December 2023 C.E.T. and EWP forecast contests -- start of 2023-24 contest year -- all welcome

[Dancerwithwings]

10 minutes ago, Don said:

Thinking my 5.4C guess 'could' be on shaky ground!

My 4.9c is… well at least we’ve got another 11 guesses to get it right Don

Edited December 12, 2023 by Dancerwithwings

[Don]

3 minutes ago, Dancerwithwings said:

My 4.9c is… well at least we’ve got another 11 guesses to get right Don

Yep, early days (like winter!) as they say!  

[Dancerwithwings]

Just now, Don said:

Yep, early days (like winter!) as they say!  

Lmao …”Like Winter”  to get that right it’s 72h 

[Don]

1 minute ago, Dancerwithwings said:

Lmao …”Like Winter”  to get that right it’s 72h 

I meant it's 'early days' for winter in that although it's not great at the moment, there's plenty of time for it to redeem itself!  

[Roger J Smith]

25 minutes ago, Dancerwithwings said:

My 4.9c is… well at least we’ve got another 11 guesses to get it right Don

(Don said 5.4 not looking good now ...)

These may both be okay, in particular 5.4 does not look overly high, an average of 6.5 now to end will give an outcome near 5.5 and there are enough colder days in the mix to suggest 6.5 could be about right, would need to avoid full-on torch conditions with lows around Christmas but as of now signals are for mild in two peaks around Friday and middle of next week, will probably push CET towards low 6 range but could then fall back after 21st. 

Guesses under 4 C would need all cold spells to max potential including possibly a very cold turn after 26 Dec. Otherwise no chance for colder calls but 5.4 could be quite good. 

[The PIT]

Sunny Sheffield up to 3.4C  -2.7C below normal. Rainfall 93.6mm 107% of the monthly average

[Roger J Smith]

It's a rare RJS update of CET ... 

4.7c to the 12th

0.1c above the 61 to 90 average (end of Dec)
0.2c below the 81 to 10 average (running 1-12 Dec)

0.6c below the 91 to 20 average (running 1-12 Dec)

 

Edited December 14, 2023 by Roger J Smith

[Roger J Smith]

I got interested in year to year variations and wondered, what are the largest year to year changes in annual temperature? 

This seems to be decreasing in the recent past, as one might expect if climate is being modified by an external factor (increasing greenouse gases).

In various epochs, these are the largest cooling changes year to year, over two years, three years, or any number of years. I took outlying warmest years as starting points, and looked for the most significant cooling changes in the period between those outliers and the next set. 

In columns C and D ( 2 yr and 3 yr drops ), no entry means that no drop was greater than the one documented for a shorter interval. 

Note a warmer year can exist than the starting peak, as with 1794 (9.9), if the next peak (like 1834 10.5) is higher and on way up to that, intervening nearly as warm years as next peak (such as 1828 at 10.3) exist. The long cycle (1794 to 1834) could be broken at sub-peaks 1806 or 1811 but all of the changes indicated would be in one or the other anyway.

 

A _________________________ B _______________ C ___________ D ________________ E

warm year __ CET _______ 1 yr drop _____ 2 yr drop ___ 3 yr drop ____ maximum drop from peak (col A)

1666 ________ 9.9 _________ 1.4 (66-67) ___ -- -- _________ -- -- __________ 2.0 (1666-1675) __ 9 yrs _____ 20 yrs to next peak

1686 ________10.2 ________ 1.2 (86-87) ___ 2.3 (86-88) __ -- -- __________ 2.9 (1686-1695) __ 9 yrs _____ 20 yrs to next peak

1706 _________ 9.8 ________ 1.0 (15-16) ___-- -- __________ -- -- __________ 1.4 (1706-1716) __10 yrs ____ 27 yrs to next peak

1733 ________10.5 _________2.3 (39-40) ___ 2.9 (38-40) __ 3.0 (37-40) __ 3.6 (1733-1740) ___ 7 yrs ____ 26,28 yrs to next peak(s)

1759,61 ____ 10.0 _________ 1.1 (75-76) ___1.1 (61-62) __ 1.3 (61-63) __ 1.5 (1761-1770) ___ 9 yrs _____ 20, 18 yrs to next peak

