINAL              10.948C           11.162C (+0.214C above)                                             11.990C (+1.042C above)  

[LetItSnow!]

A very crude guide to where we could be ending up in this exceptional year.

If the rest of the year from September records near-average temperatures (based on 1991-2020) then we're looking at around 10.9-11.0.

If the rest of the year remains warm with anomalies around a degree above average, we could be looking around 11.2-11.4(!).

If the rest of the year cools down with anomalies around a degree below average then we could be looking around 10.5-10.7.

Even if the rest of the year recorded record-breaking cold weather (which is probably a one in a million chance, if that), we would still be around 9.3.

It is very likely we will meet or fall slightly above or below the record of 2014 (10.95). However, remarkably, it is now quite possible we could exceed 11degC and not just rounded up, but fully surpass it. We even have a decent chance of the mid-11s, something only May 2006 to April 2007 managed. We most likely won't beat that, but in the unlikely chance that record warmth persisted until December, we could beat it and finish in the upper 11s. I don't think this will happen in my opinion. I think 5/06-4/07 will remain the hottest ever 12 months ever, but in terms of calendar year, I think 2022 will take it and take second overall in any 12 months.

I think it's been a year that's felt more exceptional than 2014 in many ways. 2014 achieved its record through persisted mildness and rarely any records were achieved (except Halloween). For example, the hottest temperature of 2014 was a very tame 32degC. 2022 on the other hand has been peppered with records tumbling here and there. We saw a very fitting start to the year with record warmth on New Year's Day, then exceptionally mild in February and March. April was more tame but then May broke the minima warmth record. July smashed the all time temperature record and then mid-July to mid-August recorded a C.E.T. average of over 20degC and overall while August hasn't seen exceptionally hot weather, it's been prolonged warmth and heat that has kept it high. 

A part of me thinks that it's got to end sometime soon. For example, when the summer of 2007 came on the back of such record warmth, it ushered in a general much cooler period after. One could argue that the climate was a lot different then, but on a country scale I don't think it's changed much since 1988 - although heat spikes are one exception. Also, a lot of the current weather patterns that have persisted through the summer will eventually bring chilly weather as we move through into the autumn. An anticyclonic easterly come October will start to be quite cold, and dry ground and clear skies means this autumn has a greater chance of cold nights. However, that all rides on the idea that current weather patterns will continue in the same vein. We could switch back to cyclonic weather into the autumn and that could provide some very mild weather as in the case of autumn 2006. I will be very interested in seeing where 2022 ends up and whether 2023 will continue in the same vein or swing back to cooler like 2021/2008 etc.

...How long ago does the chilly first-half to 2021 feel now!? 

[Maz]

After the August CET update the met office site says that if temperatures are 0.53c above average Sept - Dec, the annual CET will be the highest recorded.

With warm start to September and the well above average Atlantic sea surface anomalies, that must be very probable now I would think.

[Don]

54 minutes ago, Maz said:

After the August CET update the met office site says that if temperatures are 0.53c above average Sept - Dec, the annual CET will be the highest recorded.

With warm start to September and the well above average Atlantic sea surface anomalies, that must be very probable now I would think.

Yep, odds on!

[summer blizzard]

Rolling CET for Sep-Aug is 11.26C. 

[LetItSnow!]

With September 2022 likely to finish at 14.5, a near-average Oct-Dec will bring us around 10.9-11.0, a generally mild (+1.0) end would bring us to 11.2-11.3 (!), a return to exceptionally above average would bring us to around 11.4-11.5(!!!), or if recent conditions are to show that 2022 has finally ran out of steam, then a rather cool couple of months would bring us to. 10.7-10.8.

 

Virtually no chance of escaping a top 5 warmest year with a top 3 most certain, and quite likely #1. The overall record of May 2006-April 2007 (11.6) looks mostly safe though. Warmest calendar year and second warmest of any 12 months we reckon?

[Don]

6 hours ago, LetItSnow! said:

 Warmest calendar year and second warmest of any 12 months we reckon?

I would say that's a fairly safe bet yes.

[summer blizzard]

Rolling CET fell to 11.13C for the Oct-Sep period. 

[SqueakheartLW]

The only year we need to focus on now is 2014. Just match 2014 for the remainder of the year and the record is broken.

Early on in September it looked like we were going to easily beat September 2014's CET of 15.08C as we trended ahead of 2014 for most of the month but then September 2022 started to fall back until on the 26th the CET values were both exactly the same at 15.04C.

By month's end 2014 was at 15.08C whilst 2022 has come in at 14.45C.

Where does this place us relative to the eventual top 10 years on the CET record between 1878 and 2021

Position     Date                Rolling CET

1                 30/09/2022    12.055
2                 30/09/2014    11.693
3                 30/09/2020    11.678
4                 30/09/1990    11.652
6                 30/09/1999    11.606
9                 30/09/1949    11.514
10               30/09/2002    11.475
11               30/09/2017    11.462
13               30/09/2006    11.423
16               30/09/2018    11.377
26               30/09/2011    11.165

As you can see we are still clearly out top despite the cooler September compared with other months this year although the September 2022 value of 14.45C which turned out to be over 0.5C cooler than 2014 has pulled 2022 back down slightly towards the 2014 rolling value.

