January 2021 C.E.T. and EWP forecast contests

[booferking]

2.1c 74mm

[noname_weather]

3c and 68mm.

 

The good thing is that I am afraid I will be wrong and January will end up cooler than 3c, which is a win anyway.

[Summer Sun]

2.9c for me please

[Kentish Man]

2.0C thanks. Happy New Year to all!

[stewfox]

On 20/12/2020 at 09:20, stewfox said:

3.9c 65mm

Can I amend to 3c 75mm

[February1978]

2.7c and 72mm ..... and happy if it's below that....

[Midlands Ice Age]

Some very cold ones in..

Think the cold will set in, with frosty nights later dragging the CET down to  a very cold 1.2C. (originally was going for -1,2C), but we are seeing a very high risk/reward month with a bit of warmth trying to sneak in at times..

Hence 90mms of mainly snow to back it up.

MIA

Edited December 31, 2020 by Midlands Ice Age

[Roger J Smith]

Forecast -- CET +1.4, EWP 66.3

Here for your amusement and amazement is the complete list of Januaries that managed to run a CET of 1.5 or lower to the 16th since 1772 (and how they finished up, that's the question I am pondering because I could see the first half being slightly negative to perhaps +1.5, what's likely to happen to the block beyond that?)

If you wish to comment on this, maybe hold off until later to avoid further disruption of the flow of forecasts. I am going to post a forecast table a bit later than usual (one thing I can confidently predict) since I haven't even started into it yet. Only 3:30 p.m. 31st here anyway. 

By the way, some forecasts here are lower than the all-time coldest January of 1795 (-3.1), the experience of Dec 2010 shows that you can come close to an all-time record low, but going below it seems a bit of a stretch. 

 

 COLD STARTS to JANUARY (below 0.0 left, 0.1 to 1.5 right)

Year _____ CET to 16th ____ End Jan ______________ Year ____ CET to 16th ____ End Jan

1814 _____ -3.7 _____________ -2.9 ___________________ 1895 _____ 0.1 ___________ 0.2 (+1.0 25th, severe cold Feb)

1820 _____ -3.4 _____________ -0.3 ___________________ 1987 _____ 0.1 ___________ 0.8 (min -0.1 18th)

1795 _____ -2.6 _____________ -3.1 ___________________ 1811 _____ 0.3 ___________ 1.2 

1789 _____ -1.8 _____________+1.5 ___________________ 1830 _____ 0.3 ___________-0.2

1963 _____ -1.6 _____________ -2.1 ___________________ 1776 _____ 0.4 ___________-1.6 

1780 _____ -1.5 _____________ -0.9 ___________________ 1823 _____ 0.4 ___________-0.1

1802 _____ -1.4 _____________+1.6 ___________________ 1959 _____ 0.4 ___________ 1.6

1838 _____ -1.4 _____________ -1.5 ___________________1794 _____ 0.5 ___________ 1.8

1861 _____ -1.2 _____________+1.7 ___________________ 1784 _____ 0.6 ___________-0.6

1826 _____ -1.1 _____________+0.4 ___________________ 1871 _____ 0.7 ___________ 0.5

_____________________________________________________ 1792 _____ 0.7 ___________ 2.3

_____________________________________________________ 1799 _____ 0.8 ___________ 1.7

1867 _____ -0.9 _____________+1.2 ___________________ 1929 _____ 0.8 ___________ 1.3 (very cold Feb)

1893 _____ -0.9 _____________+2.2 ___________________ 1815 _____ 0.9 ___________ 0.3

1850 _____ -0.6 _____________+0.7 ___________________ 1854 _____ 0.9 ___________ 3.6

1879 _____ -0.6 _____________ -0.7 ___________________ 1892 _____ 0.9 ___________ 2.3

1891 _____ -0.5 _____________+1.3 ___________________ 1918 _____ 0.9 ___________ 3.8

1985 _____ -0.5 _____________+0.8 ___________________ 1778 _____ 1.0 ___________ 1.9

2010 _____ -0.5 _____________+1.4 ___________________ 1786 _____ 1.0 ___________ 2.7

