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

[Summer Sun]

5.8c to the 19th

1.3c above the 61 to 90 average
1.1c above the 81 to 10 average

[The PIT]

Sunny Sheffield up to 5.2C -0.3C below average. Rainfall 96.5mm 110.3% of the monthly average.

[Summer Sun]

5.9c to the 20th

1.4c above the 61 to 90 average
1.3c above the 81 to 10 average

[Roger J Smith]

EWP around 102 mm now, will add about 40-45 mm over rest of December to end around 142-147 mm. That is higher than all forecasts so I can score the contest any time. Will wait until around 27 Dec however.

CET will keep rising steadily to 24 Dec, at a near-record rate, so could be close to 6.8 C by 25 Dec, average for 26-31 Dec looks near normal and if it were to be 5.0 for six days, 6.8 would only deflate a bit, to 6.5 C. Only Typhoon John at 7.0 C is above that projection, with davehsug at 6.3 next warmest. Top ten on this forecast (eleven after ties) is rounded out by Summer Sun (5.9), PIT (5.8), Reef (5.8), I Remember Atlantic 252 (5.7) and summer blizzard (5.6), noname_weather (5.6). 

Best combined effort appears to be virtualsphere (6.0, 136.0) who looks likely to finish either 2nd or 3rd CET and probably first EWP, but could also be first CET if that ends up 6.1 or 6.0. ... virtualsphere was in early with that one, ahead of syed2878 and froze were the days also at 6.0. That rounds out the likely top five CET, so top six EWP after virtualsphere would be Frigid (135.0), Don (130.0), noname_weather (129.0) and at 124.0 for 5th, 6th (ProlongedSnowLover and Godber1).  Snowray, J10, Feb1991blizzard, and cheeky monkey round out top ten. (assuming we do see at least 25-30 mm of projected 40-45, if it turned out lower this would require an edit). 

[Frigid]

Mildest December since 2015 on the cards now, possibly breaching the 7.0C mark. It's just been continuously mild since the 5th. Dire, dire month it has to be said. 

[LetItSnow!]

Certainly one of the poorer Decembers of my lifetime. Probably a tad better than December 2018 but that isn't saying much.

[WYorksWeather]

2 hours ago, Frigid said:

Mildest December since 2015 on the cards now, possibly breaching the 7.0C mark. It's just been continuously mild since the 5th. Dire, dire month it has to be said. 

I suppose it's possible, but recent output is showing a return to something closer to average next week, which I think will be enough to avoid the required 8C average required for a 7.0C finish. If I had to guess the final outcome to the nearest 0.5C I'd go with 6.5C.

[TillyS]

8 hours ago, LetItSnow! said:

Certainly one of the poorer Decembers of my lifetime. Probably a tad better than December 2018 but that isn't saying much.

Several mild to very mild days ahead, and some mild nights too with a potentially record-breaking warm Christmas Eve (15.6C is the record). Cooler after Christmas.

One great thing about this, which I personally feel keenly, is that it’s keeping down the heating bills. This forum isn’t a place for guilt-tripping others about weather, but all I’ll say is that it sure does help at a very difficult time financially for many of us.

Pretty certain to finish in the 6’s now and the 7’s by no means out of the question. What a dramatic turnaround from those first few days.

 

 

 

[Summer Sun]

6.1c to the 21st

1.6c above the 61 to 90 average
1.5c above the 81 to 10 average

[The PIT]

Sunny Sheffield up to 5.6C 0.2C above average. Rainfall up to 102.8mm 117.5% of the monthly average.

The 5th month of the year to pass 100mm mark.  Going to be close whether the year moves into the 2nd place in regards to wettest recorded years we've recorded since 1955. 2012 is safe though.

[Roger J Smith]

Japan recently went from very mild record breaking temps (in mid 20s even outside subtropical southern areas), to very cold with snow. So pattern change can still occur in the northern hemisphere. Looks quite cold to end Dec so CET probably will fall back from a peak near 7 C by 25th, into the mid 6 range. 

It is also quite mild at my location, 4 C and rain, normally snowing a fair bit and -2 to -5 C temps but not like that so far, will end up with about same anomaly in +2C range. 

