April 2024 C.E.T. and EWP contests

[BlueSkies_do_I_see]

 Summer8906 If we kept the same pattern of low pressure system after low pressure system, with limited sunshine in the day and mild cloudy nights, I still think we are looking at a slightly above average CET April.  I am not sure it's possible to get a below-average CET month now given how warm the waters are around the UK.  Every time we hear of a SSW event, I think, yes, but if the source of the easterly is Eastern Europe, they themselves are experiencing above average temperatures.  To get cold weather now, you'd have to have regularly northerly and north easterly incursions.  Yes, for a week maybe, but not the whole month. The cold start always creeps upward.

Edited March 29 by BlueSkies_do_I_see

[reef]

8.8C and 74mm

Pretty average all around. Tempted to go below average but that's almost certainly a bust these days!

[Summer8906]

 BlueSkies_do_I_see I'd say it's unlikely the pattern for Week 1 persists all month.

Even if it remains changeable, I suspect we'll change to a more typical of the season NW-ly type hence colder nights and sunnier days. Week 2 does seem to be offering a change from week 1 of some form or another, and on balance looks on the cold side.

Persistent SW-lies in April has, AFAIK, not happened in even a single year since 1978 so is presumably very unlikely to happen.

Edited March 29 by Summer8906

[LetItSnow!]

 BlueSkies_do_I_see While I agree with the sentiment that it’s much harder, I disagree with this. February 2018, March 2018, November 2019, July 2020, January 2021, April 2021, May 2021 and December 2022 show it is still possible and even in a warming world our local SSTs will vary between years. It’s not too crazy a concept to me that 2024 could have a below average month. The persistent, exceptional warmth will eventually break even if only for a little while. 

[WYorksWeather]

 Summer8906 I think the problem for getting colder weather for the CET will be that if we do go drier, the south is likely to be closer to the continental influence, and there's a lot of heat over Central Europe in particular at the moment. I could easily visualise a scenario where northern and possibly even central areas of the UK stay quite cold with cold and bright northerlies, but southerly or south-easterlies for the CET region.

In terms of averages:

The 1961-1990 averages are 3.9C, 7.9C, and 11.9C.

So if as you say, the temperatures by day ranged between 10-14C in week 1, and if we say minima were in the say 4-8C range, which is pretty plausible for that sort of very wet but not overly mild pattern, we'd be averaging 7-11C, so a little below to well above average overall.

A lot of people forget just how cold average minima were for 1961-1990 - an April with quite a few cold frosty nights wouldn't have been that unusual, but we'd now consider that unseasonably cold. 

Of course, if you mean 1991-2020, that's perhaps more likely that we will end up under for the first week, as the target there is 9.0C.

 

 LetItSnow! Yep, I definitely don't think it's impossible. But in a rapidly warming month, you need a cold first third or half ideally to have much chance. And there's not really much sign of that - first week will be probably in the region of 1C above 1961-1990 I would've thought, based on most model guidance for next week.

[LetItSnow!]

 WYorksWeather I forgot to add that I don’t believe April 2024 will be the one to do it.  My CET guess for example

Edited March 29 by LetItSnow!

[Roger J Smith]

April has fewer 100 mm months than all others, just 16 out of 258 so far (and only 11 of 217 before 1983). 

The wettest April (2012) at 149.9 is also a little lower than may 1773 (151.8) and quite a bit lower than other months. 

So for the 16 cases where April did reach 100 mm,  here are the CET values associated: 

 1. 2012 _ 149.9 ___ 7.3

 2. 2000 _ 142.6 ___ 7.7

 3. 1782 _ 139.0 ___ 5.2

 4. 1818 _ 135.6 ___ 6.9

 5. 1998 _ 130.9 ___ 7.7

 6. 1829 _ 123.4 ___ 6.7

 7. 1920 _ 116.5 ___ 8.2

 8. 1882 _ 114.0 ___ 8.4

 9. 1846 _ 112.0 ___ 7.8

10. 1966_ 111.4 ___ 7.2 

11.1983 _ 110.7 ___ 6.8

12.1800 _ 103.2 ___ 9.3

13.1828 _ 102.8 ___ 8.3

14.1935 _ 101.6 ___ 8.2

15.1871 _ 100.4 ___ 8.7

16.2001 _ 100.0 ___ 7.7

(1961 and 1792 at 10.0  C were just below 100 mm but it's evident that wet Aprils are generally cool, especially in recent decades.)

