November 2023 C.E.T. and EWP contests -- final month of the 2022-23 competitions

[Summer Sun]

8.6c to the 19th

2.2c above the 61 to 90 average
0.9c above the 81 to 10 average

[TillyS]

15 hours ago, gaia rules said:

"The highest annual mean CET ever recorded was 11.15, which is 1.68 higher than normal. To beat this record the
anomaly must be higher than 2.04 for the remainder of this year."

No chance now! CET is sliding down and down 

I’m always a bit worried when people say ‘no chance’ because the UK weather has a tendency to confound.

When you say that the ‘CET is sliding down and down’ don’t we need to clarify two different things? The CET will slide down and down because it’s the end of November and we are coming into December. So it’s supposed to drop from here.

The question is whether the anomaly stays above or below 2.04C for the remainder of the year.

I think you’re right, that it’s unlikely. But it’s not certain.

x

[reef]

2 hours ago, TillyS said:

I’m always a bit worried when people say ‘no chance’ because the UK weather has a tendency to confound.

When you say that the ‘CET is sliding down and down’ don’t we need to clarify two different things? The CET will slide down and down because it’s the end of November and we are coming into December. So it’s supposed to drop from here.

The question is whether the anomaly stays above or below 2.04C for the remainder of the year.

I think you’re right, that it’s unlikely. But it’s not certain.

x

Indeed, you cant ever say never these days. It should be remembered that the anomaly shown on the Hadley site is compared to the 1961-1990 average. On that average, December was 4.5C. Say November's figure cools over the next 10 days and we require +2.5C in December to beat the record. That's only a CET of 7.0C and we've just had a 9.6C December as recently as 2015.

Its looking unlikely but its too early to rule it out.

[The PIT]

Sunny Sheffield up to 8.2C -0.1C below average. Rainfall up 81.9mm 92.8% of the monthly average.

A slow rise to Thursday then a equally slow drop afterwards. The cold snap at  the moment looks set to last until the end of the month. Also dry end so tonight's showers may the last of the months rain and a month that was looking like being well above average could end up a shade under average rainfall.

[gaia rules]

8 hours ago, TillyS said:

I’m always a bit worried when people say ‘no chance’ because the UK weather has a tendency to confound.

When you say that the ‘CET is sliding down and down’ don’t we need to clarify two different things? The CET will slide down and down because it’s the end of November and we are coming into December. So it’s supposed to drop from here.

The question is whether the anomaly stays above or below 2.04C for the remainder of the year.

I think you’re right, that it’s unlikely. But it’s not certain.

x

Hi Tilly yes you are absolutely right and I was being a bit gung ho with this weekend's cold looking to become fairly established  in the GFS 18Z last night! We just need the cold snap to be short lived (which is a stronger possibility with todays runs as the Iceland high has receded south a tad ) and continuous SW flow in December to push get that 2.04 required. 

 

Edited November 20, 2023 by gaia rules

[WYorksWeather]

Just working out scenarios - I think we're now at the stage where even a truly frigid end to November couldn't prevent an 11th above average month?

Call the anomaly something like 2.0C to the 22nd. Then with a quarter of the month left to play with, we'd need an average anomaly somewhere near -6C to end at zero. That's a CET mean near 3C, which I think is pretty infeasible!

In which case, all eyes on December for whether the 12/12 will finally be achieved this year. Might be an interesting chase, especially if the cold spell does carry on into early December.

Edited November 20, 2023 by WYorksWeather

[The PIT]

Sunny Sheffield at 8.1C -0.1C below average. Rainfall 82.4mm 93.3% of the monthly average.

[Summer Sun]

8.6c to the 20th

2.2c above the 61 to 90 average
1.0c above the 81 to 10 average

[Summer Sun]

8.6c to the 21st

2.2c above the 61 to 90 average
1.1c above the 81 to 10 average

[Roger J Smith]

EWP currently around 113 mm, GFS guidance not quite as dry as previous days, now adding 25-30 mm to total by end of Nov (for near 140 mm outcome) ... would take a real deluge in Dec near record values to get past second place for yearly rainfall now and first (after 140 verified) would require a new Dec record. Probably a top five to top ten range is more realistic.

CET will likely edge up to 8.7 or even 8.8 before dropping away steadily after Friday, but I can't see it falling below 7.5; assuming 8.8 after 23 days, last seven would need to average 5.7 to drop average to 8.0, and 3.4 is needed to drop to 7.5; current GFS guidance suggests 7.8 or 7.9 is likely outcome.

I won't be surprised if end of Nov disturbances intensify closer to time and bring a wintry mix of precip to central England around 28-30 Nov, so EWP could go a bit above projections, and it could edge up CET outcome if last two minima are forced up a bit. 