Edited December 22, 2023 by Roger J Smith

[The PIT]

Sunny Sheffield up to 5.8C +0.5C above average. Rainfall 104.2mm 119.1% of the monthly average.

Going through local forecast gives us a final figure of 5.9C. +1.1C above average. Long way to go yet and things can change

[Roger J Smith]

I feel pretty confident that EWP will exceed 136mm (our highest forecast) which means that points are more or less set, and errors will all change in lock-step if we blow past my current estimate of 145mm. So here is your first look at EWP contest scoring. Same procedures as previous contest years. It works out in similar ways to CET scoring. There are scoring levels from 0.0 to 10.0 (instead of 0 to 100 as in CET). Instead of adding bonus points, I subtract penalty points for the same aspects, for example, you lose 0.06 for being wrong side of 1991-2020 normal (with a graduated scale for first six closest to normal penalized). You lose .01 for every 10% you exceed best forecast in percentage error (it's like the accuracy points in CET). You lose 0.3 for each late day. One thing I do a bit differently is to deduct only a half a scoring level for later duplicates; this is partly because there are fewer duplicates, and also, if two forecasts tie for errors on different sides of the target, they are scored equally (unless one gets wrong-sign penalty or is late). Order of entry still plays a role in EWP. I think it is just about the same scoring system as CET overall. 

The table contains CET predictions so I can easily convert this into a "best combined" and CET ranking early indication as usual, but official CET scoring is announced by J10 later. I am not as confident of CET being closer to 7.0 than 6.3 but I believe it will be between our two highest forecasts so I did the best combined rank setting based on 6.9 -- Typhoon John does not enter EWP anyway so it won't affect best combined results at all if the 1-2 finish indicated for CET is reversed. It would affect it a little if outcome is below 6.2 C. (edit 24 Dec, below 6.5 looks less likely now)

 

Results for DEC 2023 _ Subject to any later adjustments _ based on 7.0 C and 162 mm

 

Ranks _____ CET _ EWP __ FORECASTER (Order of entry) ___ Best combined _____________ EWP scoring (pts, err)

CET EWP

_01 _ ---- ___7.0 __ --- --- __ Typhoon John ( 11 ) ______________ ---

_02 _ 17 ___ 6.3 _ 108.0 __ davehsug ( 41 ) __________________19 ___ 4th best combined ___ 6.96 ___ 54.0 mm (17) 

_03 _ 01 ___ 6.0 _ 136.0 __ virtualsphere ( 6 ) ________________ 4 ___ best combined _______10.00 ___ 26.0 mm (1)

_04 _ 52 ___ 6.0 __ 50.0 __ syed2878 ( 16 ) ___________________56 ___ t21st best combined __ 0.19 ___112.0 mm (52)  

_05 _ ---- ___6.0 __ --- --- __ Froze were the Days ( 38 ) _______ --- 

_06 _ ---- ___5.9 __ --- --- __ Summer Sun ( 37 ) _______________ ---

_07 _ 36 ___ 5.8 __ 80.0 __ The PIT ( 18 ) _____________________ 43 ___16th best combined ___ 3.41 ____82.0 mm (t34)

_08 _ 29 ___ 5.8 __ 87.0 __ Reef ( 32 ) ________________________ 37 ___14th best combined ___ 4.56 ____75.0 mm (29)

_09 _ 13 ___ 5.7 _ 112.0 __ I remember Atlantic252 ( 27 ) ____ 22 ___t6th best combined ___ 7.72 ____50.0 mm (13)

_10 _ 40 ___ 5.6 __ 74.0 __ summer blizzard ( 20 ) ____________50 ___19th best combined ___2.47 ____88.0 mm (40) 

_11 _ 04 ___ 5.6 _ 129.0 __ noname_weather ( 39 ) ___________15 ___2nd best combined ___ 9.43 ____33.0 mm (4)

_12 _ 10 ___ 5.5 _ 118.0 __ chilly milly ( 13 ) __________________ 22 ___t6th best combined ___ 8.29 ____44.0 mm (10)

_13 _ 03 ___ 5.4 _ 130.0 __ Don ( 34 ) _________________________16 ___ 3rd best combined ___ 9.62 ____32.0 mm (3)

_14 _ 08 ___ 5.4 _ 120.0 __ J 10 ( 53 ) _________________________ 22 ___t6th best combined ___ 8.67 ____42.0 mm (8.)