[BlueSkies_do_I_see]

I just remembered Roger's request to not start conversations at the beginning of a CET competition, so apologies for my initial post. I won't add to the debate. I really hope for any kind of settled weather before the end of the month.  Happy to be well out with my 9.6C prediction in return.

Edited March 29 by BlueSkies_do_I_see

[Roger J Smith]

It's probably good to talk about issues of general interest to forecast-makers in late stages, I would just discourage numerous posts about forecasts already made etc, but clearly it's of general interest to correlate April temperature and rainfall. 

[Relativistic]

 WYorksWeather Not sure about your comment re April frosts. Think frosts in April and May have been less affected than at other times of year. April 2021 was the frostiest on record.

Apologies -- just read the above posts!

Edited March 29 by Relativistic

[syed2878]

 

For April temp 9.5c and rainfall 100MM. thank u.

[Derecho]

Based on the EC control this morning. the CET looks very warm indeed for the start of April. Gone is the push of cold air south and it is now being replaced with a very mild cyclonic south-westerly airflow. Maybe quite plumey at times if things allign right? There are still a few chilly ens in there but the Control isn't the warmest.

So whilst still looking wet it is warm with minima holding up quite well. I think a lot of people should be upping their CET guesses (though I see quite a few have gone for 10C+. Worth noting however that the GFS has low pressure continuously crossing us on its output rather then slowly backing west like the EC does. UKMO and GFS also push some chillier air down a bit more in the middle of next week. 

Edited March 30 by Derecho

[reef]

 Derecho If we get to 13th April at 10.6C, then we only need 11.8C for the remaining days of the Spring for it to be the warmest on record (assuming an 8.1C March).

It'll be quite a confusing Spring if that happens, especially if it's dull and wet overall. 

[baddie]

 Summer8906 I find SW-lies in April are often anticyclonic, so the putrid dull, damp, mild SW-lies through the whole of April would be a shocker

Perhaps an April like 2005??? Washout start, then an OK last 3 weeks

Edited March 30 by baddie

[Kirkcaldy Weather]

7.6C and 131.8MM please

[Roger J Smith]

I will amend my earlier forecast to 11.5 C, 115.7 mm.

(note to J10, my earlier forecast is edited out of post) -- going for second warmest April now.

FYI, GFS total precip to 14 April (taking off 5 expected to fall in rest of march), looks to be at least 80 mm for a grid average ... I see a similar outcome for CET to what Derecho posted earlier. A more settled second half seems possible so I won't pump up the EWP too high but you could see how it could take a run at 2012, but then it would probably cool off in last third which I don't foresee to be in the cards. 

Top 25 March - April averages (and eventual spring averages, ranks) are: 

Rank ___ YEAR ____ MAR _ APR ___ AVG _______ (MAY) __ spring ___ rank

 