The gap last time I looked at rolling CET values on 26/08/2022 was 0.459C above 2014 but 2014 was down in 5th position at this stage and the 2nd placed year under the top provisional 2022 value at that time was in fact 2020 but that year fell away in September.

After September 2022 the rolling CET came in at 12.055C which in itself is an impressive rolling value to be at for this stage of the year and is now 0.362C above 2014 which is a slight reduction in the gap and after the relatively warm September of 2014 that pushed 2014 above all the other years.

October 2022 vs October 2014

Where are we going to be placed relative to 2014 in this month.

The value to be looking out for is 12.48C by the end of October 2022. If we equal or exceed this then the record is still game on although with our slender lead over 2014 at this stage we could get away with falling a small amount short of 2014 and still be on course to beat the annual CET record from 2014.

2014 has got off to a big head start already this October if the provisional data turns out to be correct.

Date    CET 2014    Rolling 2014            CET 2022    Rolling 2022
1st       15.60          15.60                        14.00           14.00
2nd     13.60           14.60                        13.50          13.75
3rd      15.20           14.80                        11.40          12.97

2022 is already -1.83 behind 2014 after the first 3 days of October although it is early days. If there's any chance of beating 2014's record then this isn't the start you would want to be seeing.

After all the record warmth in 2022 to end up missing out on the record or an 11C CET year would really disguise how warm the year has really been.

Edited October 4, 2022 by SqueakheartLW

[summer blizzard]

Rolling CET increased to 11.2C for the Nov-Oct period. 

[kold weather]

A very mild October has made it more likely again to break the record. We can now afford to have a modestly below average last 50 days and still end up having a record breaking year.

With that being said, we are well overdue a below average month...

[Don]

17 minutes ago, kold weather said:

A very mild October has made it more likely again to break the record. We can now afford to have a modestly below average last 50 days and still end up having a record breaking year.

With that being said, we are well overdue a below average month...

We haven't even had a month below the 91-20 average this year!!

[kold weather]

15 minutes ago, Don said:

We haven't even had a month below the 91-20 average this year!!

At the moment the daily required average needs to be 0.49c below the 61-90 average for it not to be a record.

We've been struggling to get a week below that average in recent times, a period of 55 days roughly being 0.5c below the 61-90 feels highly unlikely now, and obviously as time goes by that figure is only going to grow.

[richie3846]

51 minutes ago, Don said:

We haven't even had a month below the 91-20 average this year!!

I believe it's 18 months now! Or is that the 61 to 90?

Edited November 6, 2022 by richie3846

[reef]

20 hours ago, richie3846 said:

I believe it's 18 months now! Or is that the 61 to 90?

Yep, the last month below the 1961-1990 average was May 2021.

January 2022 was equal to the 1991-2020 average so the last below average month on that measure was November 2021, though that was only 0.1C below the mean.

Edited November 7, 2022 by reef

[Roger J Smith]

If this month ends up near 9 C then only the coldest Decembers could prevent this from being the warmest year. We have a 3.1 deg surplus Jan to Oct over 2014, which finished 8.5 5.1, so from 9.0 and a 3.6 surplus, we just need to finish 3.5 behind Dec 2014 at 1.6 C. If we finished 10.0 that would change to 0.6. 

[kold weather]

17 hours ago, Roger J Smith said:

If this month ends up near 9 C then only the coldest Decembers could prevent this from being the warmest year. We have a 3.1 deg surplus Jan to Oct over 2014, which finished 8.5 5.1, so from 9.0 and a 3.6 surplus, we just need to finish 3.5 behind Dec 2014 at 1.6 C. If we finished 10.0 that would change to 0.6. 

Even if November got down to 8c it would still take December come in at 2.6, something only done twice in the last 30 years (95 and obviously 2010).

[Roger J Smith]

Not sure if v2.0 annual means are simply averages of the twelve monthly values, weighted averages or even daily averages, but if the first of those, the 11.0 of 2014 is actually 10.95. That means if 2022 moves ahead but by less than an accumulated surplus of 1.2 C, it will round off to same value. Just saying. If it's weighted then might need less to move ahead in one decimal. 

Edited November 10, 2022 by Roger J Smith

[kold weather]

Warmest year ever now looking highly likely (like 99% IMO) now unless we get something fairly exceptional in December.

Required temperatures to be below 2014 is now 1.7c below the 61-90 until the end of the year.

To put that into context, the last month to average that sort of anomaly was March 2013. Even the relatively cold April 2021 wouldn't do the trick.

The next week looks much closer to average, but that required temperature will probably carry on growing a little further yet as there isn't that much of proper cold at the level to match that temperature anomaly required other than maybe the odd day here and there. Pattern is too mobile still. 