1841 _____ -0.4 _____________+1.1 ___________________ 1997 _____ 1.1 ___________ 2.5

1982 _____ -0.4 _____________+2.6 ___________________ 1779 _____ 1.2 ___________ 2.9 (uh oh, warmest Feb followed)

1881 _____ -0.3 _____________ -1.5 ___________________ 1831 _____ 1.2 ___________ 1.6

1940 _____ -0.2 _____________ -1.4___________________ 1908 _____ 1.3 ___________ 2.5

1864 _____ -0.1 _____________+2.4 ___________________ 1955 _____ 1.3 ___________ 2.6

1887 _____ -0.1 _____________+2.4___________________ 1833 _____ 1.4 ___________ 1.2

1941 _____ -0.1 _____________ +0.5 __________________ 1876 _____ 1.4 ___________ 3.2

1979 _____ -0.1 _____________ -0.4 ___________________1777 _____ 1.5 ___________ 1.9

1774 _____ -0.1 _____________+0.6 ___________________ 1829 _____ 1.5 ___________ 0.3 (-0.2 25th)

1842 ______0.0 _____________+0.6 ___________________ 1980 _____ 1.5 ___________ 2.3

1892 _____+0.1 _____________+2.3 ___________________ 1942 _____ 1.6 ___________ 0.9

____________________________________________________________________________________

avg ______ -0.8 _____________ +0.4 ____________________ avg*_____ +1.1 _________ +1.6

________________________________________ * avg second set incl 1942,45, 2009

ANALYSIS: This is about one quarter of the total data set of daily interval means, so about a 1 in 8 chance

of any month falling into either group. The colder half of them rather predictably warm up by an average of

1.2 deg. The coldest outcome which was warmer than 1.5 on 16th is 1880 (0.9) which fell from 2.7 on 16th.

So otherwise every sub 1.0 January (since 1772) started out with a first half below 1.6 C.  (1942 started 1.6

and fell to 0.9 also). ... The less extreme half of the data set also warm slightly on average. However the rise

is less than half that seen in the colder half, suggesting that these less extreme cases might be almost as likely

to fall as to gain after mid-month. My guess is that these are similar in structure but the majority were snow

free a lot of the time, accounting for a higher average temperature. So if one of these marginal cases gets 

snow cover mid-month it could fall further. Jan 1881 fell quite steadily after a rather mild first week, also 

Jan 1776 did not start out extremely cold (but ended up that way). 

______________________________________________________________________________________

Jan 2009 was +1.7 to +3.0 for this time frame, given the recent climate warming it probably belongs in the data set. 

One case that was filtered out but might be similar is Jan 1945 which started moderately cold, warmed to 1.8 on 16th, 2.2 by 19th, then plunged to 0.4.

Famous cold Januaries (1684, 1740) from before daily data set have a reputation for being uniformly cold throughout, in the -2 to -3 range anyway.

Jan 1709 might have been colder in first half than second half, so it belongs in the top ten of cold starts probably.

Jan 1947 was still at +4.2 on 16th and ended +2.2. (not really similar to projections for first half of this month)

However that January only stayed cold at first for two days, so the evolution is a bit faster perhaps. 

My forecast philosophy is that the coming month will more likely resemble the weaker cases here, but that doesn't rule out severe cold near the end or into February. (note table edits after deadline no forecast edits)

Edited January 1, 2021 by Roger J Smith

[Duncan McAlister]

2.1 for me please and a dry 75mm for me, please. Happy New Year!

[Norrance]

Only very slightly late. 2.9C and 85 mms please.

[2010cold]

Sorry I'm late, it's only the first contest I've been late for.

2.4*c and 70.4mm please.   

[Roger J Smith]

 

 

Table of forecasts -- January 2021

(Numbers in brackets refer to the order of entry. You can still enter these contests until end of 3rd of January, with increasing late penalties). 

