Annual CET

[Don]

Was 2023 the first year not to have one month come in with an average below 61-90?

[reef]

6 minutes ago, Don said:

Was 2023 the first year not to have one month come in with an average below 61-90?

Yes it was I believe.  I think without December 2022 it would have been 31 consecutive months, the last below average before being May 2021.

With regards to 2024,  there's a good chance it will also be 11+C as we're in an El Nino year. That three 11C years on the trot could certainly happen.

Edited January 2 by reef

[LetItSnow!]

1 hour ago, reef said:

Yes it was I believe.  I think without December 2022 it would have been 31 consecutive months, the last below average before being May 2021.

With regards to 2024,  there's a good chance it will also be 11+C as we're in an El Nino year. That three 11C years on the trot could certainly happen.

I still think three would be pushing it a little and I don’t see it happening myself, but I never saw 2023 happening either. Are El Niño years always more anomalously warm for us? They tend to have very mild spells in the winter but 1998 and 2016, while warm years, were more modest than other years we’ve had in the past thirty years in terms of annual temperatures. Also if we’re heading into a chilly January (verdict’s still out) that could put pay to that idea. 

[reef]

14 minutes ago, LetItSnow! said:

I still think three would be pushing it a little and I don’t see it happening myself, but I never saw 2023 happening either. Are El Niño years always more anomalously warm for us? They tend to have very mild spells in the winter but 1998 and 2016, while warm years, were more modest than other years we’ve had in the past thirty years in terms of annual temperatures. Also if we’re heading into a chilly January (verdict’s still out) that could put pay to that idea. 

Global temperatures tend to be warmer in El Nino years, so it increases the chance we'll be warm. Its not always the case though.

[summer blizzard]

Given the change in outlook, do we have any rolling annual precipitation comparisons.

[kold weather]

Whilst January was fairly modest, February near record breaking mildness has probably put a 11c CET at least into contention again, especially if March also comes in above normal.

We will lose ground on the rolling EWP as Mar was exceptionally wet last year, and whilst it does look wet on the models, I'm not seeing anything yet to that kind of level, but May-June was a fairly dry combo so if either of those months come in considerably wet we'd have a high chance of breaking the all time rolling 12 month EWP.

Edited March 11 by kold weather

[WYorksWeather]

If March were to finish roughly where it is now (7.9C as of the 19th March), then the average anomaly will be around 2.3C for the first three months. Worth noting that is a higher figure than either of 2023 or 2022, both of which turned out to be 11C CET years.

 

[Relativistic]

First 12°C year anyone?

[BlueSkies_do_I_see]

 Relativistic It's an interesting proposition. Could you give me a theoretical CET 12C year,month by month keeping within CET monthly records, preferably mainly 1C below.

Edited April 2 by BlueSkies_do_I_see

[rwtwm]

 BlueSkies_do_I_see I'm not certain I've done this right, but I think if you round each month's record down to the nearest integer, the mean across that hypothetical year would be around 12.6c.

I'd be happy for someone to check my work on this. Also worth noting that neither January or March reached the required value, so we'd probably need to hit at least one record to make 12c, even from this very mild start.

[Don]

 Relativistic Only a matter of time whether it's 2024 or not......

[LetItSnow!]

Considering the warmest 12 month period is 11.6 and that was set back in 2006/2007, with extra warming in the atmosphere it is no longer inconceivable that a 12C CET year is possible. 

For interests sake only, I averaged the record warmest CET months for each month of the year and added about about half a degree to the old records (that’s being modest perhaps) and it gave an annual CET of 13.58! It would take an absolute unprecedented extreme to see this and I don’t think we will record that any time soon, but in a high emissions scenario it may not be out of the question for that to occur in like 2100 or 2150 or something. 

[BlueSkies_do_I_see]

The below would give an Annual CET of 12C

Month     Record     2024 Projection

January     7.5 °C   4.7C   (actual)

February  7.9 °C   7.8C  (actual)

March       9.2 °C    8.1C  (actual)

April       11.8 °C     10C

May        15.1 °C      14C

June       18.2 °C      17C

July         19.8 °C      18C

Aug       19.1 °C       18C

Sept      17.0 °C       16C

Oct        13.3 °C      12.5C

Nov        9.9 °C        9C

Dec        9.6 °C        9C

That will be achieved in my lifetime, I think.

