October 2023 C.E.T. and EWP contests

[Roger J Smith]

On 08/10/2023 at 03:27, Stationary Front said:

Will the first half of this Autumn be the warmest on record (CET)?

If we take 1-15 Oct as completion of it, top 20 at present including necessary Oct 2023 running mean on 15 Oct to tie:

Rank ___ CET 1 Sep to 15 Oct ___ 2023 to tie (Oct running mean 1-15)

_ 01 _____ 1949 _ 15.9 ___________ 13.7

_ 02 _____ 2006 _ 15.8 ___________ 13.4

_ 03 _____ 2011 _ 15.0 ___________ 11.0

_ 04 _____ 1959 _ 14.9 ___________ 10.7

_t05 _____ 1825 _ 14.8 ___________ 10.4

_t05 _____ 1865 _ 14.8 ___________ 10.4

_ 07 _____ 2021 _ 14.7 ___________ 10.1

_ 08 _____ 1795 _ 14.6 ____________ 9.8

_t09 _____ 1921 _ 14.5 ____________ 9.5

_t09 _____ 2005 _ 14.5 ____________ 9.5

_t11 _____ 1961 _ 14.4 ____________ 9.2

_t11 _____ 2016 _ 14.4 ____________ 9.2

_ 13 _____ 1985 _ 14.1 ____________ 8.3

_t14 _____ 1869 _ 14.0 ____________ 8.0

_t14 _____ 1947 _ 14.0 ____________ 8.0

_t14 _____ 1969 _ 14.0 ____________ 8.0

_t14 _____ 1995 _ 14.0 ____________ 8.0

(18-20 see below)

Almost a certainty 2023 can beat any even top two in list.

2006 wasn't leader after all, it was 1949 by 0.1.

(18-20 ranks follows, some years around 13.7 to 13.9 not mentioned as 14.0 was cutoff value for list)

2001 was only at 13.7 at 15 October, (13.4 Sep, 14.3 1-15 Oct) ... 1978 was at same average of 13.7, 1898 was at 13.8.

 

[Roger J Smith]

It may be asked already, potential rank of 2023 Sep-Oct average, and top values are:

Rank ____ Year ____ SEP _ OCT ____ mean ______ 2023 to tie

_ 01 _____ 2006 ____16.9 _ 12.9 ____ 14.90 ______ 12.8

_ 02 _____ 2005 ____15.2 _ 13.0 ____ 14.10 ______ 11.2

_t03 _____ 1949 ____16.3 _ 11.7 ____ 14.00 ______ 11.0

_t03 _____ 2021 ____16.0 _ 12.0 ____ 14.00 ______ 11.0

_ 05 _____ 1795 ____16.0 _ 11.7 ____ 13.85 ______ 10.7

_t06 _____ 1731 ____15.3 _ 12.3 ____ 13.80 ______ 10.6

_t06 _____ 2011 ____15.1 _ 12.5 ____ 13.80 ______ 10.6

_ 08 _____ 1959 ____14.9 _ 12.6 ____ 13.75 ______ 10.5

_ 09 _____ 2014 ____15.1 _ 12.3 ____ 13.70 ______ 10.4

_ 10 _____ 2022 ____14.4 _ 12.8 ____ 13.60 ______ 10.2

_ 11 _____ 1969 ____13.9 _ 13.1 ____ 13.50 ______ 10.0

_ 12 _____ 1921 ____14.1 _ 12.8 ____ 13.45 _______ 9.9

_ 13 _____ 2016 ____16.1 _ 10.7 ____ 13.40 _______ 9.8

_ 14 _____ 1729 ____16.6 _ 10.1 ____ 13.35 _______ 9.7

_ 15 _____ 2001 ____13.4 _ 13.2 ____ 13.30 _______ 9.6

_ 16 _____ 1898 ____15.2 _ 11.3 ____ 13.25 _______ 9.5

_t17 _____ 1831 ____13.7 _ 12.7 ____ 13.20 _______ 9.4

_t17 _____ 1968 ____13.9 _ 12.5 ____ 13.20 _______ 9.4

_t19 _____ 1945 ____14.4 _ 11.9 ____ 13.15 _______ 9.3

_t19 _____ 1995 ____13.6 _ 12.7 ____ 13.15 _______ 9.3

_t21 _____ 1730 ____15.3 _ 10.9 ____ 13.10 _______ 9.2

_t21 _____ 1999 ____15.6 _ 10.6 ____ 13.10 _______ 9.2

_t23 _____ 1779 ____15.2 _ 10.9 ____ 13.05 _______ 9.1

_t23 _____ 1961 ____15.2 _ 10.9 ____ 13.05 _______ 9.1

_t23 _____ 1989 ____14.6 _ 11.5 ____ 13.05 _______ 9.1

_t23 _____ 2013 ____13.7 _ 12.4 ____ 13.05 _______ 9.1

_t27 _____ 1811 ____13.7 _ 12.3 ____ 13.00 _______ 9.0

_t27 _____ 1865 ____16.3 __ 9.7 ____ 13.00 _______ 9.0

_t29 _____ 1825 ____15.1 _ 10.8 ____ 12.95 _______ 8.9

_t29 _____ 1958 ____15.1 _ 10.8 ____ 12.95 _______ 8.9

_t31 _____ 1857 ____14.5 _ 11.3 ____ 12.90 _______ 8.8

_t31 _____ 1978 ____14.1 _ 11.7 ____ 12.90 _______ 8.8

_t31 _____ 2017 ____13.6 _ 12.2 ____ 12.90 _______ 8.8

_ 34 _____ 2009 ____ 14.3 _ 11.4 ____ 12.85 _______ 8.7

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

Note, about half of these top 35 (counting this year) occurred from 1968 to present.