CET _ EWP _ FORECASTER ___________________________ CET _ EWP _ FORECASTER _____________________

9.5 _ ------ _ Lettucing Gutted ( 04 ) __________________ 2.7 _ 72.0 _ February1978 ( 69 ) ______________________

6.0 _ 43.0 _ syed2878 ( 20 )  _________________________2.6 _ ------ _ Man with Beard ( 38 ) ___________________ 

5.6 _ 64.0 _ weather26 ( 06 ) ________________________ 2.5 _ 65.0 _ The PIT ( 26 ) ____________________________ 

5.1 _103.0_ virtualsphere ( 12 ) ______________________2.4 _ ------ _ Quicksilver1989 ( 32 ) ___________________ 

4.7 _ 94.2 _ 1991-2020 average  _____________________ 2.4 _ 80.0 _ Feb1991Blizzard ( 63, 14.5 ) _____________

4.6 _ 35.0 _ I Remember Atlantic 252 ( 08 ) __________ 2.4 _ 70.4 _ 2010cold (L1-2) __________________________

4.4 _110.0_ Relativistic ( 55 ) ________________________ 2.3 _ 55.0 _ sundog ( 31 ) ____________________________ 

4.4 _ 93.0 _ 1991-2020 average ______________________ 2.2 _ 65.0 _ seaside60 ( 51 ) _________________________

4.2 _151.3_ Polar Gael ( 05 ) _________________________ 2.2 _ 73.0 _ Great Plum ( 62 ) ________________________ 

4.2 _ 50.0 _ DiagonalRedLine ( 09 ) __________________ 2.1 _ ------ _ Typhoon John ( 11 ) ________________

4.2 _ ------ _ Froze were the Days (L1-3) ______________ 2.1 _ 62.0 _ BornFromTheVoid ( 23 ) ___________

4.2 _115.0_ DAVID SNOW (L1-5) _____________________ 2.1 _ 74.0 _ booferking ( 64 ) __________________

4.1 _100.0_ DR(S)NO ( 58 ) __________________________ 2.1 _ 75.0 _ Duncan McAlister ( 72 ) ____________

4.0 _130.0_ moffat ( 07 ) ____________________________ 2.1 _ 75.0 _ Blast from the Past (L1-4) __________

4.0 _ 40.0 _ Leo97t ( 42 ) _____________________________2.0 _ 89.0 _ snowray ( 40 ) _______________________

3.9 _ 65.0 _ pegg24 ( 10 ) ____________________________ 2.0 _ ------ _ Kentish Man ( 67 ) ___________________

3.9 _ 59.0 _ prolongedSnowLover ( 46 ) ______________1.8 _ 60.0 _ Earthshine ( 14 ) ____________________

3.8 _ 80.0 _ Federico ( 25 ) ___________________________ 1.8 _ 56.3 _ Dog Toffee ( 24, 16.5 ) _______________

3.8 _ 97.0 _ Reef ( 50 ) ________________________________1.7 _ 88.4 _ Kirkcaldy Weather ( 16 ) _____________

3.7 _ 78.0 _ bobd29 ( 01 ) ____________________________ 1.5 _ 75.0 _ Godber 1 ( 59 ) ______________________

3.7 _ 60.0 _ summer blizzard ( 34 ) ___________________1.4 _ 66.3 _ Roger J Smith ( 71 ) __________________

3.5 _ 85.0 _ Jeff C ( 02 ) _______________________________1.3 _ 66.0 _ Neil N ( 18 ) _________________________

3.5 _ 64.0 _ stargazer ( 36 ) __________________________ 1.3 _ 73.0 _ moorlander ( 53 ) ___________________

3.5 _ 57.0 _ SteveB ( 45 ) _____________________________1.3 _ ------ _ Steve Murr (SMU) (L1-6) _____________

3.5 _ 65.0 _ J10 ( 60 ) _________________________________1.2 _ 65.0 _ Let It Snow! ( 03 ) ___________________

3.3 _ ------ _ damianslaw ( 52 ) _______________________ 1.2 _150.0_ John88B ( 21 ) _______________________

3.1 _105.0_ shillitocettwo ( 29 ) ______________________1.2 _ 50.0 _ daniel* ( 33 ) _________________________

3.1 _ 55.0 _ General Cluster ( 43, 33.5 ) ______________ 1.2 _ 90.0 _ Midlands Ice Age ( 70 ) _______________

