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Roger J Smith

December 2016 C.E.T. forecasts -- start of 2016-17 competition year

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CET averages and extremes

 

13.1 ... warmest daily mean, 19th 2015

12.9 ... previous warmest daily mean, 12th 1994

9.7 ... warmest December 2015
8.1 ... tied second warmest Decembers 1934 and 1974
7.7 ... fourth warmest December 1852

7.6 ... fifth warmest December 1733

 

6.3 ... Dec 2013

5.2 ... Dec 2014

5.1 ... average for 1971-2000*

5.0 ... average for 1986-2015

4.9 ... average for 2001-2015

4.8 ... Dec 2012
4.7 ... average for 1961-90
4.6 ... average for 1981-2010, also 1901-2000
4.1 ... average for 1659-2015
4.0 ... average for 1801-1900
3.9 ... average for 1701-1800
3.4 ... average for 1659-1700

--0.4 ... tied fourth coldest 1788 and 1796
--0.5 ... third coldest 1676
--0.7 ... second coldest 2010
--0.8 ... coldest December 1890

-10.8 ... lowest daily mean 25th 1796

_______________________________________________

Enter your forecast before midnight on Wed 30 November, or take the increasing late penalties for entries 1-3 Dec.

*This is in fact the highest 30-year average for December in the CET series, and the only one that rounds to 5.1, from 5.06.

As you might expect, the Maunder period produced cold Decembers, the mean was as low as 3.2 (1665 to 1694). It then rose as high as 4.29 by 1709-38. There was a colder period than any in the Maunder; the lowest 30-year average was 3.09 from 1783 to 1812; rounded off 1784 to 1813 was equal.

The running mean climbed as high as 4.61 for 1823-52 before falling back to 3.48 for 1867-96. Decembers in the first third of the 20th century were generally a bit milder than the mid-century period, means as high as 4.73 were reached in 1893-1922 and 1907-36. The lowest since those peaks was 4.33 for 1923-52. The last time that the running mean was 4.5 was 1957 to 1986. The table above tracks the changes since then, but worth noting that the cold December of 2010 dropped the running mean from 4.84 to 4.63 but it then went back up to 4.82 for 1982 to 2011 as that period dropped the cold December of 1981 (mean 0.3). 

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I think I'll plump for 2.7c please.

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As I have mentioned in the past, no 5.9 which I find remarkable.

The climatic odds of recording a December above 9.0 before a 5.9 after decades of records must be very, very small.

Edited by Weather-history
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2.8°C

Thank you please!

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don't want Craig Evans winning again! 5.9C my 'guess'

dominated by the Atlantic, low after low, NW'lys behind systems but unlikely to see any snow in CET zone

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Would be nice to have a below average December for the first time in five years. 

 

4.5c. Anticyclonic with many chilly nights but some milder incursions, especially in the day. 

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4.0c please.

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55 minutes ago, I remember Atlantic 252 said:

don't want Craig Evans winning again! 5.9C my 'guess'

dominated by the Atlantic, low after low, NW'lys behind systems but unlikely to see any snow in CET zone

Not a chance Ian, Mr Evens will be around 9 degrees, again.

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I'll take a punt on 3.8C please...I might be relying on freezing fog, though?:D

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Sort of setup I expect for Dec, only early in month, but expecting PV to develop fully around its greenie home, maybe signs already on image, yes a 'cherry picked' chart, but we all do it!

gensnh-2-1-384.png

Edited by I remember Atlantic 252
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A remarkable statistic from last year's December was that the second half (16th-31st) saw a mean of 10.4C.

That's a whopping 1.8C up on the next warmest, 1987 (8.6C);

1.2C warmer than the warmest first half, 1898 (9.2C);

0.8C warmer than the warmest second half of November, 1994 (9.6C);

0.3C warmer than the warmest November, 1994 (10.1C);

Only 6 first halves of November have ever equalled or beaten it;

Only 5 first halves of April have ever equalled or beaten it.

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I'll go for 4.3°C. A changeable month with both mild and cold interludes. 

Edited by LetItSnow!
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12 hours ago, Weather-history said:

As I have mentioned in the past, no 5.9 which I find remarkable.

The climatic odds of recording a December above 9.0 before a 5.9 after decades of records must be very, very small.

I'm going for 5.9C......  2016 is the year that's delivering everything!

I think we are in for a special winter, but I don't think it will really get going until the  last week in Dec

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Morning all.  Hope you don't mind me joining in. Going for 3.1  with a white xmas thrown in as an added bonus 

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4.9c please.

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I'll take a guess with 2.8c. A similar setup to 1996 I think. It won't be nothing exceptional, but it will certainly have its wintry moments.

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On 11/19/2016 at 12:00, Weather-history said:

As I have mentioned in the past, no 5.9 which I find remarkable.

The climatic odds of recording a December above 9.0 before a 5.9 after decades of records must be very, very small.

 

There was only one 3.1 January (1832). That is quite odd given that the long-term average until 2016 was 3.2.  Another rather unexpected single is 11.2 in October. In this study it must be remembered that from 1659 to about 1710, almost all the values were multiples of 0.5.

