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scillydave
27 December 2024 19:30:29
Right, evening all it's time once again to kick off the annual CET competition. I hope you've all had a suitably festive few days and have spent it wisely ruminating on the latest model output. 
Brian has just set the cat amongst the proverbial flying rats with this post...

' I'll stick my neck out and say it looks like we could have one of the most significant January cold spells in years brewing. A large cluster of the GEFS runs appears to maintain cold conditions over most of the UK for an extended period. The ECM and GEM models are also supportive. Of course, snow is another matter entirely. Let's see what things look like tomorrow. '
So are we staring down the barrel of the Day After Tomorrow or is there a Pint of Mild on the way? To help you decide here are the ghosts of January's past:
January Average CET 4.7C 1990 – 2020

Coldest 3 since 1970
1979      -0.04
1987    0.80
1985    0.90

Warmest 3 since 1970
2007      7.00
1975    6.80
1983    6.70

Last 3
2024    4.74
2023    5.20
2022    4.70
2021    3.20

Here (thanks to the legend that is GW) is a reminder of how the CET competitions work for the benefit of everyone but also anyone who would like to join in for the first time. All are welcome to participate.

How do the competitions work?

Each month a new thread is opened a few days in advance of the start of a new month. Your challenge is to predict the mean Central England Temperature (CET) for the following month. The CET is the longest running temperature series and goes back to the mid 1600's. Each month I'll post some statistics about the CET for that month in recent years.

Predictions can be made either to one or two decimals (the actual data is published to two decimals). The closest person or persons to the final figure at the end of the month are declared the winner for that month. There are no prizes. This competition is just a bit of fun and the chance to amaze your fellow posters with your skill and foresight in predicting the weather (or you can just make a random guess!).

We use the Hadley data for the purposes of this competition which is maintained by the Met Office. Provisional figures are published daily with a final adjusted number usually issued on the first day of the following month.

In addition to the monthly competition there is an annual competition which runs throughout the year. The annual competition keeps a running total of the cumulative prediction errors from each month for each person. Absolute differences are used so it makes no difference if you overpredict or underpredict the CET in any given month. At the end of the year the person with the lowest cumulative prediction error after totalling each of the 12 months is declared the winner for the year. This is always a hard fought contest and requires a consistency of good predictions in order to win.
Entries after 2359 on the final day of the month will only be accepted at my discretion if I consider there is a reasonable excuse. No entries will be accepted after the 2nd of the month. There is a penalty of 0.2C for each day that a prediction is late.

Summary of important points

- Predictions can be made up to 23:59 on the final day of the month before the one to which the prediction relates. Entries may be accepted up to two dates late but with a penalty.

- All predictions should be made by private message to me.

- Once you have sent your prediction you are only permitted to change it once prior to the deadline. Any subsequent amendments will be ignored.

- You may make a prediction to either one or two decimals. You can predict the same figure as someone else (except for a 2022 whole year CET prediction which must be unique).

- Where two members have the same cumulative prediction error for the year at the end of any month, the order of ranking in the competition table will be determined by which person has had the closest prediction to the actual CET in any month. If there is a still a tie I then look to the second closest prediction for each person and so on until the tie is broken. If the tie cannot be broken (very unlikely by December but can happen in the first couple of months of the year) then each person impacted is awarded the same position in the table.

Missed predictions

If a person participating in the annual CET competition does not make a prediction in any one month (including January) their prediction error for that month will be calculated as follows:

- the upper quartile (75th percentile) of the prediction errors of all the people in the annual competition who did make a prediction for that month will be calculated at the end of the month plus a penalty of 0.4C (to tie in with the penalties for late predictions);

The result of the above calculation will be used as the CET prediction error for any person who misses a prediction in a particular month subject to one further point:

- If, for any person, their average monthly prediction error for all the previous months in the year to date is higher than the 75th percentile of errors (across all entrants), then the person's average prediction error will be substituted instead of the 75th percentile figure. This override is only likely to apply to those people towards the foot of the table who have very made very large errors in previous months and hence is no likely to be of significance to the overall result.

One final important point. If you want to be included in the year long competition you may not miss more than two predictions during a calendar year. If a third prediction is missed that person will be eliminated from the annual competition (otherwise it would mean 25% or more of the annual error being calculated on non-existent predictions which would reduce the credibility of the competition too much). However, that person can continue to make predictions for the purpose of the monthly competition.