_15 _ 09 ___ 5.3 _ 119.0 __ Feb1991blizzard ( 30 ) ____________24 ___10th best combined ___8.48 ____43.0 mm (9)

_16 _ 07 ___ 5.3 _ 121.5 __ snowray ( 40 ) ____________________ 23 ___ 9th best combined ___ 8.86 ____40.5 mm (7)

_17 _ 16 ___ 5.3 _ 110.0 __ seaside60 ( L1-2 ) _________________33 ___12th best combined ___7.03^___ 52.0 mm (t14)  

_18 _ 02 ___ 5.2 _ 135.0 __ Frigid ( 35 ) _______________________ 20 ___ 5th best combined ___ 9.81 ____27.0 mm (2) 

_19 _ 15 ___ 5.2 _ 110.0 __ Addicks Fan 1981 ( 48 ) ___________34 ___13th best combined ___7.43 ____52.0 mm (t14) 

_20 _ 12 ___ 5.2 _ 114.0 __ February1978 ( 55 ) ______________ 32 ___11th best combined ___7.91 ____48.0 mm (12)

_21 _ 24 ___ 5.1 __ 96.0 __ moorlander ( 7 ) __________________ 45 ___t17th best combined __ 5.58 ____66.0 mm (24) 

_22 _ 47 ___ 5.1 __ 63.0 __ SteveB ( 10 ) ______________________ 69 _____ ___ ___ ___ ___ ___ ___ __1.14 ___ 99.0 mm (47)

_23 _ 22 ___ 5.1 __ 98.0 __ rwtwm ( 36 ) _______________________45 ___t17th best combined __5.98 ____64.0 mm (22) 

_24 _ 44 ___ 5.1 __ 67.0 __Mr Maunder ( 42 ) _________________ 68 _____ ___ ___ ___ ___ ___ ___ __1.71 ___ 95.0 mm (44)

_25 _ 31 ___ 5.0 __ 83.0 __ Bobd29 ( 3 ) _______________________ 56 ___t21st best combined ___4.18 ___79.0 mm (31)

_26 _ 35 ___ 5.0 __ 80.0 __ Earthshine ( 14 ) __________________ 61 ___ 25th best combined ___ 3.51 ___82.0 mm (t34) 

(27) _(17.6) _ 4.9 _ 106.3 _____ 1993-2022 average ___________ 44.6 __17th best combined ___6.86 ___55.7 mm (17.6)

_27 _ 27 ___ 4.9 __ 88.0 __ methuselah ( 5 ) __________________ 54 ___ 20th best combined ____4.98 ___74.0 mm (t27)

_28 _ 49 ___ 4.9 __ 59.0 __ dancerwithwings ( 19 ) ____________ 77 _____ ___ ___ ___ ___ ___ ___ ___ 0.76 __103.0 mm (49)

(29) (27) ___ 4.8 __ 88.0 _____ Consensus _____________________56 ___t21st best combined ____ 4.98 ___ 74.0 mm (t27) 

(29) (19.1) _ 4.8 _ 103.6 _____ 1991-2020 average ____________ 48.1__ 18th best combined ___ 6.55 ____58.4 mm (19.1)

_29 _ 50 ___ 4.8 __ 56.0 __ summer shower ( 28 ) _____________ 79 _____ ___ ___ ___ ___ ___ ___ ___ 0.57 ___106.0 mm (50)

_30 _ ---- ___4.8 _ --- --- __ Mark Bayley ( 45 ) __________________ ---- 

_31 _ 11 ___ 4.7 _ 115.0 __ WYorksWeather ( 33 ) ______________ 42 ___15th best combined ___ 8.10 ____47.0 mm (11)

(32) (22.4)_ 4.5 __ 97.4 _____ 1981-2010 average ______________ 54.4 __ 20th best combined __ 5.90 ____64.6 mm (22.4)

_32 _ 48 ___ 4.5 __ 60.0 __ Leo97t ( 26 ) ________________________ 80_____ ___ ___ ___ ___ ___ ___ ___0.95 ___102.0 mm (48.)

