October 2023 C.E.T. and EWP contests

[Stationary Front]

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

[reef]

21 minutes ago, Stationary Front said:

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

Almost certainly. 2006 is the likely closest but the first half of that October was around 13.3C if I remember correctly, so this year will easily beat it.

[MattStoke]

Now level with last year.

[Summer Sun]

15.2c to the 7th

4.7c above the 61 to 90 average
3.3c above the 81 to 10 average

[Roger J Smith]

First record set in CET of current warm spell on 7th.

New record high mean 17.5 (previous 16.8 1921).

Failed by 0.1 to tie record high max 21.5 (set 1959) _ also 21.4 1965 (v2) which was legacy CET record at 21.5

Did not quite match high min (13.7 1900) ... 13.5

Record high means for 8th to 11th are all in mid-17s so could be a bit more difficult, the record just broken was tail end of a three-day record interval in 1921. 

 

[The PIT]

Sunny Sheffield up to 15.2C +2.0C above normal. Rainfall unchanged.

[SqueakheartLW]

21 hours ago, MattStoke said:

Now level with last year.

Last year it was the CET maxes that got us the record 11.15C mean year. This year it has been more about the higher CET mins holding the mean up.

[Summer Sun]

15.4c to the 8th

4.9c above the 61 to 90 average
3.6c above the 81 to 10 average

[Addicks Fan 1981]

According to this we could be potentially smashing the 2001 record and consigning it to history.   

 

Edited October 9, 2023 by Addicks Fan 1981

[Don]

9 minutes ago, Addicks Fan 1981 said:

According to this we could be potentially smashing the 2001 record and consigning it to history.   

 

All current record warm months are tenterhooks now and what's more, new record months might not last long!!

[Roger J Smith]

Current GFS shows no return to warmth after the middle of this week, and would drop CET steadily after a peak near 16.0 on Wed 11th, next fourteen days average only around 9 C and that leads to a drop in CET to near 12 C. Could be overdone though.

EWP is currently around 14 mm and would reach perhaps 60 mm by 25th according to GFS. Considerably wetter in some parts of Wales and northwest England, Scotland and Ireland where totals of 120-200 mm are predicted, dry east and southeast England holds down the overall grid average. 

Yesterday (8 Oct) did not set any new CET records, 22.5/16.7/10.9 all below existing records, max (23.1) and mean (17.5) from 1995 and min record (13.2) a tie (1969, 2005). 

[saintkip]

13 hours ago, The PIT said:

Sunny Sheffield up to 15.2C +2.0C above normal. Rainfall unchanged.

Can someone explain why Sheffields average temp up to now is normally 13.2c whilst the average temp for England is 11.8c this doesn’t make sense.

[LetItSnow!]

Not expecting it to make much dent but there’s some signs for some abnormal cold across Europe building. It would be funny if this was a month with a notable warm first half but some chill in the second half, with an unexceptional CET. Not a bet I’d want to make at this time though!

[Roger J Smith]

I would say the most likely reason is that PIT's weather station is in a relatively warm location perhaps boosted by urban heat island which is not present for the CET (I assume the previous poster with the question knows where the central England recording sites are located, if not, they are in rural areas of Lancs (Stonyhurst) and southwest midlands (Pershore) plus suburban Luton area  (Rothamsted) but with a correction applied to remove urban effect there.)

Also, I promised to add occasional comparisons for 1991-2020 and for 1-8 October those are 0.2 higher than 1981-2010 (running mean is 12.0) so Oct 2023 sits 3.4 above 1991-2020 average. 

[Roger J Smith]

6 minutes ago, LetItSnow! said:

Not expecting it to make much dent but there’s some signs for some abnormal cold across Europe building. It would be funny if this was a month with a notable warm first half but some chill in the second half, with an unexceptional CET. Not a bet I’d want to make at this time though!