Edited April 2 by BlueSkies_do_I_see

[summer blizzard]

Rolling CET for April-March rose to 11.23C. 

[WYorksWeather]

 BlueSkies_do_I_see Your April projection already looks like it could be too low. Who knows, maybe a lot sooner within your lifetime than you thought!

In all seriousness, I still don't expect 2024 to make 12C when we've not even seen an 11.5C year before, that'd just be so ridiculous it frankly stretches credulity. But I have to admit, the current numbers mean that it's not totally implausible if everything falls right for the rest of the year. I'd give it probably odds of about 5% or less though. But a third 11C in a row is probably quite likely. If we get through the first half of the year with similar warm anomalies it'd start to become odds on almost - it would then take one heck of a cool second half of the year relative to what we've seen recently to prevent it.

If we had a 2C anomaly at the end of June, which would already represent a drop from where we are now, we'd then need an anomaly of only around 1C on 1961-1990 for the rest of the year. The last period to be cooler than that was the second half of 2020 and first half of 2021. Of course, nothing to say it can't happen, but you have to say that if that were the situation - 2C anomaly at the end of June, which doesn't look at all implausible, you would probably bet against the latter half of the year only managing 1C above 1961-1990 or less.

[BlueSkies_do_I_see]

 WYorksWeather The reason I make these bold predictions about heat records is, to use gambling parlance , we are playing with a loaded dice.

I don't expect to reach 12C either this year. The regime we are in right now with all of these wet and cloudy nights  leads to very mild 9am/9pm temperatures between Oct-Apr, but we need to lose the low pressure systems after that to get the high CET values.

You can see the high pressure starting to build now to our south and if the jet stream migrates northward, we are at some point going to tap into the heat.

I spent the afternoon at the allotment today and it amazed me to see how quickly the grass dried in the warm, windy conditions.

We could do with more days like today. I'm not a great fan of wind, but I'm even less a fan of muddy, boggy ground.

I will be surprised if we don't get another 11C CET year after the start we have had. It would take a brave person to bet against it now. As your analysis shows, if the mild continues much longer, it becomes odds on.

Edited April 6 by BlueSkies_do_I_see

[WYorksWeather]

 BlueSkies_do_I_see Yeah I don't think it's a bold prediction that a 12C CET year will happen by mid-century. Possibly even before that.

And yes it is crazy how such an unimpressive set of surface conditions could still deliver 20C, just on the strength of the warm air aloft. Very breezy, no real direct southerly blast, and lots of cloud to limit heating. And yet we still got to 20C in early April.

[Don]

2 hours ago, BlueSkies_do_I_see said:

will be surprised if we don't get another 11C CET year after the start we have had. It would take a brave person to bet against it now. As your analysis shows, if the mild continues much longer, it becomes odds on.

I'm thinking a third 11C CET year on the trot is getting more and more likely and could well surpass 2022 and 2023, making it the warmest year on record!

[summer blizzard]

Excited though we are getting, years like 2007 and 2020 did go off the boil so I think we should avoid being too bullish.

[WYorksWeather]

Certainly a long way to go this year. December 2022 came out of nowhere with the below average CET - that could still happen this year at some stage and would likely scupper any record attempt unless another month contributes an insane anomaly to counteract it.

It's probably not that likely that we get another month like that soon, and the probability of a month ending up 1C below 1961-1990 is probably something like 5% or less these days, but it will happen again at some stage.

[reef]

An anomaly over the remaining 9 months of +1.9-2.0C would be required to hit 12C for the year. It doesn't sound ridiculous until you lay out the months with a uniform anomaly:

April: 11.0C
May: 13.9C
June: 16.6C
July: 18.8C
August: 18.6C
September: 16.2C
October: 12.8C
November: 9.3C
December 6.9C

That would be an 11.0C Spring (0.7C above current record), 18.0C summer (0.3C above) and 12.8C Autumn (0.2C above). At this point you realise the mountain we'd have to climb. If that did happen we'd be in real trouble!