[The PIT]

Sunny Sheffield at to 8.2C +0.1C above average. Rainfall at 82.8mm 93.8% of the monthly average.

[Summer Sun]

8.6c to the 22nd

2.2c above the 61 to 90 average
1.2c above the 81 to 10 average

[The PIT]

Sunny Sheffield up to 8.4C +0.4C above normal. Rainfall up 82.9mm 93.9% of the monthly average.

[Metwatch]

Going to see quite the tumble to the daily CET updates once tomorrow passes. Maybe the chance of a low 7s is possible? I don't think a sub 7C final value is possible anymore. We would need to have an end to this month like November 2010 which would give snow cover and a few sub zero daytime maxes with frigid nights.

EWP may go up as those lows come from the Azores and give a lot of rain or snow. Expecting it to exceed my guess.

Edited November 23, 2023 by Metwatch

[damianslaw]

A week to go and almost certain a finish in the 7s will be where we are, but exactly where who knows. A good bet might be in the middle, 7.5 degrees.

[Summer Sun]

8.7c to the 23rd

2.2c above the 61 to 90 average
1.4c above the 81 to 10 average

[The PIT]

Sunny Sheffield still at 8.4C +0.6C above average. Rainfall 84.1mm 95.2% of the monthly average.

Using the local forecast gives a final value of 7.5C  +0.5C above normal.

 

[Roger J Smith]

EWP is currently close to 112 mm and last few runs were between 20-30 mm additional, so outcomes around 132-142. I already adjusted scoring table last night for 130 mm, any outcome in that range will produce similar results. It's quite close for positions 2 to 12 but snowray is probably safe already, only a really low outcome already passed could have threatened their lead. The exact value at end of Nov will determine rest of top ten in quite a close finish, so if you take a look, keep in mind none of the positions shown after the leader are a done deal yet. 

CET has as expected edged up on the last gasp of the mild regime, so the math tells us outcome is unlikely to be much lower than 7.5 C, even if the average for 24-30 Nov is 3.0 (and GFS says closer to 4.0), the outcome would be 7.4 C. For 4.0 it would be 7.6 C. It will set up a battle with 2022  for third and fourth warmest autumn (I made up a table for that early in the thread, on 6 Nov), but 2006 is safe now to hold on to first, and IIRC second (2011) required a value of 8.0 so that one could be safe also. It will end up quite close to last year's average (7.3). Actually since we're talking about it, here is the table reproduced below:

Top 15 CET averages for autumn, and exact data to reveal 2023 options to tie ... 

Rank ____ Year _____ Avg ____ SEP _ OCT _ NOV ____ 2023 to tie

_ 01 ____ 2006 _____ 12.6 ____ 16.9 _ 12.9 _ 8.0 ____ 8.7

_ 02 ____ 2011 _____ 12.4 ____ 15.1 _ 12.5 _ 9.5 ____ 8.0

_ 03 ____ 2022 _____ 12.1 ____ 14.4 _ 12.8 _ 9.2 ____ 7.3

_ 04 ____ 2014 _____ 12.0 ____ 15.1 _ 12.3 _ 8.5 ____ 6.8

_t05 ____ 1731 _____ 11.8 ____ 15.3 _ 12.3 _ 7.8 ____ 6.3

_t05 ____ 1730 _____ 11.8 ____ 15.3 _ 10.9 _ 9.2 ____ 6.3

_ 07 ____ 2021 _____ 11.7 ____ 16.0 _ 12.0 _ 7.2 ____ 6.1

_t08 ____ 1818 _____ 11.6 ____ 13.3 _ 12.0 _ 9.5 ____ 5.7

_t08 ____ 1729 _____ 11.6 ____ 16.6 _ 10.1 _ 8.1 ____ 5.7

_t10 ____ 1959 _____ 11.5 ____ 14.9 _ 12.6 _ 7.1 ____ 5.5

_t10 ____ 1949 _____ 11.5 ____ 16.3 _ 11.7 _ 6.6 ____ 5.5

_ 12 ____ 2005 _____ 11.5*____ 15.2 _ 13.0 _ 6.1 ____ 5.3

_ 13 ____ 2009 _____ 11.4 ____ 14.3 _ 11.4 _ 8.6 ____ 5.3

_t14 ____ 2001 _____ 11.4 ____ 13.4 _ 13.2 _ 7.5 ____ 5.0

_t14 ____ 1978 _____ 11.4 ____ 14.1 _ 11.7 _ 8.3 ____ 5.0

-------------------

(note: in above table, order is from metoffice table, ties are established by me if two-decimal average is a tie (or if total of three autumn months is same)). 