3.0 _ 30.0 _ B87 ( 47 ) ________________________________1.1 _ 61.0 _ jonboy ( 37 ) _________________________

3.0 _ 68.0 _ noname_weather ( 65 ) __________________0.9 _ 68.0 _ Emmett Garland ( 48 ) _______________

3.0 _ 75.0 _ stewfox ( 68 ) ____________________________0.8 _ 56.0 _ Walsall Wood Snow ( 44 ) ___________

2.9 _ 35.0 _ Frigid ( 15 ) _______________________________0.7 _ 25.0 _ Captain Shortwave ( 13 ) ___________

2.9 _ ------ _ dancerwithwings ( 28 ) ___________________0.7 _ 55.0 _ Paul T ( 27 ) _________________________

2.9 _ 77.0 _ Timmytour ( 39 ) ________________________0.6 _ 78.0 _ Stationary Front ( 17 ) _______________

2.9 _ 70.0 _ Mr Maunder ( 41 ) ______________________ 0.4 _ 97.0 _ cymro ( 35 ) _______________________

2.9 _ 70.0 _ summer18 ( 54 ) ______________________ --1.4 _115.0_ SLEETY ( 30 ) ________________________

2.9 _ 65.0 _ Don ( 57 ) _____________________________  --3.5 _300.0_ Deep Snow Please ( 19 ) _____________

2.9 _ 75.0 _ Mulzy ( 61 ) ____________________________ --4.7 _ 25.0 _ Thundershine ( 22 ) __________________

2.9 _ ------ _ Summer Sun ( 66 ) ______________________

2.9 _ 85.0 _ Norrance (L1-1) _________________________

2.8 _ 63.0 _ davehsug ( 49 ) __________________________

2.8 _ 62.0 _ weather-history ( 56 ) ____________________

2.8 _ 68.0 _ consensus _______________________________

72 on-time forecasts, plus six so far that were one day late,  78 in total ... consensus 2.8 (median).

This is probably one of the coldest set of forecasts we've had in the contest in quite some time. 

==================================================================================

EWP forecasts (in order)

300_DSP ... 151.3_PG ... 150_John ... 130 moff ...115_SLE,DS^ ... 110_rel ... 105_Shil ... 103_virt ... 100_DR(S) ... 97_cym,Reef

... 94.2 (91-20) ... 93 (81-10) ... 90_MIA ... 89_snow ... 88.4_KW ... 85_Jeff,norr^ ... 80_Feb91,fed ... 78_bob,SF ... 77_tim

... 75_godb,Mul,stew,Dunc,BFTP^ ... 74_boof ... 73_moor,GP ... 72_Feb78 ... 70.4_2010cold^... 70_MrM,sum18

... 68_EG,non ... 66.3_RJS ... 66_NN ... 65_LIS,pegg,PIT,sea,Don,J10 ... 64_wx26,star ... 63 dave ... 62_BFTV,wx-his

... 61_jon ... 60_earth,sb ... 59_pSL ... 57_Ste ... 56.3 DT ... 56_WWS ... 55_PaulT,sun,GC ... 50_DRL,dan ... 43_syed

... 40_Leo ... 35_IRem,Frig ... 30_B87 ... 25_Capt,thun

64 on time forecasts, plus four so far marked one day late (^) consensus 68.0 mm. 

=================================================================

(note -- will continue to use 1981-2010 as the reference "normal" for contests, until we have official 1991-2020 numbers; mine are unofficial and this January CET version is very close to a rounding point, official version could be 4.6 or 4.7 C (metoffice average their mean max and mean min, I just average monthly CET values, can be slightly higher as a result, 1991-2020 came out at 4.66). The EWP averages are less problematic. The 1991-2020 average will be used to determine correct side of normal although it affects no forecasts yet submitted (first one below it is 1981-2010). 