[BlueSkies_do_I_see]

 reef Some of those targets look more achievable than others. 13.9C or higher in May for example, has only ever been achieved twice:  1848 (13.9C) and 1833 (15.1C).

If we even approach the 13.9C figure next month, I will start to believe an annual 11.5C is possible.

Even the sun soaked May 2018 only checked out at 13.3C.

Edited April 7 by BlueSkies_do_I_see

[SqueakheartLW]

What is of particular interest for this year is how warm the start has been and you'd think we are top at this stage but one year had a warmer start than this one and that year was 1990. This is based on years from 1878 onwards when daily mins, maxes and means are all available.

Below I have the 6th April rolling annual mean CET's

6th April Rolling Annual Mean CET

Pos     Year     6th Apr Rolling Mean          Final Finishing Pos          Final Rolling Mean
1         1990     7.266                                     9                                         10.655
2         2024     7.137                                     ???                                      ???
6         2014     6.804                                     3                                         10.948
10       2020     6.637                                     5                                         10.752
11       2022     6.538                                     1                                         11.149
12       1999     6.450                                     8                                         10.660
18       2023     6.330                                     2                                         11.101
32       2011     5.944                                     6                                         10.715
40      1949      5.700                                     10                                       10.642
88      2018      4.613                                     7                                         10.679
97      2006      4.493                                     4                                         10.863

1990 of course did go on to finish in our current top 10 warmest years on record but slipped down the order compared with some other top 10 years

What would be of interest would be if from today forwards we saw 2006 values from 7th April to 31st December 2024 (The year that has most to gain of the eventual top 10 from this point forwards) the provisional annual CET at the end of 2024 would be .....

11.546C

Shows what could be possible this year with a new annual record set that would smash 2022 by a decent margin of +0.397C

[WYorksWeather]

 reef I think if you weighted the anomalies slightly by season and how readily we seem to achieve them, it'd probably be slightly more achievable.

If I start with your figures (reposted below for convenience):

Quote

April: 11.0C
May: 13.9C
June: 16.6C
July: 18.8C
August: 18.6C
September: 16.2C
October: 12.8C
November: 9.3C
December 6.9C

I would probably say making summer fall short of record-breaking, then adding more of the extremes into autumn and December is probably a more likely scenario for how we would eventually hit 12C. I don't expect that we'll hit it this year though, or indeed before 2030, though I hope I don't regret the latter prediction. I would probably go with something like the following (with changes from your numbers in brackets):

April: 11.0 (0)

May: 12.9 (-1.0)

June: 16.1 (-0.5)

July: 18.3 (-0.5)

August: 18.1 (-0.5)

September: 16.7 (+0.5)

October: 13.8 (+0.5)

November: 9.8 (+0.5)

December: 7.9 (+1.0)

Summary

This of course balances out with the sum of my edits equalling zero - I used round adjustments to make it easier for me to do. In terms of reasoning - a warm May seems tough to achieve lately, and a summer as consistently hot as your equal anomaly method is also tough - we always seem to have one slightly worse month that would scupper it, unless we had something unprecedented like a 20C+ July or August.

By contrast, our autumn and early winter temperatures are just breaking records all the time, so I thought why not make September near record-breaking, smash the October record, make November close to record-breaking, and then a pretty extreme December but still a long way below 2015. I'd even be half-tempted to say you throw another half a degree or even a full degree on December and then you can make the autumn a bit less ridiculous, if anything. It'd still be short of December 2015, which shows how high the ceiling is.

From where we are, it's a very tall order. By 2030 I think is very unlikely. By 2040 probably fairly evenly balanced, though I'd probably reserve judgement until we see how far we push the ceiling by 2030. But by 2050 I think it will have happened with near certainty.

Key uncertainties I think on the timeframe are how far we can push the numbers for May and June - they both have very old records that haven't had a close shave in recent years. If that changes, especially if it's a December 2015 type month and they get absolutely smashed, well then all bets are off, and a 12C year could happen a lot sooner.

Back to this year - if we get to the end of June and the anomaly looks similar to now, I'd say we're odds on for another 11C year. Never a certainty after only half the year, but it would look quite likely at that stage IMO.