Edited November 18, 2022 by kold weather

[Nick L]

Yep, warmest year on record pretty much nailed on, and it could be by some distance too.

[SqueakheartLW]

Where will the final annual 2022 mean CET finish based on what December 2022 could bring

Current provisional rolling annual 2022 CET mean after November 2022 is

2022 Provisional at this stage = 11.865C (+0.379C above 2014)
2014 at the same stage = 11.486C

2014's record breaking mean (legacy) is 10.948C

How does the provisional 2022 annual mean CET end if ....

CATEGORY                                                               Pred Annual CET Mean     Anomaly to 2014 (Legacy)
We get a December 2015 (9.67C)                        11.679C                                +0.731C (Record smashed)
We get a December 2014 (5.15C)                        11.294C                                +0.346C
We get a December 71-00 mean (5.06C)            11.287C                                +0.339C
We get a December 91-20 mean (4.97C)            11.279C                                +0.331C
We get a December 61-90 mean (4.65C)            11.252C                                +0.304C
We get a December 81-10 mean (4.63C)            11.250C                                +0.302C
We get a 4.50C CET mean December 2022        11.239C                                +0.291C
We get a 4.00C CET mean December 2022        11.197C                                +0.249C
We get a 3.50C CET mean December 2022        11.154C                               +0.206C
We get a 3.00C CET mean December 2022        11.112C                                +0.164C
We get a 2.50C CET mean December 2022        11.069C                                +0.121C
We get a 2.00C CET mean December 2022        11.027C                                +0.079C
We get a 1.50C CET mean December 2022        10.984C                                +0.036C
Match 2014 Annual Legacy CET = (1.07C)           10.948C                               +0.000C (Record equalled)
December 1879 repeat (0.700C)                          10.916C                                -0.032C
December 1981 repeat (0.297C)                          10.882C                                -0.066C
December 1878 repeat (-0.303C)                         10.831C                                -0.117C
December 2010 repeat (-0.694C)                         10.798C                                -0.150C
December 1890 repeat (-0.800C)                         10.789C                                -0.159C

Basically we need a December CET of 1.45C to equal the new 2014 annual CET mean of 10.980C or 1.07C to equal the existing legacy 2014 annual CET mean of 10.948C

Only December 1879, 1981, 1878, 2010 and 1890 on my records between 1878 and 2021 can prevent the record from 2014 from getting broken.

[Earthshine]

1 hour ago, SqueakheartLW said:

Where will the final annual 2022 mean CET finish based on what December 2022 could bring

Current provisional rolling annual 2022 CET mean after November 2022 is

2022 Provisional at this stage = 11.865C (+0.379C above 2014)
2014 at the same stage = 11.486C

2014's record breaking mean (legacy) is 10.948C

How does the provisional 2022 annual mean CET end if ....

CATEGORY                                                               Pred Annual CET Mean     Anomaly to 2014 (Legacy)
We get a December 2015 (9.67C)                        11.679C                                +0.731C (Record smashed)
We get a December 2014 (5.15C)                        11.294C                                +0.346C
We get a December 71-00 mean (5.06C)            11.287C                                +0.339C
We get a December 91-20 mean (4.97C)            11.279C                                +0.331C
We get a December 61-90 mean (4.65C)            11.252C                                +0.304C
We get a December 81-10 mean (4.63C)            11.250C                                +0.302C
We get a 4.50C CET mean December 2022        11.239C                                +0.291C
We get a 4.00C CET mean December 2022        11.197C                                +0.249C
We get a 3.50C CET mean December 2022        11.154C                               +0.206C
We get a 3.00C CET mean December 2022        11.112C                                +0.164C
We get a 2.50C CET mean December 2022        11.069C                                +0.121C
We get a 2.00C CET mean December 2022        11.027C                                +0.079C
We get a 1.50C CET mean December 2022        10.984C                                +0.036C
Match 2014 Annual Legacy CET = (1.07C)           10.948C                               +0.000C (Record equalled)
December 1879 repeat (0.700C)                          10.916C                                -0.032C
December 1981 repeat (0.297C)                          10.882C                                -0.066C
December 1878 repeat (-0.303C)                         10.831C                                -0.117C
December 2010 repeat (-0.694C)                         10.798C                                -0.150C
December 1890 repeat (-0.800C)                         10.789C                                -0.159C

Basically we need a December CET of 1.45C to equal the new 2014 annual CET mean of 10.980C or 1.07C to equal the existing legacy 2014 annual CET mean of 10.948C

Only December 1879, 1981, 1878, 2010 and 1890 on my records between 1878 and 2021 can prevent the record from 2014 from getting broken.

Even more stark is the maximum CET record.  We'd need a December with a maximum CET of around 7°C below normal (so essentially the MAX mean temperature for the month is around ~0°C).  Even December didn't get that cold, with the maximum CET a comparatively balmy 2.4°C