That's all from me - Admin I'd be grateful if you could sticky the Thread.
Good luck everyone!
Currently living at roughly 65m asl North of Cowbridge in the Vale of Glamorgan.

Formerly of, Birdlip, highest village in the Cotswolds and snow heaven in winter; Hawkinge in Kent - roof of the South downs and Isles of Scilly, paradise in the UK.
scillydave
27 December 2024 19:32:41
P.s. So it's all above board I'll post my prediction here before the 31st - can everyone else PM me.
Currently living at roughly 65m asl North of Cowbridge in the Vale of Glamorgan.

Formerly of, Birdlip, highest village in the Cotswolds and snow heaven in winter; Hawkinge in Kent - roof of the South downs and Isles of Scilly, paradise in the UK.
Windy Willow
30 December 2024 13:52:04
Bumping this so that a Mod will sticky it soon and so it doesn't disappear.

South Holland, Lincs 5m/16ft ASL

When I saw corruption, I was forced to find truth on my own. I couldn't swallow the hypocrisy.

Barry White


It’s the end of the world as we know it (and I feel fine) - R.E.M.
Caz
  • Caz
  • Advanced Member
30 December 2024 17:55:10
My guess is in!  

Market Warsop, North Nottinghamshire.
Join the fun and banter of the monthly CET competition.
scillydave
30 December 2024 21:09:35
Good to see the first couple of predictions trickling in to my inbox which also means it's high time I made mine.
What a difficult month to call!
I'm going for 2.95c (a cold first 10 -14 days followed by a significant warm up)
Good luck everyone. 

Currently living at roughly 65m asl North of Cowbridge in the Vale of Glamorgan.

Formerly of, Birdlip, highest village in the Cotswolds and snow heaven in winter; Hawkinge in Kent - roof of the South downs and Isles of Scilly, paradise in the UK.
Hungry Tiger
30 December 2024 21:11:30
Well done for taking this on and commencing January. 
I've just stickied it for you
Gavin S. FRmetS.
TWO Moderator.
Contact the TWO team - [email protected]
South Cambridgeshire. 93 metres or 302.25 feet ASL.


johncs2016
30 December 2024 23:05:56
Just noticed a typo in the title of this thread as it should be for January 2025 and not January 2024 as stated.

The north of Edinburgh, usually always missing out on snow events which occur not just within the rest of Scotland or the UK, but also within the rest of Edinburgh.
scillydave
31 December 2024 00:42:48

Just noticed a typo in the title of this thread as it should be for January 2025 and not January 2024 as stated.

Originally Posted by: johncs2016 


Good spot John - thank you! 😊
Currently living at roughly 65m asl North of Cowbridge in the Vale of Glamorgan.

Formerly of, Birdlip, highest village in the Cotswolds and snow heaven in winter; Hawkinge in Kent - roof of the South downs and Isles of Scilly, paradise in the UK.
Hungry Tiger
31 December 2024 10:44:13
Just put my figures in. 🙂 Going for a slightly cold one. 
Gavin S. FRmetS.
TWO Moderator.
Contact the TWO team - [email protected]
South Cambridgeshire. 93 metres or 302.25 feet ASL.


Ally Pally Snowman
31 December 2024 10:47:36
Basically impossible guess this one. Latest GFS 6z would be 0c ish cet after 12 days. Ecm much much warmer.
Bishop's Stortford 85m ASL.
lanky
31 December 2024 14:05:29
I think this is going to be one of the toughest months to predict we have ever had

Could end up having a 3-4C error (either high or low) and 2025 will be all over after 1 month for some !


Martin
Richmond, Surrey
Bolty
31 December 2024 15:57:32

I think this is going to be one of the toughest months to predict we have ever had

Could end up having a 3-4C error (either high or low) and 2025 will be all over after 1 month for some !

Originally Posted by: lanky 


Indeed. Looking at the models, it's very tempting to go for a cold month. However, past performances have shown that it doesn't take much for the models to completely evaporate a cold spell. Them backing off the cold, or even the month turning very mild in the second half would completely mess up any cold CET. I've gone for quite a conservative guess, personally.
Scott
Blackrod, Lancashire (4 miles south of Chorley) at 156m asl.
My weather station 
Caz
  • Caz
  • Advanced Member
31 December 2024 18:26:35
I just ignore the model output altogether, so I’m not swayed by it.  Too many times, the start of the month has been completely different to the rest of it.  Not that it does me much good.  lol 
Good luck to you all and Happy New Year!  
Market Warsop, North Nottinghamshire.
Join the fun and banter of the monthly CET competition.
Stormchaser
01 January 2025 20:04:58
Happy New Year - even if the weather hasn't reflected that stance!

