May 2024 C.E.T. and EWP forecast contests

[Roger J Smith]

CET May averages and other statistics

___ table includes all CET values for the period 1981 to 2023 ... bold type, warmest third, italics middle third, underlined, coolest third of years ___

___ ties indicated are in one decimal, table ranks are based on a second decimal ___

 

21.2 ... warmest daily mean (29th, 1780)

20.0 ... 15th (1833) earliest 20.0 CET day.

15.1 ... warmest May (1833)

13.9 ... 2nd warmest May (1848)

13.8 ... t-3rd warmest Mays (1758, 1788)

13.7 ... 5th warmest May (1808)

13.6 ... t-6th warmest Mays (1727, 1992)

13.5 ... t-8th warmest Mays (1784, 1868, 1919, 1947)

13.4 ... t-12th warmest Mays 2008 (tied with 1726, 1952)

13.3 ... t-15th warmest Mays 1743, 1804, 1964, 2017, 2018

13.1 ... 1998, 2022

12.9 ... 1989, 1999

12.6 ... 1990, 2016

12.5 ... 2001, 2020, 2023

12.3 ... 2006, 2014

12.2 ... 2011

12.1 ... 2004, 2009 

12.0 ... 2000, 2023 ... ... highest 30-year average (1989-2018) and 2001-2023 average

11.9 ... 1991-2020 (& 1994-2023) averages and 1988, 2007 

11.8 ... 2002, 2012

11.7 ... 1981-2010 average 

11.6 ... 1982, 1995

11.5 ... 1993, 1997

11.4 ... ... 1901-2000 average

11.3 ... 2005 .. 1971-2000 average, 1701-1800 average

11.2 ... 1981, 2019 (also 1980) ... 1961-1990 average, 1659-2023 average of all data (11.24)

11.1 ... ... 1801-1900 average

11.0 ... 1986

10.9 ... 1985

10.8 ... 2015

10.7 ... 1991, 1994, 2010 ... 1659-1700 average

10.6 ... ... ... lowest 30-year average (1687-1716, to 1690-1719) _ also 10.65 (1873-1902)*

10.5 ... 2013

10.3 ... 1983

10.2 ... 2021

10.1 ... 1987

  9.9 ... 1984 (also 1979)

  9.2 ... 1996 tied 15th coldest with four other years, the coldest in recent years)

  9.1 ... 1756 and 1877 tied 13th coldest

  9.0 ... 1692,93,94,95 and 1782 tied 8th coldest

  8.9 ... 1879, 1885, 1902 tied 5th coldest

  8.8 ... 1855 was 4th coldest

  8.7 ... 1817 was 3rd coldest

  8.6 ... 1740 was 2nd coldest

  8.5 ... 1698 was coldest May

Extreme cold

 4.2 ... mean for 1-5 May, 1979 (4.4, 3.7, 4.7, 4.4, 3.9)

 3.5 .... mean for 3-5 May, 1877 (3.2, 3.2, 4.2)

 3.1 .... coldest daily mean (8th, 1861)

_____________________________________

* The secondary minimum came after two centuries of warmer Mays with 11.61 1820-49 the peak

Post your May CET forecasts before end of day Tuesday 30th of April to avoid time penalty, or in first three days of May with increasing late penalties.

______________________________________

 

England and Wales precip (EWP) contest 

Note: this is verified against the Hadley version of EWP (1766 to present),  

The contest asks you to predict the average England and Wales precip in mm. These are the extreme values and recent averages. 

 

151.8 ___ max 1766-2023 (in 1773)

142.4 ___ second wettest in 1782 

140.7 ___ third wettest in 1967

122.7 ___ maximum 1981-2023 (in 2021) _ 118.4 in 2007 _ 115.2 in 1983

 65.1 ___ average 1994-2023 

 64.1 ___ average 1766-2023 (all data)

 63.6 ___ average 1981-2010

 62.7 ___ average 1991-2020

 10.3 ___ minimum 1981-2023 (in 2020) _  (13.7 (1991) previous)

 07.9 ___ (min 1766-2023) in 1844 

 ________________________________________________________________

Recent ... 2023_43.8 mm ... 2022 _ 59.4 mm ... 2021 _122.7 mm ... 2020 _ 10.3 mm ...  2019 _ 46.0 mm ...  2018 _ 51.9 mm ...  2017 _ 65.0 mm ... 