This is interesting from the statistical point of view. Here is a list of the closest-to-long-term missing values of CET on both the warm and the cold sides of normal. The averages are for 1659 to 2016 except for this month and December which use 1659 to 2015. In a warming climate I suppose you could say there is an increasing chance of filling in the holes on the high side of average, and a decreasing chance of filling in holes on the low side. I have included all missing values out to the extremes. May has filled in every value below average to the extreme of 8.5 so the comparative value is 8.4. July has also filled in every value below average to the extreme of 13.4 so the comparative value is 13.3. 

 

Never recorded monthly CET values (between extremes)

 

MONTH _____ Low side of average _______________ 1659-present Average _____ High side of average

January _-2.7 to -2.2, -1.9,-1.8,-1.7,-1.3,-1.2,-1.1, -0.5 _________ 3.3 ______ 7.2, 7.4

February _ -1.5 to -1.2, -0.9,-0.8,-0.6 to -0.3, -0.1, 0.2, 0.3, 1.1, 1.3 __ 3.9 ____ 7.4, 7.6, 7.7, 7,8

March ___ 1.1, 1.3, 1.4, 1.5, 1.6, 1.7, 2.2, 2.4, 2.6 _____________ 5.3 ______ 8.0, 8.5, 8.6, 8.7, 8.8, 8.9

April ____________________ 4.8 to 5.1, 5.3, 5.6 ____________ 7.9 _____ 10.7, to 11.1, 11.3 to 11.7

May _________ no values missing therefore 8.4 ___________11.2 _____ 13.2, 14.0 to 15.0

June ___________________________11.6, 11.7 _________ 14.3 __ 16.3, 16.5, 16.7, 17.2, 17.4 to 17.9, 18.1

July _________ no values missing therefore 13.3 ________ 16.0 ____ 18.9 to 19.4, 19.6

August ____________________ 13.1, 13.2, 13.4 _______ 15.6 __ 17.7, 17.9, 18.4, 18.5, 18,8, 18,9, 19.1

September _____________________ 10.8, 10.9 _______13.3 __ 15.5, 15.8, 15.9, 16.1, 16.2, 16.4, 16.5, 16.7

October __________5.4 to 6,3, 6.6, 6.7, 6.8, 7.7 _______ 9.7 ____ 12.1, 12.2, 12.4, 13.2

November __________________ 2.4 to 2.7, 3.8 _______ 6.1 _____ 8.3, 8.8, 9.0, 9.7 to 10.0

December ___ -0.6, -0.4, -0.1, 0.0, 0.1, 0.2. 0.8, 0.9 ____ 4.1 ____ 5.9. 7.0, 7.1, 7.8 to 8.0, 8.2 to 9.6

____________________________________________________________________

These can best be compared by ranks. I have blended these but the cold side rankings are in italics so you can more easily compare the high and low side ... if second missing value is not top five, I mention its rank as well. A month would add one rank in this table each time that the second highest or lowest value was snatched away including consecutive values to the extreme as for example if December hit 0.8 and not 0.9. If this December were colder that would add one rank to the value waiting to be hit or if any more extreme value already established is tied..

The most extreme is the 5.9 for December, if it occurred this year, it would be the 54th warmest December. If that 11.2 had not happened in Oct 1706, it would be a missing 40th warmest. But if the 3.1 had not happened in Jan 1832, it would be a missing 149th coldest.

If February was 1.3, that would be 31st coldest. 1.1 would be 28th coldest. 0.3 or 0,2 would rank 11th.

The next October to hit 7.7 will be 27th coldest. However, it has not been that cold since 7.8 in 1992 (colder 1919).

If November hits 8.3 next year (because it likely won't this year) it would be 20th warmest. (8.8 10th warmest).

Also, the next November to hit 3.8 (assuming nothing colder in between) will be 20th coldest

If December hits 0.9 or 0.8, that would be 17th coldest (0.8 would then make 0.9 18th coldest).

Also the next January to hit --0.5 will be 17th coldest. Anything -1.3 to -1.1 would be 12th coldest (then -0.5 18th).

The next April to hit 5.6 (assuming nothing colder in between) would be 16th coldest, 5.3 would be fifth coldest.

If next June hits 16.3, that would be 15th warmest. (16.5 10th warmest)

... and if Oct hits 12.1 or 12.2, 15th warmest. 12.4 would be 13th warmest.

If next May hits 13.2, that would be 12th warmest. Also if August hits 17.7, that would be 12th warmest 

If next March hits 2.6 that would be 12th coldest. 

If next March hits 8.0, that would be 10th warmest. Also if September hits 15.5 that would be 10th warmest.

The next September to hit 10.9 or 10.8 would be 7th coldest (10.8 would move 10.9 to 8th coldest). (little optimism for this)

The next August to hit 13.4 would be 5th coldest (might take a glacial episode for this one).

If January hit 7.2 that would be 4th warmest, and if February hit 7.4, 3rd warmest. Also if April hits 10.7-11.1, 3rd warmest.

If July hits 18.9 to 19.4, that would be 3rd warmest. 

If any June ever manages 11.7 or 11.6, that would be 2nd coldest, 11.6 would move 11.7 to 3rd coldest.

If May or July hit the first unrecorded low value, that would be a new record (coldest).

Edited by Roger J Smith
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