1779 _______ 10.4 __________2.2 (81-82) ___-- -- _______ 2.4 (79-82, 81-84) __2.6 (1779-84) __ 5 yrs _____ 15 yrs to next peak

1794 ________ 9.9 __________ 2.1 (28-29) ___-- -- _________ -- -- __________ 2.1 (1794-1814) ___20 yrs _____ 40 yrs to next peak

1834 _______ 10.5 __________1.7 (59-60) ___ -- --  _______2.2 (57-60) ____ 2.6 (1834-1860) ___26 yrs _____ 34 yrs to next peak

1868 _______ 10.4 __________1.9 (78-79) ___ -- -- ________2.1 (76-79) ____ 3.0 (1868-1879) ___11 yrs _____ 30 yrs to next peak

1898 _______ 10.1 __________1.0 (18-19) ___ -- -- __________ -- -- _________ 1.6 (1898-1917,19) _19,21 yrs __23 yrs to next peak 

1921 _______ 10.5 __________1.8 (21-22) ___ -- -- __________ -- -- _________ 1.8 (1921-1922) ____ 1 yr ______ 28 yrs to next peak

1949 _______ 10.6 __________ 1.4 (61-62) ___ -- -- ________1.9 (59-62) ____ 2.1 (1949-1963) ___14 yrs _____ 41 yrs to next peak

1990 _______ 10.6 _______ 1.3 (95-96, 09-10) _ -- -- ______ 1.6 (07-10) ___ 2.0 (2006-2010) ____ 4 yrs _____ 32+ yrs to next peak

2022 ? _____ 11.1 __________ cycle not certain to begin 2022, if warmer year occurs soon, would call it a start if not exceeded by 2039

_________________________________________

It is possible that the trend will now be generally slowly rising and these longer cycles will be difficult to define. 

The QBO effect is clear, while only 2 of 13 cycles had a larger drop over two years than any one year drop (one had an equal drop), 7 of 13 bettered their one year drop over a three year interval. The range of largest drops was 1 to 26 years but had a cluster at around 9 to 11 years. The range of peak to peak cycle lengths was 15 to 41 years, the average was 28 years (assuming the cycle arbitrarily defined as 1990-2021 does not extend past 2022). 

Within these 13 long cycles (years 1659 to 1665 are the tail end of another cycle of unknown starting point), the largest inter-cycle drop from any internal sub-peak to coldest year was between 1.4 and 3.6 C deg. Average was about 2.2 C deg. A mean of 1.9 C exists since 1898. Amplitude of cycles is slowly decreasing over time and this is largely due to rising minima, only 1/3 offset by rising maxima.

As an illustration, 2010 was 2.0 C warmer than coldest year 1740, 2022 was only 1.0 warmer than 1686, an early peak, and 1.4 warmer than any peak year selected (1706). Until natural variability provides a colder baseline, it seems logical to predict that future minima will be in the range 9 to 9.5, but even that could be optimistic. Even so, the sudden appearance of a very cold 1740 after a long interval of unusual warmth (1730s) would give some reason for optimism that a surprisingly cold year could happen. It is not known for sure if volcanic dust events led to the sudden cooling 1739-40, it is known that 1784, 1816 and 1880s, possibly also 1992, had coolings of that origin. 

 

 

 

 

[Summer Sun]

4.8c to the 13th

0.3c above the 61 to 90 average
0.1c below the 81 to 10 average

Edited December 14, 2023 by Summer Sun

[Metwatch]

EWP is up to 83.1mm as of 12th.

Very wet opening half, but thankfully will now stay around that for the rest of this week. Up to around Christmas it shouldn't rise too much, maybe up to 100-110mm, but from around Christmas to New year's I think there may be a more significant rise. Somewhere in the 130-140mm range seems like a good bet for this month's EWP total.

So another 100mm December is set in stone, which would make it the 7th December in a row to exceed 100mm.

Edited December 14, 2023 by Metwatch

[The PIT]

Sunny Sheffield up to 3.8C  -2.2C below average. Rainfall up to 94mm 107.4% of the monthly average.

Looking at the present rainfall we  are now 3rd wettest on record for us at 1107.3mm of rain. 2nd highest is 2019 with 1132.6mm so within reach although the dry spell next week makes it more 50/50 chance.