Edited January 15, 2021 by Roger J Smith
noticed a username change for Steve Murr to SMU _ thought at first I had missed an entry

[Froze were the Days]

Dam! late...I'll go for 4.2c please, cold start becoming milder before mid-month

[BLAST FROM THE PAST]

Late!  2.1c

75mm

 

BFTP

Edited January 1, 2021 by BLAST FROM THE PAST

[DAVID SNOW]

Even later 4.2

115mm.

[Man With Beard]

Not often I'll go for a figure 1.5C below average and still be thinking I've gone too high!

[SMU]

Late

 

1.3c Please

[Roger J Smith]

1981-2010 CET Daily averages for January, with daily extremes and running CET extremes (1772-2020)

... the extremes are 1772-2020 ...[] below are for 1981-2010 []... these are again 1772-2020

DATE __ MAX (year) ____ MIN (year) ___ CET mean, cum  __ extremes of running CET 01-date

01 Jan ... 10.8 (1851) ... ... -5.9 (1820) ... ... 4.5 ... ... 4.5 ..... ..... 10.8 (1851) ... -5.9 (1820)
02 Jan ... 10.4 (1948) ... ... -6.1 (1786) ... ... 4.6 ... ... 4.5 ..... ..... 10.1 (1851) ... -5.9 (1786)
03 Jan ... 11.6 (1932) ... ... -7.7 (1795) ... ... 4.2 ... ... 4.4 ..... ....... 9.7 (1917) ... -6.5 (1786)
04 Jan ... 10.5 (1948) ... ... -9.3 (1867) ... ... 4.2 ... ... 4.4 ..... ....... 9.7 (1916) ... -6.0 (1795)
05 Jan ... 11.4 (1957) ... ... -6.5 (1789) ... ... 4.6 ... ... 4.4 ..... ....... 9.3 (1916) ... -5.3 (1795)

06 Jan ... 10.3 (1898) ... ... -6.9 (1894) ... ... 4.6 ... ... 4.5 .... ....... 9.2 (1916) ... -4.6 (1795)
07 Jan ... 10.3 (1890) ... ... -7.7 (1841) ... ... 3.4 ... ... 4.3 ..... ....... 9.2 (1916) ... -3.9 (1795)
08 Jan ..... 9.9 (1858) ... ... -9.2 (1841) ... ... 4.0 ... ... 4.3 ..... ....... 8.8 (1992) ... -3.4 (1864)

09 Jan ... 10.7 (1998) ... ... -5.0 (1841) ... ... 4.3 ... ... 4.3 ..... ....... 8.4 (1916) ... -2.8 (1795, 1864)
10 Jan ... 11.1 (1921) ... ... -6.7 (1814) ... ... 4.5 ... ... 4.3 ..... ....... 8.3 (1916) ... -3.0 (1814)

11 Jan ... 10.1 (1990) ... ... -5.5 (1838) ... ... 4.4 ... ... 4.3 ..... ....... 8.3 (1916) ... -3.2 (1814)
12 Jan ..... 9.9 (1976, 2007) .. -7.7 (1987) ....4.4 ... ... 4.3 ..... ....... 8.2 (2007) ... -3.4 (1814)
13 Jan ... 10.0 (1796, 1873) .. -6.6 (1987) ....4.6 ... ... 4.3 ..... ....... 8.4 (2007) ... -3.4 (1814)
14 Jan ... 10.2 (2011) ... ... -7.6 (1982) ... ... 4.4 ... ... 4.4 ..... ....... 8.2 (2007) ... -3.6 (1814)
15 Jan ... 10.3 (1804) ... ... -8.5 (1820) ... ... 4.6 ... ... 4.4 ..... ....... 8.1 (2007) ... -3.7 (1814)

16 Jan ... 10.8 (1990) ... ... -7.7 (1881) ... ... 4.8 ... ... 4.4 ..... ....... 8.1 (2007) ... -3.7 (1814)
17 Jan ... 10.2 (1908) ... ... -6.2 (1881) ... ... 4.6 ... ... 4.4 ..... ....... 8.2 (2007) ... -3.7 (1814)
18 Jan ... 10.0 (1828) ... ... -6.1 (1891) ... ... 4.5 ... ... 4.4 ..... ....... 8.2 (2007) ... -3.6 (1814)
19 Jan ... 11.1 (1930) ... ... -8.9 (1823) ... ... 5.1 ... ... 4.4 ..... ....... 8.3 (2007) ... -3.5 (1814)
20 Jan ... 11.2 (2008) ... ...-11.9 (1838) ... ... 5.1 ... ... 4.5 ..... ....... 8.3 (2007) ... -3.4 (1814)