* ... even so, their calculations seem to be based on some kind of weighting, for example, 2005 works out to 11.43 in the equal weight system used in CET legacy with a two-decimal table. 2005 is actually tied with 2009 in terms of total, but as their system came to different one-decimal values, I did not show a tie for them. 

Notice three in a row in list 1729-31 and 2023 will repeat this feat. 2020 is listed as 30th (11.0), one of six and the last of them to appear. 

Interesting to see that warmest Sep and Oct are in list but warmest Nov (1994) was part of a 10.9 average and four years are listed 31st to 35th (will become 32nd to 36th after 2023 slides into top ten). 1994 is given as second last of those four so appears in 34th about to be 35th. 

________________________

Also from a discussion back on page four, it was stated that to beat 2022 for annual CET, it would require Nov and Dec to total 15.0, so as we are headed for 7.5 or so, it will take a repeat of that for a very mild Dec, otherwise 2023 will be fighting it out with 2014 for second (and that would take a fairly high Dec outcome also). 

Edited November 25, 2023 by Roger J Smith

[WYorksWeather]

5 hours ago, Roger J Smith said:

EWP is currently close to 112 mm and last few runs were between 20-30 mm additional, so outcomes around 132-142. I already adjusted scoring table last night for 142 mm, any outcome in that range will produce similar results. It's quite close for positions 2 to 12 but snowray is probably safe already, only a really low outcome already passed could have threatened their lead. The exact value at end of Nov will determine rest of top ten in quite a close finish, so if you take a look, keep in mind none of the positions shown after the leader are a done deal yet. 

CET has as expected edged up on the last gasp of the mild regime, so the math tells us outcome is unlikely to be much lower than 7.5 C, even if the average for 24-30 Nov is 3.0 (and GFS says closer to 4.0), the outcome would be 7.4 C. For 4.0 it would be 7.6 C. It will set up a battle with 2022  for third and fourth warmest autumn (I made up a table for that early in the thread, on 6 Nov), but 2006 is safe now to hold on to first, and IIRC second (2011) required a value of 8.0 so that one could be safe also. It will end up quite close to last year's average (7.3). Actually since we're talking about it, here is the table reproduced below:

Top 15 CET averages for autumn, and exact data to reveal 2023 options to tie ... 

Rank ____ Year _____ Avg ____ SEP _ OCT _ NOV ____ 2023 to tie

_ 01 ____ 2006 _____ 12.6 ____ 16.9 _ 12.9 _ 8.0 ____ 8.7

_ 02 ____ 2011 _____ 12.4 ____ 15.1 _ 12.5 _ 9.5 ____ 8.0

_ 03 ____ 2022 _____ 12.1 ____ 14.4 _ 12.8 _ 9.2 ____ 7.3

_ 04 ____ 2014 _____ 12.0 ____ 15.1 _ 12.3 _ 8.5 ____ 6.8

_t05 ____ 1731 _____ 11.8 ____ 15.3 _ 12.3 _ 7.8 ____ 6.3

_t05 ____ 1730 _____ 11.8 ____ 15.3 _ 10.9 _ 9.2 ____ 6.3

_ 07 ____ 2021 _____ 11.7 ____ 16.0 _ 12.0 _ 7.2 ____ 6.1

_t08 ____ 1818 _____ 11.6 ____ 13.3 _ 12.0 _ 9.5 ____ 5.7

_t08 ____ 1729 _____ 11.6 ____ 16.6 _ 10.1 _ 8.1 ____ 5.7

_t10 ____ 1959 _____ 11.5 ____ 14.9 _ 12.6 _ 7.1 ____ 5.5

_t10 ____ 1949 _____ 11.5 ____ 16.3 _ 11.7 _ 6.6 ____ 5.5

_ 12 ____ 2005 _____ 11.5*____ 15.2 _ 13.0 _ 6.1 ____ 5.3

_ 13 ____ 2009 _____ 11.4 ____ 14.3 _ 11.4 _ 8.6 ____ 5.3

_t14 ____ 2001 _____ 11.4 ____ 13.4 _ 13.2 _ 7.5 ____ 5.0

_t14 ____ 1978 _____ 11.4 ____ 14.1 _ 11.7 _ 8.3 ____ 5.0

-------------------

(note: in above table, order is from metoffice table, ties are established by me if two-decimal average is a tie (or if total of three autumn months is same)). 

* ... even so, their calculations seem to be based on some kind of weighting, for example, 2005 works out to 11.43 in the equal weight system used in CET legacy with a two-decimal table. 2005 is actually tied with 2009 in terms of total, but as their system came to different one-decimal values, I did not show a tie for them. 