Should be another month with 100mm plus of rainfall making it five in total only 2012 and 2019 have had more with six months passing the 100mm mark.

 

Edited December 14, 2023 by The PIT

[Roger J Smith]

Looks like a top ten EWP year quite possibly, 120 mm Dec takes year to 8th and either 2nd or 3rd warmest. 

If so, would be highest combination of ranks for CET and EWP annual. 

Prior top ten (and 2023 projection for current top ten) in that regard are as follows:

(table ranks for CET are as shown, assuming 2023 in 3rd place replacing 2014, and for table rank ignoring one decimal ties for CET, EWP ties are acknowledged in top 50 but are quite rare, only one tie in current top 50 for EWP): 

 

YEAR ____ CET _ rank ___ EWP _ rank ___ combined ranks ____ both exceed

 

2023 ____ 11.1 __ 2 ____ 1153.4 _ 8 ______ 10 ______________ 8 (projected, could be t2, 7 = 9, both exceed 7)

2014 ____ 11.0 __ 3 ____ 1105.6 _ 17 _____ 20 _____________ 17 (could be t2 for one dec CET)

2020 ____ 10.8 __ 5 ____ 1097.2 _ 19 _____ 24 _____________ 19

2002 ____ 10.6 __12 ___ 1117.9 _ 12 _____ 24 _____________ 12 (t8 for one dec CET)

2000 ____ 10.2 __35 ___ 1232.4 __ 4 _____ 39 _____________ 35 (t34 for one dec CET, 35 EWP)

2019 ____ 10.4 __26 ___ 1095.0 _ 20 _____ 46 _____________ 26 (t23rd for one dec CET)

1999 ____ 10.6 __10 ___ 1036.1 _ 42 _____ 52 _____________ 42 (t8 for one dec CET, 42 EWP)

1998 ____ 10.3 __33 ___ 1062.5 _ 32 _____ 65 _____________ 33 (t28 for one dec CET, 32 EWP)

2007 ____ 10.5 __13 ___ 1022.6 _ 53 _____ 66 _____________ 53 (t13 for one dec CET, 53 EWP)

1994 ____ 10.2 __36 ___ 1050.0 _ 38 _____ 70 _____________ 38 (t34 for one dec CET, 38 EWP)

1828 ____ 10.3 __30 ___ 1073.2 _ 30 _____ 60 _____________ 30 (t28 for one dec CET, 30 EWP)

2008 ____ 10.0 __57 ___ 1089.5 _ 24 _____ 81 ______________ 57 (t52 for one dec CET)

 

(CET ranks of current top 20 EWP if not in top ranked in above list) 

Rank_EWP_YEAR __ CET _ rank (tied rank for one dec)

18_1098.6 1912 ____ 9.4 _154 (t143 one dec CET)

16_1108.2 1927 ____ 9.2 _189 (t189 one dec CET)

t14_1109.3 1782 ___ 8.0 _ 351 (t351 one dec CET)

t14_1109.3 1789 ___ 8.9 _ 261 (t257 one dec CET)

13_1116.8 1792 ____ 9.2 _203 (t189 one dec CET)

11_1130.1 1848 ____ 9.4 _148 (t143 one dec CET)

10_1144.1 1877 ____ 9.2 _200 (t189 one dec CET)

09_1146.2 1882 ____ 9.5 _137 (t124 one dec CET)

07_1160.3 1903 ____ 9.3 _163 (t160 one dec CET)

06_1195.0 1960 ____ 9.7 _ 88 (t88 one dec CET)

05_1213.0 1852 ____ 9.8 _ 78 (t71 one dec CET)

03_1244.4 2012 ____ 9.8 _ 86 (t71 one dec CET)

02_1247.3 1768 ____ 8.9 _258 (t257 one dec CET)

01_1284.9 1872 ____ 9.8 _ 87 (t71 one dec CET)

 