_33 _ 30 ___ 4.4 __ 85.0 __ Weather26 ( 2 ) _____________________ 63_____ ___ ___ ___ ___ ___ ___ ___4.37 ___ 77.0 mm (30)

_34 _ 37 ___ 4.4 __ 77.0 __ Somerset girl ( 49 ) _________________ 71 _____ ___ ___ ___ ___ ___ ___ __ 3.04 ___ 85.0 mm (37) 

_35 _ 21 ___ 4.3 __ 99.0 __ Wold Topper ( 57 ) _________________ 56 ___t21st best combined ___ 6.18 ____63.0 mm (21)  

_36 _ 34 ___ 4.2 __ 80.0 __ John88b ( 8 ) ________________________70 _____ ___ ___ ___ ___ ___ ___ __ 3.61 ___ 82.0 mm (t34) 

_37 _ 41 ___ 4.2 __ 72.0 __ gazse9 ( 9 ) _________________________ 78 _____ ___ ___ ___ ___ ___ ___ __ 2.28 ___ 90.0 mm (t41)

_38 _ 28 ___ 4.2 __ 88.0 __ summer18 ( 17 ) ____________________66 _____ ___ ___ ___ ___ ___ ___ __ 4.88 ___ 74.0 mm (t27)

_39 _ 26 ___ 4.2 __ 90.0 __ Mulzy ( 46 ) _________________________ 65 _____ ___ ___ ___ ___ ___ ___ __ 5.18 ___ 72.0 mm (26)

(40) (26.5) _ 4.1 __ 89.1 ___ average of all data (CET 1659-2022, EWP 1766-2022)  66.5 ___ ___ ___ ___ ___ __ 5.09 ___ 72.9 mm (26.5)

_40 _ 32 ___ 4.1 __ 81.0 __ Alexis J9 ( 4 ) ________________________72 _____ ___ ___ ___ ___ ___ ___ ___ 3.99 ___ 81.0 mm (t32) 

_41 _ 25 ___ 4.1 __ 95.0 __ Metwatch ( 44 ) _____________________66 _____ ___ ___ ___ ___ ___ ___ ___ 5.38 ___ 67.0 mm (25)

_42 _ 19 ___ 4.0 _ 100.0 __ DR(S)NO ( 29 ) ______________________61 ___t25th best combined __  6.38 ___ 62.0 mm (20) 

_43 _ ---- ___4.0 __ --- --- __ damianslaw ( 43 ) __________________ ----

_44 _ 51 ___ 3.9 __ 51.0 __ shillitocettwo ( 22 ) _________________ 95 _____ ___ ___ ___ ___ ___ ___ ___ 0.38 ___111.0 mm (51)

_45 _ 39 ___ 3.9 __ 75.0 __ daniel* ( 56 ) ________________________84 _____ ___ ___ ___ ___ ___ ___ ___ 2.75 ___ 87.0 mm (t38.) 

_46 _ 38 ___ 3.8 __ 75.0 __ stewfox ( 12 ) _______________________ 84 _____ ___ ___ ___ ___ ___ ___ ___ 2.85 ___ 87.0 mm (t38.) 

_47 _ 18 ___ 3.8 _ 105.0 __ Midlands Ice Age ( 50 ) _____________ 65 _____ ___ ___ ___ ___ ___ ___ ___ 6.77 ___ 57.0 mm (18.) 