2016 _ 61.7 mm ... 2015 _ 86.6 mm ...  2014 _ 102.8 mm ...  2013 _ 73.9 mm ...  2012 _ 57.4 mm ...  2011 _ 46.5 mm ...  2010 _ 38.3 mm ... ... 

Enter the EWP contest in the same post as your CET temperature forecast. Scores are by rank order out of 10.0, 0.3 penalties per day late. Same deadlines apply as CET contest. 

 

... Good luck in both contests ... 

 

[SteveB]

12.8c and 56mm please 

[B87]

10.5 and 100mm please.

[Catbrainz]

11.8 and 70mm

[Polar Gael]

13.5°C and 32.1mm for me please.

[WYorksWeather]

With thanks to Roger as usual for the data breakdown, here is what is becoming my usual post of the data in graphical form.

Generally quite a flat trend for May - some evidence of a recent increase. as with most months, but unlike March and April not as far outside the range of historic variability in the averages. The real trend though as with most months is a real lack of notably cool Mays - a May under 10C was previously unusual but not extremely rare, but there now hasn't been one since 1996. Generally the records in the early 19th century seem to show a lot more variability - plenty of warm Mays but also still a fair number of cooler ones.

Of course, May is also one of the few remaining months where the old record remains unbeaten, and in fact quite an unusual situation with 15.1C being far and away the highest from 1833. No other May has even exceeded 14C! What a month that must have been. Perhaps the most extraordinary of all the monthly records, in terms of how long it has lasted without any attempt even coming close?

Too early for me to make my own prediction at this stage, but I've posted enough on this forum lately about my thoughts for May that many of you will have a good idea of what sort of range I'm going to go for. More the detail than the idea that needs to be decided.

[Methuselah]

12.7C and 100mm please, Roger.

[Addicks Fan 1981]

12.6 and 65mm.    

[chilly milly]

11.0c and 69mm please

[Shillitocettwo]

Im going to go all in or bust on this one.

  15.2.C and 48mm.

 

   Absolutely no hint of this warmth from an average even cool first third but then a historic anticyclonic heatwave will see a run of 30.C or higher days and balmy nights under a strong Sun to squeak into the record bookd

[Bobd29]

Hi 11.6C and52.8mm for me plse.

[Kirkcaldy Weather]

11.8C and 79.8mm please

[stewfox]

11.7 well overdue a average month.  88mm of rain

[summer blizzard]

12.4, 54mm. 

For the first time in some time, i see an anticyclonic pattern. Blocking over the UK and to the north and east. Shades of last May. 

 

[snowray]

12.5c, and 57mm please.

[Dancerwithwings]

12.9c & 76mm

[Leo97t]

12.0c and 50mm

[Summer18]

11.7 and 89mm

[Typhoon John]

12.4c please

[Frigid]

Quite a chilly month with a lot of blocking, potentially our first below average CET month. 

10.8C and 45mm. 

[JeffC]

12.5C and 70mm please

[Addicks Fan 1981]

Lowering my CET guess now to 11.6 thanks to the negative AO/NAO.    

[virtualsphere]

12.2C and 73mm please

[SummerShower]

A month that will take a while to warm up, but not as bad as 1996 or 2021.  More 2013 style.  Not as wet as months gone by either, but not completely dry.

10.9 and 59mm

[WYorksWeather]

Right, time to go for this one. There's nothing really to hint at this other than a few suggestions in the extended GFS. I will go for a notably warm and relatively dry May, not quite record-breaking but the warmest in modern times with 14.3C, and 40mm of rain.

In terms of the character of the month we are pretty sure of a warm first two or three days, then I'll go with cyclonic and near average, before a benign and warm period from around May Day through mid-month, broken down by thunderstorms. Then back near or slightly above average again for a few days with a bit more rain, before a notable hot spell in the final 10 days, which will include the first 30C of the year.

I could hardly go with anything else after everything I've been saying on the forum about May lacking many recent records and so on over the past couple of months!