EWP ranks of post-2023 CET annual top 20 if not in above list

Rank_CET_YEAR __ EWP _ rank ___ CET tied rank for one dec + EWP

(22) 10.5 _ 2004 __ 973.5 __ 84 ___ (t13 for one dec)+ 84

(21) 10.5 _ 2005 __ 825.1 _ 207 ___ (t13 for one dec)+207

20_ 10.5 _ 1995 __ 840.8 _ 190 ___ (t13 for one dec)+190

19_ 10.5 _ 2003 __ 761.6 _ 234 ___ (t13 for one dec)+234 

18_ 10.5 _ 1997 __ 853.9 _ 179 ___ (t13 for one dec)+179

17_ 10.5 _ 1733 __ -- -- ___ not ranked EWP (t13 for one dec CET)

16_ 10.5 _ 1834 __ 835.2 _ 196 ___ (t13 for one dec)+196

15_ 10.5 _ 1921 __ 629.0 _ 257 ___ (t13 for one dec)+257

14_ 10.5 _ 1959 __ 827.8 _ 205 ___ (t13 for one dec)+205

11_ 10.6 _ 1990 __ 841.6 _ 189 ___ (t8 for one dec)+189

09_ 10.6 _ 2017 __ 952.5 _ 100 ___ (t8 for one dec)+100

08_ 10.6 _ 1949 __ 789.6 _ 225 ___ (t8 for one dec)+225

07_ 10.7 _ 2018 __ 912.2 _ 128 ___ (t6 for one dec)+128

06_ 10.7 _ 2011 __ 786.9 _ 226 ___ (t6 for one dec)+226

04_ 10.9 _ 2006 __ 904.7 _ 134 ___ (not tied if 2023 is 11.0)

01_ 11.1 _ 2022 __ 857.4 _ 175 ___ (not tied if 2023 is 11.0)

 

 

(ranks 21-50 for EWP are almost all in low to mid 9 CET)

(ranks 23-50 for CET, close to combined list indicated if EWP rank 51-81, year is in first list if EWP >50) 

10.4 _ (t23 CET) 1989, 1868, 1779, 2019 (EWP 21st, in list of top combined), 2016 

10.3 _ (t28 CET) 2015, 1736 (no EWP), 1828 (EWP 30th in list of top combined), 2021 (EWP 81st), 1945, 1998 (EWP 32nd, in list)

10.2 _ (t34 CET) 1938, 2000 (EWP 4t, in list of top combined), 1994 (EWP 38th, in list) 1781, 2009 (80th EWP), 1846, 1686 (not ranked EWP)

10.1 _ (t41 CET) 1831 (68th EWP), 1857, 1898, 1775 (61st EWP), 1826, 1911, 1822, 1730 (not ranked EWP), 1957, 1983, 1943

(actual CET ranks, indicated in order, count back (e.g. 1868 is ranked 24, 1943 is ranked 51)

(ranks based on top 3 2023)

 

Current top 50 EWP years,

if 2023 ends up 8th ... current projected annual total (including Dec at 120 mm)

 

50_1024.9 1930 ___ 40_1038.3 1821 ___ 30_1073.2 1828 ___ 20_1095.0 2019 ___ 10_1144.1 1877

49_1027.0 1824 ___ 39_1048.5 1866 ___ 29_1076.2 1839 ___ 19_1097.2 2020 ___ 09_1146.2 1882 

48_1028.0 1916 ___ 38_1050.0 1994 ___ 28_1079.0 1799 ___ 18_1098.6 1912 ___ 08_1153.4 est 2023

47_1028.2 1880 ___ 37_1051.1 1886 ___ 27_1079.4 1770 ___ 17_1105.6 2014 ___ 07_1160.3 1903

46_1028.3 1974 ___ 36_1052.2 1946 ___ 26_1082.7 1924 ___ 16_1108.2 1927 ___ 06_1195.0 1960

45_1031.8 1772 ___ 35_1057.0 1876 ___ 25_1083.2 1860 ___ 14t_1109.3 1782___ 05_1213.0 1852

44_1032.0 1965 ___ 34_1057.4 1958 ___ 24_1089.5 2008 ___ 14t_1109.3 1789___ 04_1232.4 2000

43_1033.8 1773 ___ 33_1061.0 1966 ___ 23_1090.4 1797 ___ 13_1116.8 1792 ___ 03_1244.4 2012