21 Jan ... 10.8 (1796, 1898)..-8.1 (1881) ... ...5.1 ... ... 4.5 ..... ..... 8.2 (2007) ... -3.5 (1814)
22 Jan ... 10.3 (1878) ... ... -6.4 (1881) ... ... 4.4 ... ... 4.5 ..... ....... 8.0 (2007) ... -3.6 (1814)
23 Jan ... 11.6 (1834) ... ... -8.4 (1963) ... ... 4.4 ... ... 4.5 ..... ....... 7.7 (1976, 2007) ... -3.6 (1814)
24 Jan ... 10.6 (1782) ... ... -8.2 (1963) ... ... 4.4 ... ... 4.5 ..... ....... 7.6 (1916) ... -3.6 (1814)
25 Jan ... 11.6 (2016) ... ... -8.9 (1795) ... ... 4.1 ... ... 4.5 ..... ....... 7.5 (1796, 1916) .-3.6 (1795, 1814)

26 Jan ... 10.0 (1834) ... ... -7.6 (1945) ... ... 4.1 ... ... 4.5 ..... ....... 7.6 (1916) ... -3.6 (1795)
27 Jan ... 10.5 (2016) ... ... -6.5 (1776) ... ... 4.2 ... ... 4.4 ..... ....... 7.6 (1916) ... -3.3 (1814)
28 Jan ..... 9.8 (1944) ... ... -6.3 (1776) ... ... 4.3 ... ... 4.4 ..... ....... 7.6 (1916) ... -3.2 (1814)
29 Jan ... 10.4 (1854) ... ... -6.8 (1776) ... ... 4.6 ... ... 4.4 ..... ....... 7.6 (1916) ... -3.1 (1795, 1814)
30 Jan ... 10.2 (2000) ... ... -7.5 (1776) ... ... 4.2 ... ... 4.4 ..... ....... 7.6 (1916) ... -3.1 (1795)
31 Jan ... 10.9 (1868) ... ... -7.2 (1776) ... ... 4.5 ... ... 4.4 ..... ....... 7.5 (1916) ... -3.1 (1795)

_____________________________________________________________________________

As a measure of how cold Jan 1963 was, the running mean to 24th, 25th and 26th was -2.7 C. 

1834 almost caught the leaders by 28th at 7.5 C, finished on 7.1. ... 1814 fell back only to -2.9 C.

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

(tracking daily CET 1991-2020) ... not sure if Summer Sun will want to use these or not, but here

they are, hot off the presses, 1991-2020 CET daily averages and running means for each day. 

First number is the daily mean, second is the running average to that date. 

 1._ 4.7 _ 4.7 _____ 11._  5.0 _ 4.8 ______ 21.  4.3 _ 4.8 _______ 31._ 4.4 _ 4.7** 

 2._ 4.5 _ 4.6 _____ 12._  5.2 _ 4.8 ______ 22.  3.9 _ 4.8 _______ 

 3._ 4.2 _ 4.5 _____ 13._  5.4 _ 4.9 ______ 23.  4.0 _ 4.8 _______ 

 4._ 4.2 _ 4.4 _____ 14._  5.2 _ 4.9 ______ 24.  4.4 _ 4.7 _______ 

 5._ 4.6 _ 4.4 _____ 15._  5.1 _ 4.9 ______ 25.  4.5 _ 4.7 _______ 

 6._ 5.0 _ 4.5 _____ 16._  5.1 _ 4.9 ______ 26.  4.4 _ 4.7 _______ 

 7._ 4.7 _ 4.6 _____ 17._  4.7 _ 4.9 ______ 27.  4.5 _ 4.7 _______ 

 8._ 5.4 _ 4.7 _____ 18._  4.5 _ 4.9 ______ 28.  4.2 _ 4.7 _______ 

 9._ 5.1 _ 4.7 _____ 19._  4.8 _ 4.9 ______ 29.  4.4 _ 4.7 _______ 

10._ 5.1 _ 4.8 _____ 20._  4.6 _ 4.9 ______ 30.  4.1 _ 4.7 _______ 

The 1991-2020 met office average for January may be 4.6, my average of all daily data is 4.657

and they use a slightly different method (average of mean max and mean min) whereas my

method is to average 30 CET monthly values (or these daily values, same result). 