2023 could easily settle into 2nd place and has a chance to finish first here as well. 

[ItNeverSnowsInWindsor]

12 hours ago, Don said:

Yes, I think most CET guesses are still in the game.

The latest GFS run looks on the cold side!

[Summer Sun]

15.6c to the 10th

5.1c above the 61 to 90 average
3.8c above the 81 to 10 average

[rwtwm]

8 hours ago, prolongedSnowLover said:

The latest GFS run looks on the cold side!

A couple of days ago I was worried I'd undershot with my guess. It looked like we'd get a quasi-stationary low just off to the west. Not massively warm by day, but virtually no diurnal range. 

In just 2/3 days the script has completely flipped! 

[Relativistic]

Should get a decent run of single-figure means from Saturday onwards.

[Frigid]

GFS 00z would obliterate the current CET I reckon, possibly going into the 11s. An outlier of course, but seen it's been a recurring theme within the models to go colder in the second half I wouldn't be surprised if it came off. 

[Metwatch]

That's about it for how high it will get now, the descent begins from tomorrow's value (up to 11th, today).

If July was a bit cooler, we would be ahead of it for the first 10 days of October! One of the warmest first 10 days to any October I think, if @Roger J Smith can do the more in depth analysis of the data and see where 2023 is compared to other years.

I don't think it will be warmer than May now, but still depends what the final 7-10 days is like.

[Addicks Fan 1981]

3 hours ago, Frigid said:

GFS 00z would obliterate the current CET I reckon, possibly going into the 11s. An outlier of course, but seen it's been a recurring theme within the models to go colder in the second half I wouldn't be surprised if it came off. 

According to the NOAA we should be turning a blind eye to that op run.   We ought to be looking at the ECMWF ensemble mean, this isn't me telling the site what to do, it is advice and to be better informed.   

[Roger J Smith]

The CET 1st -10th for 2023 ranks third behind 1921 (16.5) and 1959 (16.0). 

4th was (15.3) 2011

5th was 14.9 (1908)

t-6th were 14.8 (1949) and 14.8 (1825)

8th was 1995 (14.5)

9th was 1876 (14.3)

10th was 1969 (14.2)

close to top ten: 1859 (14.1), 1985 (14.1), 1983 (14.0). (2001 was 13.8)

 

 

 

[Dancerwithwings]

with what’s forecasted my 12.4c is looking better than anticipated 

[WYorksWeather]

14 minutes ago, Dancerwithwings said:

with what’s forecasted my 12.4c is looking better than anticipated 

I really, very strongly doubt the GFS, especially when it disagrees so strongly with the ECM, which by most objective criteria is the better model. I think your guess is very much still in the game. Partly what I want to happen with my guess, but I think at least partly justified IMO.

[Roger J Smith]

Largest drop in CET from 1-10 running mean to end of Oct mean was 5.2 deg in 1926 (13.3 to 8.1). Second largest was 4.5 deg in 1859 (14.1 to 9.6), tied third are 4.2 deg in 1819 (13.3 to 9.1) matched in 1931 (13.0 to 8.8) and fifth is 4.0 deg in 1825 (14.8 to 10.8), sixth is 3.9 deg in Oct 1997 which fell from 13.9 to 10.0. Seventh place goes to 1896 (10.7 to 6.9, 3.8 drop). Two warm Octobers (1921, 1959) are close at 3.7 but despite those falls they finished quite respectably. 1895 fell from 10.7 to 7.1, quite a steady fall from record warmth around 18 to 25 September.

To match the 1926 value, 2023 would need to finish on 10.4. It would take an average of 7.9 for 11-31 Oct to do that. To match the  recent 1997 value would require an outcome of 11.7, an average of 9.9 today to end of October would work for that. 

Today's 12z GFS output places this sort of fall within the realm of possibility, if you believe in GFS cold scenarios. I am always a bit of a skeptic about them but we'll see. A more sedate average of 10.5 today to end would yield an outcome of 12.2 C, still a relatively warm outcome. We know it will fall some distance, even 1921 and 1959 did so, but it remains to be seen if it's a moderate or a massive plunge. 