_48 _ 33 ___ 3.7 __ 81.0 __ Emmett Garland ( 31 ) ______________ 81 _____ ___ ___ ___ ___ ___ ___ ___ 3.89 ___ 81.0 mm (t32)  

_49 _ 53 ___ 3.6 __ 21.0 __ Neil N ( 21 )  _______________________ 102 _____ ___ ___ ___ ___ ___ ___ ___ 0.00 ___141.0 mm (53) 

_50 _ 42 ___ 3.6 __ 72.0 __ Weather Observer ( 51 ) ____________ 92 _____ ___ ___ ___ ___ ___ ___ ___ 2.18 ___ 90.0 mm (t41)

_51 _ ---- ___3.3 __ --- --- __ Kentish Man ( 54 ) _________________ ----

_52 _ 43 ___ 3.2 __ 71.0 __ jonboy ( 24 ) ________________________ 95 _____ ___ ___ ___ ___ ___ ___ ___ 1.90 ___ 91.0 mm (43)

_53 _ 06 ___ 3.1 _ 124.0 __ godber 1 ( 52 ) _____________________ 59 ___24th best combined __ __ 9.14 ___ 38.0 mm (t5)

_54 _ 14 ___ 3.0 _ 110.0 __ Jeff C ( 1 ) ___________________________68 _____ ___ ___ ___ ___ ___ ___ ___ 7.53 ___ 52.0 mm (t14)

_55 _ 45 ___ 2.9 __ 64.7 __ Roger J Smith ( 23 ) ________________ 100 _____ ___ ___ ___ ___ ___ ___ ___1.52 ___ 97.3 mm (45)

_56 _ 46 ___ 2.8 __ 64.0 __ Stationary Front ( 25 ) _____________ 102 _____ ___ ___ ___ ___ ___ ___ ___ 1.33 ___ 98.0 mm (46)

_57 _ 20 ___ 2.8 __104.0 __ Let It Snow! ( L1-1 ) ________________ 77 _____ ___ ___ ___ _ (lev 19) ___ _ 6.28^___58.0 mm (19) 

_58 _ 05 ___ 2.4 _ 124.0 __ prolongedSnowLover ( 47 ) ________ 63 _____ ___ ___ ___ ___ ___ ___ ___ 9.24 ___ 38.0 mm (t5)

_59 _ 23 ___ 2.0 __ 96.5 __ Polar Gael ( 15 ) ____________________ 82 _____ ___ ___ ___ ___ ___ ___ ___ 5.78 ___ 65.5 mm (23)

 

note: ranks for error are in brackets after EWP error. No CET scoring info is contained, just ranks from table of entries. Late penalty jogs not used here, and will work out in CET scoring tables. Assume a drop of one rank per late day relative to rank indicated here. ... EWP scores affected by late penalties are shown with ^ symbol. If rank is pushed down, this is indicated by "level" which will also be reflected in error rank (t ose are not adjusted for late days). Error ranks are also tied for entries in different order. 

also note: best combined total ranks are shown for all entrants, but are ranked only for top 25. 

also note: Ranks for normals and consensus are in decimal form, indicating where they are located relative to integer ranks of contest entrants. 

 

EWP forecasts in order

136_virt .. 135_Frig .. 130_Don .. 129_non .. 124_pSL, godb .. 121.5_snow .. 120_ J10 ..

119_feb91 .. 118_cm .. 115_WYorks .. 114_Feb78 .. 112_IRem .. 110_ Jeff, Add,sea^ .. 108_ dave ..

106.3 _93-22 .. 105_mia .. 104_LIS^ ..103.6 _91-20 .. 100_DR(S) .. 99_WT .. 98_rwtwm .. 97.4 _81-10 ..

 96.5_PG .. 96_moor .. 95_Met .. 90_Mul ..  89.1 _alldata ...88_meth, sum18 .. 88.0_con .. 87_Reef ..

 85_wx26 .. 83 _bobd .. 81_Al J9, EG .. 80_john, earth, PIT .. 77_sg .. 75_stew, dan ..

 74_sb ... 72_gaz, WxOb .. 71_jon .. 67_MrM .. 64.7 _RJS .. 64_SF .. 63 _Ste .. 60_leo ..

 59_dww ..  56_sumsh .. 51_shil .. 50_syed .. 21_NN

_________ 

51 on-time entries, and two late (^) 1d, 53 total ... median (consensus) 88.0 mm.

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

Edited January 1 by Roger J Smith

[Summer Sun]

6.3c to the 22nd

1.8c above the 61 to 90 average
1.7c above the 81 to 10 average

[I remember Atlantic 252]

I really only went 5.7C, bloody 'eck will be way out

[Scorcher]

The last week or even 10 days has been 2015-esque. Really exceptionally mild and consistently so.