- In terms of when 1991-2020 normals will be available officially, on the American Weather Forum where I posed the same question, I was told that the WMO meets in late May of 2021 to determine the new normals and then individual countries decide what 30-year periods will be official reference points. This is already different in practice, the U.S. weather stations that I consult regularly for contest and research work have given anomalies relative to 1981-2010 since 2012. The met office uses 1961-90, will be interesting to see if they move to 1971-2000 or 1981-2010 at any point this year. 

[Summer Sun]

0.5c to the 1st

3.0c below the 61 to 90 average
4.0c below the 81 to 10 average

___________________________

Current high this month 0.5c on the 1st
Current low this month 0.5c on the 1st

[Weather-history]

5 minutes ago, Summer Sun said:

0.5c to the 1st

3.0c below the 61 to 90 average
4.0c below the 81 to 10 average

___________________________

Current high this month 0.5c on the 1st
Current low this month 0.5c on the 1st

Coldest New Year's Day since 2010 

[summer blizzard]

What was the coldest opening third since 2010 and was the value for 1st-10th.

[Roger J Smith]

CET values for 1st-10th Jan since 2009 (in order)

Jan 2010 __--1.90 (-1.9) 

Jan 2009 __--0.37 (-0.4)

Jan 2011 __ 2.96 (3.0)

Jan 2019 __ 4.24 (4.2)

Jan 2018 __ 4.65 (4.7)

Jan 2017 __ 4.75 (4.8)

Jan 2016 __ 6.04 (6.0)

Jan 2015 __ 6.29 (6.3)

Jan 2014 __ 6.86 (6.9)

Jan 2013 __ 6.91 (6.9)

Jan 2020 __ 7.13 (7.1)

Jan 2012 __ 7.42 (7.4)

______________________________________________________

so the answer is 2011, followed by 2019, 18 and 17.

The cold start to Jan 2010 ranks 9th coldest of the daily data interval (1772-2020) and was only beaten barely by 1841 (-1.95), 1893 (-1.97) and 1861 (-2.00), then also 1864 (-2.09), 1789 (-2.19), 1820 (-2.48) , 1795 (-2.59),  and 1814 (-2.97).

Both 1963 and 1979 were not as cold by 10th (-0.6 and -0.4). 

So the first ten days of January 2010 were the coldest since 1893. 

 

 

[Summer Sun]

0.5c to the 2nd

3.0c below the 61 to 90 average
4.0c below the 81 to 10 average

___________________________

Current high this month 0.5c on the 1st & 2nd
Current low this month 0.5c on the 1st & 2nd

[Man With Beard]

2 hours ago, Summer Sun said:

0.5c to the 2nd

3.0c below the 61 to 90 average
4.0c below the 81 to 10 average

___________________________

Current high this month 0.5c on the 1st & 2nd
Current low this month 0.5c on the 1st & 2nd

I doubt this will go above 2C until at least mid month. It will be a long road to get back to average. If the SSW ushers in another cold shot later in the month, it won't get anywhere near average.

[summer blizzard]

That 2013-2019 run is an interesting little quirk and it's fair to say that we have a good shot of slotting into third in that list.

2 hours ago, Man With Beard said:

I doubt this will go above 2C until at least mid month. It will be a long road to get back to average. If the SSW ushers in another cold shot later in the month, it won't get anywhere near average.

Given that the peak impact in the troposphere probably won't occur until the final third of January if zonal winds are reversed as long as currently forecast i am a tad concerned that i may have woefully overestimated. This cold start makes the potential CET very, very interesting.