Please pm your December prediction to me by midnight on 30th November.

Please try to meet the deadline.

I will post my own prediction directly onto the thread.

Some background information:

Average 1991 -20 = 4.8c

Warmest all time = 9.6c (2015) - Second warmest was way below at 8.1c (1934)

Coldest this century = -0.7c (2010)  -  1981 was 0.1c

Last 5 years:

2018 = 6.8c

2019 = 5.7c

2020 = 4.9c

2021 = 6.3c

2022 = 3.4c  (was only 0.5c at the 16th)

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If ECM is on the money tonight we'd be looking at a similar first half than last year. 

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I inadvertedly deleted a December CET prediction yesterday evening when I was deleting items from my inbox.
  Could whoever posted it please resend - there was only one.
Apologies for my carelessness.
Tip for JMM2005 - clear your inbox before setting up the new monthly CET thread

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Just stickied it for you Frank.   🙂 

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Always a tough month to predict and compete in with everyone getting a bit tactical and the emotion of wanting cold and snowy weather at Xmas kicking in !
A shame not to be in contention this time but wishing you all the best of luck !
Remember my win against Saint Snow a couple of years back... I knew he'd cold ramp and he knew I'd mild ramp , luckily for me we ended up with a mild borefest !
While last year of course the cold blindsided me , so many years of waiting for a decent December that I failed to anticipate one when it finally came 

Indeed, it's a very hard month to call because we're teetering right on the edge of being plunged into a longer-lasting cold pattern, or having the cold break down after the first week and ending up mild/Atlantic-dominated instead. It really is literally on a knife edge and the smallest possible adjustments could send it either way.

Personally I think we will see the cold break down with a return to mild for the time being, before we potentially see a return to colder conditions in the run-up to Christmas. I've sent my guess to reflect this.

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I'll go for 5.35c

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A tough one this is. I've gone for only slightly below average. 

I think the coldies will be disappointed. But i could be wrong.  🙂 

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December Predictions

A big spread in predictions but not much difference in the leaders' predictions.

sussex snow magnet 7.90
dingle rob                 7.10
redmoons                 6.45
Dickieboy68              6.10
lanky                         6.04
col                             6.03
snowshoe                 5.90
tierradelfuego           5.90
Gavin D                     5.90
windywillow              5.70
frank h                      5.35
scillydave                  5.30
caz                            5.20
sswd                         5.10
gezm                        5.05
hungry tiger             5.00
bolty                        5.00
artzeman                 4.85
stormchaser            4.61
rickm                       4.55
grandad                  4.40
kendalian                4.30
ap snowman           3.90
bertwhistle              3.77
jmm2005                3.70
taylor1740              3.20

At a quick glance its only possible for the outright winner to be one of the top 3 at November ( Bolty, Rickm, Grandad) or Dingle Rob.
Full analysis will follow.

 

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As far as I can see the outright 2023 CET competition winner will be as follows for the following possible December CET values :

6.85c and above - Dingle Rob winner

6.84c  - Dingle Rob and Bolty tied
            Bolty would win the tie break per GW's rules (they were both equal on best prediction in the year but Bolty's 2nd best was better)

4.57c to 6.83c - Bolty winner

4.50c to 4.56c  - Rickm winner

4.49c and below  - Grandad winner

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Surprised no one is really going out on a limb for cold given the models ATM

Of course I haven't either but still thought someone would bite !

Lowest guess is similar to last year and would still be the coldest since 2010 of course 

IMANSF22                  -2.3c                Nicks - 1BATH75             -2.1c
Metcheck                   -0.75c              Anomaly                          -5.74c
Netweather                -0.27c              Anomaly                          -5.38c
Peasedown st John    -2.65c              Anomaly                          -2.2c.

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Hadley

-0.5c to the 1st

5.1c below the 61 to 90 average
6.1c below the 81 to 10 average

May as well lay out my general musing for this month here so we can see how it fares:
- Cold opening 5-6 days
- Then generally mild until at least mid-month (CET climbs to at least a little above the 1991-2020 average)
- Return to colder weather as MJO-led forcing encourages westward shifting of high pressure initially over or just east of Scandinavia (CET dragged back down to the long-term average, then a little below).

That last stage is of course the least confident, though not as much so as would usually be the case, thanks to some strong cross-model support for the required MJO activity plus a weakened polar vortex. Most probable causes of the CET ending up well above my estimate are an unexpected stall in MJO progression, or the encroached blocking high happening to orientate in a way that holds temps up across the UK during that final stage.

All these events also greatly raise the chance of a sudden stratospheric warming event happening in 3-6 weeks time, but that's unlikely to have much, if any, bearing on this month's weather patterns hence the CET.

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IMANSF22                  -1.3c                  Nicks - 1Bath 75             -0.3c
Metcheck                   -0.50c                Anomaly                          -5.41c
Netweather                -0.78c                Anomaly                          -5.89c  
Peasedown St John    0.05c                 Anomaly                          -4.85c

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Hadley

-1.0c to the 2nd

5.5c below the 61 to 90 average
6.6c below the 81 to 10 average

Definitely the coldest start to December since 2010.   🙂 

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Yesterday's CET was the coldest this year (so far)

yes those are significant anomalies even if it is just the first few days. There are some really mild CET predictions that would need some really mild weather for the entire remainder of the month to get close.

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IMANSF22                  -0.4c               Nicks-1BATH 75             2.1c
Metcheck                    0.88c              Anomaly                        -4.11c
Netweather                 0.79c              Anomaly                       -4.32c
Peasedown St John     2.45c              Anomaly                       -2.4c.  

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Hadley

0.1c to the 3rd

4.4c below the 61 to 90 average
5.6c below the 81 to 10 average

IMANSF22                  0.8c                Nicks-1BATH 75          3.3c
Metcheck                    1.79c              Anomaly                     -3.21c
 Netweather                1.96c              Anomaly                     -3.15c
Peasedown St John     2.61c              Anomaly                     -2.24.    

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Hadley

1.3c to the 4th

3.2c below the 61 to 90 average
4.4c below the 81 to 10 average

IMANSF22                    0.3c                 Nicks 1Bath 75          2.0c
Metcheck                     1.87c               Anomaly                    -3.12c
Netweather                  2.35c               Anomaly                    -2.36c
Peasedown St John      2.3c                 Anomaly                    -2.55c.

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Hadley

2.0c to the 5th

2.5c below the 61 to 90 average
3.8c below the 81 to 10 average