Even in December 2015 I don't remember waking up to many 13C mornings.

Personally even though I don't enjoy prolonged cold, I would prefer something colder and more seasonal around Christmas.

[The PIT]

Sunny Sheffield up to 6.1C +0.9C above average. Rainfall 111.2mm 127.2% of the monthly average.

[Summer Sun]

6.5c to the 23rd

1.9c above the 61 to 90 average
1.9c above the 81 to 10 average

[Roger J Smith]

EWP update _ around 108 mm now, GFS still gets it to 145-150 mm (approx) by end of Dec. 

CET has been near record mild, not quite setting any daily records so far, but it could do so today (will report on it tomorrow). Looking at model output, if I assume we are at or about 7.0 after both today and 25 Dec, then the last six days will only reduce that to 6.8 or 6.9 (GFS). There was colder guidance in past few days. The European model also looks to flat-line near 7 C with just a slight fall on 30 Dec suggested. Would now say a range of 6.7 to 7.1 looking good (for Typhoon John in particular). Will edit scoring table accordingly. 

[LetItSnow!]

11 hours ago, Scorcher said:

The last week or even 10 days has been 2015-esque. Really exceptionally mild and consistently so.

Even in December 2015 I don't remember waking up to many 13C mornings.

Personally even though I don't enjoy prolonged cold, I would prefer something colder and more seasonal around Christmas.

You know it's bad when Scorcher wants things to return closer to average!

[WYorksWeather]

1 hour ago, Roger J Smith said:

EWP update _ around 108 mm now, GFS still gets it to 145-150 mm (approx) by end of Dec. 

CET has been near record mild, not quite setting any daily records so far, but it could do so today (will report on it tomorrow). Looking at model output, if I assume we are at or about 7.0 after both today and 25 Dec, then the last six days will only reduce that to 6.8 or 6.9 (GFS). There was colder guidance in past few days. The European model also looks to flat-line near 7 C with just a slight fall on 30 Dec suggested. Would now say a range of 6.7 to 7.1 looking good (for Typhoon John in particular). Will edit scoring table accordingly. 

A 7C finish would be truly extraordinary after the cold start. That would mean that the rest of December would have averaged 8.4C! It would also make it the mildest December since the famous (or infamous, depending on your perspective) December 2015.

[Roger J Smith]

Yes, it will get 2023 back into range of tying 2022 for annual CET in one decimal (11.1), we will have to wait and see the decision on that. A colder Dec average was going to make the question of 2nd or 3rd rank against 2014 (11.0) ... 

This will also be the warmest year on record at NYC (in 155 years), beating 2012, and fifth warmest at Toronto, in 184 years of record. It will also be NYC's lowest calendar year snowfall (1913 3.4", 2023 to date 2.3") if it does not snow at least 1.2" now to 31st. Last winter 2022-23 was also least snowy of all winters at NYC (again 2.3"), but so far this one has only recorded trace amounts. 

At 7.0 or 7.1C, ((CET)) it would be 15th warmest Dec all-time, and neither of those values exists in v2.0 data set. At 6.9 it would join four others now ranked 15th to 18th. At 6.8 it would join four currently ranked 19th to 22nd. 

[The PIT]

Sunny Sheffield up to 6.3C +1.3C above average. Rainfall up to 112.6mm 128.7% of the monthly average.

Latest look at local forecast gives 6.5C so a range of 6.3C to 6.7C for final figure in Sunny Sheffield.

Unless this winter bucks the trend a figure above 6C means the winter will be above average. One of those strange quirks.

 

Edited December 25, 2023 by The PIT

[Summer Sun]

6.7c to the 24th

2.2c above the 61 to 90 average
2.1c above the 81 to 10 average

[Roger J Smith]

New CET records for 24 Dec were set in all three categories: 

max 13.4 (replaces 12.9 1997)

mean 11.3 (replaces 10.7 1843) _ 1843 was before max, min period of record so not sure if it could have set higher max or min

 9.3 (replaces 8.9 1977) 

 

Edited December 25, 2023 by Roger J Smith