Looking forward to a long-awaited return of sunnier conditions tomorrow and Friday.

So how about those CET estimates... I'm not gonna lie, mine for this month was among the least confident I've ever made. Exactly how far north the low pressure, hence area of heavy snow occurs this weekend will have a massive bearing on CET zone temperatures as cold air returns southward next week and then winds fall lighter. If there's lying snow at any of the CET sites, temperatures could plummet toward negative double digits on at least one night.

There were some bonkers GFS runs in recent days. The 12z of 29th put the CET estimate at 5.0°C below the 1991-2020 average as of 14th, then two days later the 00z of 31st put it a staggering 5.7°C below up to that point! That being due to predicting extensive snow cover and a long run of light winds with clear skies. 3-4 nights hitting minus double digits widely. What a thought!

Even this evening, the 12z GFS features a couple of nights reaching -10°C in the west of the zone (next Tue-Wed and Wed-Thu). Yet if the low advances much further north on Sunday than it predicts, such numbers will be very unlikely there due to the lack of lying snow.

Admittedly such enormous uncertainty rather makes a mockery of this competition but hey, we're used to it and at the end of the day, it's just for a bit of fun, or at least what us sort consider to be fun 😁
If you have any problems or queries relating to TWO you can Email [email protected]

https://twitter.com/peacockreports 
2023's Homeland Extremes:
T-Max: 30.2°C 9th Sep (...!) | T-Min: -7.1°C 22nd & 23rd Jan | Wettest Day: 25.9mm 2nd Nov | Ice Days: 1 (2nd Dec -1.3°C in freezing fog)
Keep Calm and Forecast On
Hungry Tiger
01 January 2025 21:54:05

Good to see the first couple of predictions trickling in to my inbox which also means it's high time I made mine.
What a difficult month to call!
I'm going for 2.95c (a cold first 10 -14 days followed by a significant warm up)
Good luck everyone. 

Originally Posted by: scillydave 


Thanks again Scillydave for taking this over.  It's a good hearted competition in which we all learn something. It would be a real shame to lose it.  🙂 BTW a very happy new year to you.  
Gavin S. FRmetS.
TWO Moderator.
Contact the TWO team - [email protected]
South Cambridgeshire. 93 metres or 302.25 feet ASL.


ARTzeman
02 January 2025 11:00:28
IMANSF145       3.4c     Nicks'1BATH     4.3c
Metcheck          5.76c    Anomaly      1.50c
Netweather        7.4c     Anomaly       3.55c
Peasedown St John  4.35c   Anomaly  0.05c.     




Some people walk in the rain.
Others just get wet.
I Just Blow my horn or trumpet
scillydave
02 January 2025 12:04:58
Firstly apologies that there's no fancy table - I had best intentions of creating one but the blooming laptop is broken so I'm posting from my phone🤣

There are a whalloping 29 predictions this month with only a sprinkling above the long term average.  Have we all gone to low or will the absence of Brian's polar bears keep the temperatures freezing and ensure that someone is in with a shout?!

Polar Westerly 5.00
WindyWillow    4.93
Stormchaser    4.90
Magda              4.82
Jemblow          4.80
January Avg    4.70
ARTzeman       4.60
RickM               4.45
SpringSun WD 4.40
Bolty                 4.30
Domma            4.20
Taylor1740      4.20
Snowshoe        4.20
Caz                    4.00
Wallaw              3.95
Bertwhistle       3.94
Sussex Snow    3.90
Frank H              3.85
Ally Pally            3.60
Lanky                  3.52
Col                      3.51
GezM                  3.35
Dingle Rob         3.30
Saint Snow        3.30
Redmoons         3.24 
Hungry Tiger     3.00
Scillydave          2.95
Jerry                   2.85
Norseman         2.80
Grandad             2.80
Kendalian          2.70
Dickieboy68      2.68



Currently living at roughly 65m asl North of Cowbridge in the Vale of Glamorgan.