[Summer Sun]

15.5c to the 11th

5.0c above the 61 to 90 average
3.7c above the 81 to 10 average

[Addicks Fan 1981]

15 hours ago, Roger J Smith said:

Largest drop in CET from 1-10 running mean to end of Oct mean was 5.2 deg in 1926 (13.3 to 8.1). Second largest was 4.5 deg in 1859 (14.1 to 9.6), tied third are 4.2 deg in 1819 (13.3 to 9.1) matched in 1931 (13.0 to 8.8) and fifth is 4.0 deg in 1825 (14.8 to 10.8), sixth is 3.9 deg in Oct 1997 which fell from 13.9 to 10.0. Seventh place goes to 1896 (10.7 to 6.9, 3.8 drop). Two warm Octobers (1921, 1959) are close at 3.7 but despite those falls they finished quite respectably. 1895 fell from 10.7 to 7.1, quite a steady fall from record warmth around 18 to 25 September.

To match the 1926 value, 2023 would need to finish on 10.4. It would take an average of 7.9 for 11-31 Oct to do that. To match the  recent 1997 value would require an outcome of 11.7, an average of 9.9 today to end of October would work for that. 

Today's 12z GFS output places this sort of fall within the realm of possibility, if you believe in GFS cold scenarios. I am always a bit of a skeptic about them but we'll see. A more sedate average of 10.5 today to end would yield an outcome of 12.2 C, still a relatively warm outcome. We know it will fall some distance, even 1921 and 1959 did so, but it remains to be seen if it's a moderate or a massive plunge. 

Think the ECMWF could be mentioned here a bit more as ECMWF has a much better verification record than the GFS.    

[Roger J Smith]

I wasn't endorsing GFS, just saying if a certain run verified drops of 4 to 5 C would occur, as was case in years cited. 

Would be interested in seeing verification stats of various European forecasts by different sources, I saw stats for NA and really not a big difference. Also different products, Euro runs only ten days and you are citing weekly outlooks past ten days I believe? In current situation difference arises inside ten days. Will take a look at 12z Euro later and see if it looks a lot different cf GFS. Today's 12z GFS run suggests a slow fall to (and including Fri 13 Oct) to around 15.0, and a faster decline 14 to 28 Oct (average 8 C, a fall to 11.5 by nearly end of October). 

Possibly you could give predictions using European or any sources and we can review around 28 Oct. I don't endorse it, could be too cold and I would prefer it was too cold (12.4 contest prediction). Quite aware of GFS track record on unfulfilled cold spells at ten days, lost count of total so far.

 

[The PIT]

Sunny Sheffield at 15.9 +3.1C above average. Rainfall 15.6mm 18.8% of the monthly average.

Big drop for today and a possible rise up again for Friday. Tomorrow will decide if it's dry first half of the month or not for us.

[The PIT]

Sunny Sheffield down to 15.4C +2.7C degrees above normal. Rainfall up to 26.5mm 32.1% of the average.

Rain much lighter than forecast so first half of the month will be average or just below.

[Summer Sun]

15.1c to the 12th

4.5c above the 61 to 90 average
3.3c above the 81 to 10 average

[Roger J Smith]

Will post an EWP update on 14th to catch full extent of today's additional rainfall, but looks to be heading for 110-120 at least and is probably around 45 now. That colder guidance yesterday was also drier by a large differential (was thinking 70-80 as total yesterday but now another 70 after today looks quite probable).

CET not quite as strong a drop on today's GFS guidance but still a steady decline into the 12s certainly, not a very strong signal for anything above 12.5 at present (on GFS). I looked at European and Canadian to ten days and don't see big differences in today's guidance that far at least. All guidance shows a cooler spell next week. GFS backs off on a continuation of that and begins to show faint signs of a late increasing trend which would surprise nobody after last year (20-31 Oct ran quite high on CET and set a few daily records). 

 

 

[Metwatch]

56 minutes ago, Roger J Smith said:

Will post an EWP update on 14th to catch full extent of today's additional rainfall, but looks to be heading for 110-120 at least and is probably around 45 now. That colder guidance yesterday was also drier by a large differential (was thinking 70-80 as total yesterday but now another 70 after today looks quite probable).

Should see the EWP at around 50-60mm following today's deluge, today's value should be out by Sunday morning.

Quite uncertain how much more rain we get during the second half of October, with high pressure moving somewhere to the north east of UK later next week. GFS 18z is very dry, but other runs have been much wetter.

Latest ECM isn't too wet either up to the 23rd, with a lot of that over central England from today. Could finish anywhere from 75 - 120mm +, it's a total guess for now. My guess of 95mm seems safe enough at the moment.

Edited October 13, 2023 by Metwatch

[Summer Sun]

15.0c to the 13th

4.5c above the 61 to 90 average
3.3c above the 81 to 10 average

[The PIT]

Sunny Sheffield down to 15C +2.4C above normal. Rainfall 29.8mm 36% of the monthly average.

So dryish first half of the month.

[Roger J Smith]

EWP is probably around 55 mm now and will reach 125-140 mm according to GFS guidance to end of month now. 

CET projections have warmed slightly, would say mid 12 range looks best at present. 

[The PIT]

Sunny Sheffield down to 14.7C +2.2C above average. Rainfall up to 30.4mm 36.7% of average.

Should keep on falling however the fall should slow later this week.