I noted a few days ago in addition to reporting on the ten warmest first halves of October, the largest drops from CET 1-15 to CET end of month, despite fact that in an average October the running mean drops about 1.5 C, there are only eight cases (in 251 years with daily data) of a drop of 3.0 or more, two of them belonging to very warm starts that ended up rather average (1949 and 1825), the others being mostly cases of near average starts followed by very cold second halves (like 1895). The largest drop of 4.1 deg occurred in 1926. If it really does turn cold later this month, that record may be the one under threat, 14.8 to 10.6 for example would do it. 

[cheese]

3 hours ago, saintkip said:

Can someone explain why Sheffields average temp up to now is normally 13.2c whilst the average temp for England is 11.8c this doesn’t make sense.

All three CET stations probably record cooler minimums than Sheffield due to the urban heat island effect, while Stoneyhursrt will record cooler maximums as well. We record higher average temperatures than the CET zone as well (i.e June 2023 had an average temperature of 17.5C here compared to 17.0C for the CET zone). 

Edited October 10, 2023 by cheese

[ItNeverSnowsInWindsor]

It certainly looks interesting from Saturday onwards with GFS still showing a cold pool over Europe with an easterly over us!

[saintkip]

4 hours ago, cheese said:

All three CET stations probably record cooler minimums than Sheffield due to the urban heat island effect, while Stoneyhursrt will record cooler maximums as well. We record higher average temperatures than the CET zone as well (i.e June 2023 had an average temperature of 17.5C here compared to 17.0C for the CET zone). 

Cheers

[Cheshire Freeze]

16 hours ago, Addicks Fan 1981 said:

According to this we could be potentially smashing the 2001 record and consigning it to history.   

 

Looking very doubtful on current output. Looks to turn much colder this weekend with overnight frosts and cool days.

Edited October 10, 2023 by Cheshire Freeze

[Scorcher]

5 hours ago, Cheshire Freeze said:

Looking very doubtful on current output. Looks to turn much colder this weekend with overnight frosts and cool days.

Still plenty of time for that to flip back again. There's a modern trend for warm ends to October. Another warm spell before the end of the month could cancel this cooler spell out.

[Summer Sun]

15.5c to the 9th

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

[The PIT]

Sunny Sheffield at 15.6C +3.5C above average. Rainfall unchanged.

[The PIT]

16 hours ago, saintkip said:

Can someone explain why Sheffields average temp up to now is normally 13.2c whilst the average temp for England is 11.8c this doesn’t make sense.

Mine are just guestimates. Basically I take the final average of the previous month as  a starting point then run line down to the average value for October at the end of the run. Not perfect but it will do. Ideally I should do a daily mean but that's a lot of working out going day by day for the last 30 years. The met office I guess do the daily method.

 

[Don]

6 hours ago, Scorcher said:

Still plenty of time for that to flip back again. There's a modern trend for warm ends to October. Another warm spell before the end of the month could cancel this cooler spell out.

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

[Roger J Smith]

Well the met office used to do it daily but now all we get from them are comparisons with end of month 1961-1990 average (10.5 C). I would guess the running mean for 1961-1990 for today's report would be around 11.5 so that the direct comparison to the other stat provided today would be 4.0 above, not 5.0.

The comparison to 1981-2010 (and 1991-2020 when I add it to discussion) comes from my excel file of CET v2.0 data and it is a differential from a similar stat, average 1 to 9 October in today's case. It's not smoothed which could make the values drop off a little differently from your estimates but I would bet your estimates are pretty close if they fall off at a regular pace. If you wanted to mirror the CET data without doing a lot of work on your data, just look at my tables (posted around 2nd in the thread), take your monthly mean differential from 1981-2010 CET, and add that differential to the values. For example if your October mean for 1981-2010 was 11.2 and CET is 10.6, just add 0.6 to the values you see. If the September differential was very much different, start with that differential and adjust in stages. Suppose your Sept differential is +0.8, then start with that adjustment, and make it +0.7 after ten days and +0.6 after twenty.