Notice three in a row in list 1729-31 and 2023 will repeat this feat. 2020 is listed as 30th (11.0), one of six and the last of them to appear. 

Interesting to see that warmest Sep and Oct are in list but warmest Nov (1994) was part of a 10.9 average and four years are listed 31st to 35th (will become 32nd to 36th after 2023 slides into top ten). 1994 is given as second last of those four so appears in 34th about to be 35th. 

________________________

Also from a discussion back on page four, it was stated that to beat 2022 for annual CET, it would require Nov and Dec to total 15.0, so as we are headed for 7.5 or so, it will take a repeat of that for a very mild Dec, otherwise 2023 will be fighting it out with 2014 for second (and that would take a fairly high Dec outcome also). 

I think Met Office could be using daily averages? So the three-monthly average will slightly favour October (31 days). That could account for any small discrepancies and would be my best guess.

[The PIT]

Sunny Sheffield down to 8.3C +0.7C above average. Rainfall unchanged.

[Summer Sun]

8.6c to the 24th

2.2c above the 61 to 90 average
1.4c above the 81 to 10 average

[damianslaw]

8 hours ago, Summer Sun said:

8.6c to the 24th

2.2c above the 61 to 90 average
1.4c above the 81 to 10 average

Is each daily update based on 9am - 9am of previous 24 hours, makes sense if the case that the CET didn't drop, but the last 9am to 9 am period should bring a drop. Mid to high 7s likely finish mark.

[Roger J Smith]

27 minutes ago, damianslaw said:

Is each daily update based on 9am - 9am of previous 24 hours, makes sense if the case that the CET didn't drop, but the last 9am to 9 am period should bring a drop. Mid to high 7s likely finish mark.

I think that is correct for reported max, min is an earlier 24h interval like 9 pm to 9 pm. So as you say, next six reports (incl today's values reported tomorrow) will be full-on cold. Unless there are odd trends, most days will reflect usual morning low and afternoon max in those reporting periods, but it won't catch a midnight low if it ends at 9 pm and it could catch a low evening value from a previous day. It is rare for max to occur overnight or into first part of next morning so that sort of data contamination would be rare. I don't know what protocols were in place for CET max and min periods before recent years. As with the choice of 1961-1990 for normals, it is quirky UK practice not followed in various other countries, can't say for all but I know for a fact US, Canada and Ireland use calendar day for reporting first order climate stats and have done so for a long time but back in the distant past they produced data from different time protocols similar to these UK protocols, and it meant that on occasion, a cold midnight low was not in data and there were never as many compensating errors in maxima, so data sets were adjusted and this caused a bit of a ruckus over "data manipulation" as it appeared to skeptics that the intent was to make the past look colder. I waded into that and said, look I am not a mainline AGW person myself but I know this is legit because you can see the data were not to modern standards, you get consecutive days with temperature gaps between ranges and that is not possible when your max and min are calendar day. (day 1 min and day 2 max will be same when a strong cold front moves in overnight). 

[Roger J Smith]

So it could be a bit unclear what I was saying about intervals, the value for 24 Nov (Friday) in that case would be based on 

max: 0900 Friday 24 to 0900 Sat 25

min: 2100h Thurs 23 to 2100h Fri 24

and possibly even earlier for min, like 1800h 23rd to 1800h 24th ... you can see this is going to adjust more minima up, than it would adjust maxima down, compared to calendar day reporting. In a continuous warming situation over two days, you could even get a "day" with both max and min actually recorded on different days, min from previous day and max from next day. This hypothetical situation with just every three hours to simplify it, shows how that would happen: 

2100h Jan 7, 19 BC ____ -20 C

2400h Jan 7, 19 BC ____ -15 C

0300h Jan 8, 19 BC ____ -10 C

0600h Jan 8, 19 BC _____ -7 C

0900h Jan 8, 19 BC _____ -4 C 

1200h Jan 8, 19 BC _____ -2 C

1500h Jan 8, 19 BC _____ -1 C

1800h Jan 8, 19 BC _____ 0 C

2100h Jan 8, 19 BC _____ 1 C

2400h Jan 8, 19 BC _____ 1 C

0300h Jan 9, 19 BC _____ 2 C

0600h Jan 9, 19 BC _____ 4 C

0900h Jan 9, 19 BC _____ 7 C 

Reported max 7 C and min -20 C, calendar day would be 1 C and -15 C, ending 0900 for both would be 7 C and -4 C. 

Reported means would be -6.5, -7.0 and +1.5, so it makes a difference. 

 

[The PIT]

Sunny Sheffield down to 8.1C +0.5C above average. Rainfall 84.1mm 95.2% of the monthly average