Formerly of, Birdlip, highest village in the Cotswolds and snow heaven in winter; Hawkinge in Kent - roof of the South downs and Isles of Scilly, paradise in the UK.
Gavin D
02 January 2025 13:08:19
Hadley
8.3 to the 1st

4.4c above the 61 to 90 average
3.6c above the 91 to 20 average
Stormchaser
02 January 2025 16:37:24
Now that's an interesting spread of estimates!
I was tempted to go for a colder than average month but was unable to ignore that guidance for the 2nd half of the month is very keen on a positive NAO pattern taking hold with high pressure setting up over western mainland Europe (...again).
However, if we see some really cold nights over lying snow in the CET zone next week, then even if such a mild pattern establishes for the 2nd half of Jan, that might not be enough to bring the CET back above average.
If the pattern never takes hold to begin with, well, I'll be looking a bit daft I suppose 😄























































































Polar Westerly5.00
WindyWillow4.93
Stormchaser4.90
Magda4.82
Jemblow4.80
January Average4.70
ARTzeman4.60
RickM4.45
SpringSunWinterDread4.40
Bolty4.30
Taylor17404.20
Snowshoe4.20
Caz4.00
Wallaw3.95
Bertwhistle3.94
Sussex Snow3.90
Frank H3.85
Ally Pally3.60
Lanky3.52
Col3.51
GezM3.35
Dingle Rob3.30
Saint Snow3.30
Redmoons3.24
Hungry Tiger3.00
Scillydave2.95
Jerry2.85
Grandad2.80
Kendalian

Dickiboy68
2.70

2.68


Tabulation of the day? Thought it'd take less than a minute... nope!

Wait, why's the software added an enormous break above it plus merged the final two rows? 🤨🙄
If you have any problems or queries relating to TWO you can Email [email protected]

https://twitter.com/peacockreports 
2023's Homeland Extremes:
T-Max: 30.2°C 9th Sep (...!) | T-Min: -7.1°C 22nd & 23rd Jan | Wettest Day: 25.9mm 2nd Nov | Ice Days: 1 (2nd Dec -1.3°C in freezing fog)
Keep Calm and Forecast On
Dickieboy68
02 January 2025 18:44:06
Yes perhaps merging the bottom two rows is correct after all.... if you add our two values together, you are probably not too wrong ... can't believe I've gone lowest 😔 😞 
Cheers everyone- Dickieboy
Dickieboy - In the deep mid-Wiltshire
Formerly Guest (16) since 2004
rickm
03 January 2025 08:48:02
Not that much of a spread in the predictions really for what is probably the most difficult month to call for a long time.
ARTzeman
03 January 2025 10:33:20
IMANSF143      2.4c       Nicks'1BATH75      2.1c
Metcheck         3.66c       Anomaly      2.1c
Netweather      4.31c       Anomaly      0.12c
Peasedown St John     1.96c   Anomaly  -2.64c.....




Some people walk in the rain.
Others just get wet.
I Just Blow my horn or trumpet
Gavin D
03 January 2025 13:05:50
Hadley
4.7 to the 2nd

0.9c above the 61 to 90 average
0.1c above the 91 to 20 average
Stormchaser
03 January 2025 19:17:41

Not that much of a spread in the predictions really for what is probably the most difficult month to call for a long time.

Originally Posted by: rickm 


Indeed, it's the concentration of the spread on values below the long-term average that I find interesting. This country's weather has a real habit of not starting out as it means to go on, but on the other hand, there are now signs that a 'surface cold' setup could sustain even past the midpoint of January, so I'm starting to wonder if I should have been in the below average camp.

Then again, we're only 3 days in, a long way to go yet!
If you have any problems or queries relating to TWO you can Email [email protected]

https://twitter.com/peacockreports 
2023's Homeland Extremes:
T-Max: 30.2°C 9th Sep (...!) | T-Min: -7.1°C 22nd & 23rd Jan | Wettest Day: 25.9mm 2nd Nov | Ice Days: 1 (2nd Dec -1.3°C in freezing fog)
Keep Calm and Forecast On
ARTzeman
04 January 2025 11:49:38
IMANSF143       2.4c      Nicks1BATH75    1.7c
Metchcheck       2.92c     Anomaly       -1.23c
[color=var(--bs-body-color)][font=system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", "Noto Sans", "Liberation Sans", Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji"]Netweather        3.04c    Anomaly        -1.7c[/font][/color]
[color=var(--bs-body-color)][font=system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", "Noto Sans", "Liberation Sans", Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji"]Peasedown St John  1.6c  Anomaly    -3.1c....   [/font][/color]




Some people walk in the rain.
Others just get wet.
I Just Blow my horn or trumpet

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