42_1036.1 1999 ___ 32_1062.5 1998 ___ 22_1092.6 1954 ___ 12_1117.9 2002 ___ 02_1247.3 1768

41_1037.2 1875 ___ 31_1064.4 1841 ___ 21_1094.6 1951 ___ 11_1130.1 1848 ___ 01_1284.9 1872 

 

EWP began in 1766. Top 50 years in order (by centuries)

1768 1770 1772 1773 1782 1789 1792 1797 1799 (9 of 35, 26%)

1821 1824 1828 1839 1841 1848 1852 1860 1866 1872 1875 1876 1877 1880 1882 1886 (16 of 100, 16%)

1903 1912 1916 1924 1927 1930 1946 1951 1954 1958 1960 1965 1966 1974 1994 1998 1999 2000 (18 of 100, 18%)

2002 2008 2012 2014 2019 2020 2023 (7 of 23, 30%)

 

frequent _ 1768-73, 1789-99, 1872-86, 1924-30, 1958-66, 1998-2002, 2008-14, 2019-2023

sparse ___ 1800 to 1820 (21 yrs, none); 1887 to 1902 (16 yrs, none); 1931-50 (20 yrs, one); 1967-1993 (27 yrs, one)

on average, one every five years, but seven cases of consecutive, five additional separated by 2 yrs)

 

Edited December 16, 2023 by Roger J Smith

[Summer Sun]

4.8c to the 14th

0.2c above the 61 to 90 average
0.1c below the 81 to 10 average

[The PIT]

No change for sunny Sheffield still at 3.8C -2.1C below average. Rainfall unchanged.

[The PIT]

Sunny Sheffield up to 4.1C -1.7C below average. Rainfall unchanged.

[Summer Sun]

4.9c to the 15th

0.3c above the 61 to 90 average
0.1c above the 81 to 10 average

[Roger J Smith]

That 4.9 was still 0.3 below the warmer 1991-2020 average of 5.2 for 1-15 Dec. 

GFS projections would take us to an outcome of 6.0, as next week (today to 22nd) all look very mild, colder 23rd to 25th, variable but on average rather mild to end of month. If that cold spell fails to happen, low to mid 6 range is possible. Not quite enough to achieve warmest year (needs 7.6 for that) but could push back into 2nd, a normal outcome would be good for 3rd warmest. Could be a tied 2nd in one dec (with 2014) and up to fate to determine rank in unseen second decimal. 

Current EWP value is around 85 mm (84.8 to 14 Dec, added almost nothing since). EWP projections to end of month on current 12z GFS run add an average of 35-40 mm, suggesting an outcome of 120-125 mm, still good for about 8th wettest year (I posted info on that a few days ago). 

I posted a table of top combined annual ranks, and 2023 now all but assured of topping that list, replacing 2014 (and 2002 in terms of ranks exceeded).

Not noted at time, but almost all of top warm, wet years are recent, only 1828 joins list of top years from era before 1994. 

Before 1994, it was normal for warmer years to be in dry to very dry category. 1921 and 1949 were very dry years. 

[The PIT]

Sunny Sheffield up to 4.4C -1.4C below average. Rainfall 94mm 107.4%

[Summer Sun]

5.1c to the 16th

0.6c above the 61 to 90 average
0.3c above the 81 to 10 average

[Addicks Fan 1981]

One thing is I think pretty definite and that is December this year will be considerably warmer than last year.    

[damianslaw]

Yes after a cold start I thought we had a good chance of a colder than average month, with a mild middle cancelled out by cold starts and ends.

Alas it looks like the rest of the month will keep levels above average, notably so right now.. last year also produced an exceptionally mild 18-31st period.

A finish either in the 5s or 6s most probable now.. 

[The PIT]

The rapid rise has now resumed. Sunny Sheffield up to 4.7C -1.0C below average. Rainfall 94.3mm 107.8% of the monthly total.

[Summer Sun]

5.4c to the 17th

0.8c above the 61 to 90 average
0.6c above the 81 to 10 average

[Summer Sun]

5.6c to the 18th

1.1c above the 61 to 90 average
0.9c above the 81 to 10 average

[The PIT]

Sunny Sheffield up to 5.1C -0.5C below average. Rainfall up to 95.9mm 109.6% of the monthly average.