 1. ______ 2011 ____ 6.8 _ 11.9 ____ 9.35________12.2 ____ 10.3 ___ 2

 2. ______ 2007 ____ 7.3 _ 11.3 ____ 9.3 ________ 11.9 ____ 10.2 ___ 4

 3. ______ 1961 ____ 8.2 _ 10.0 ____ 9.1 ________ 11.0 _____ 9.7 ___15 

 4. ______ 1957 ____ 9.2 __ 8.9 ____ 9.05________10.3 _____ 9.5 ___28

 5. ______ 1945 ____ 7.9 _ 10.1 ____ 9.0 ________ 12.2 ____ 10.1 ___ 7

 6. ______ 2014 ____ 7.7 _ 10.3 ____ 9.0 ________ 12.2 ____ 10.1 ___ 5

 7. ______ 2017 ____ 8.8 __ 9.0 ____ 8.9 ________ 13.3 ____ 10.3 ___ 1

 8. ______ 1893 ____ 7.2 _ 10.3 ____ 8.75________13.1 ____ 10.2 ___ 3

 9. ______ 1734 ____ 8.1 __ 9.3 ____ 8.7 ________ 11.1 _____ 9.5 ___27 

10.______ 1997 ____ 8.4 __ 9.0 ____ 8.7 ________ 11.5 _____ 9.6 ___20

11.______ 1779 ____ 7.9 __ 9.4 ____ 8.65________11.9 _____ 9.8 ___14

12.______ 1948 ____ 8.3 __ 9.0 ____ 8.65________11.4 _____ 9.6 ___23

13.______ 2020 ____ 6.8 _ 10.5 ____ 8.65________12.5 _____ 9.9 ___ 8

14.______ 1794 ____ 7.0 _ 10.2 ____ 8.6 ________ 11.3 _____ 9.5 ___29

15.______ 2009 ____ 7.1 _ 10.1 ____ 8.6 ________ 12.1 _____ 9.8 ___13

16.______ 2022 ____ 8.0 __ 9.2 ____ 8.6 ________ 13.1 ____ 10.1 ___ 6

17.______ 2003 ____ 7.5 __ 9.6 ____ 8.55________12.0 _____ 9.7 ___16

18.______ 2019 ____ 7.9 __ 9.2 ____ 8.55________11.2 _____ 9.4 ___32

19.______ 1943 ____ 6.5 _ 10.5 ____ 8.5 ________ 11.8 _____ 9.6 ___22

20.______ 2002 ____ 7.6 __ 9.3 ____ 8.45________11.8 _____ 9.6 ___24

21.______ 1999 ____ 7.3 __ 9.5 ____ 8.4 ________ 12.9 _____ 9.9 ___10

22.______ 1938 ____ 9.1 __ 7.6 ____ 8.35________10.7 _____ 9.2 ___56 

23.______ 1959 ____ 7.3 __ 9.4 ____ 8.35________12.8 _____ 9.8 ___12

24.______ 1830 ____ 7.7 __ 8.9 ____ 8.3 _________12.0 _____ 9.6 ___25

25.______ 1874 ____ 6.7 __ 9.8 ____ 8.25________10.0 _____ 8.8 ___91

not top 25 above, but finished top 26 spring average CETs at 9.6 +

xx _______ 1992 _____ 7.5 __ 8.7 ____ 8.1 _______ 13.6 ____ 9.9 ____ 9

xx _______ 1952 _____ 6.6 __ 9.6 ____ 8.1 _______ 13.4 ____ 9.9 ____11

xx _______ 1868 _____ 6.8 __ 8.7 ____ 7.75_______13.5 ____ 9.7 ____17

xx _______ 1990 _____8.3 __ 8.0 ____ 8.15 _______12.6 ____ 9.6 ____18

xx _______ 1822 _____7.8 __ 8.3 ____ 8.05_______12.7 ____ 9.6 ____19

xx _______ 1811 _____7.1 __ 8.9 ____ 8.0 _______ 12.8 ____ 9.6 ____21

xx _______ 1998 _____7.8 __ 7.7 ____ 7.75_______13.1 ____ 9.6 ____26

(just outside on either list)

xx _______ 1723 _____ 7.5 __ 8.9 ____ 8.2 _______11.7 ____ 9.4 ____37

xx _______ 1831 _____7.2 __ 9.2 ____ 8.2 _______12.0 ____ 9.3 ____45

rest of top 45: 1775, 1933, 1798, 2023, 2018, 1912, 1960, 1761, 1815, 1848, 1841, 1686, 2004

generally these were around 7.5-8.0 C for Mar- Apr, lowest was 1848 (7.05, 13.9 May), 2018 was 7.45.

 

_________________________________

(ranks are awarded to earlier years in cases of ties)

(note, spring ranks and averages are taken from CET tables and are not "simple arithmetic" but MAR-APR averages are simple arithmetic from posted monthly values, ignoring any "average of 31-day and 30-day" issue and unknown rounding issues etc. ... I observed in a similar exercise last autumn that new CET seasonal averages are clearly not as simple as adding three posted values and dividing by three, as used to be the case in legacy two-decimal era, it could be a 91- or 92-day average now, and/or it could be derived from averages of mean max and mean min, etc). 

[mulzy]

9.2C and 97mm

[weatherforducks]

9.5c and 90mm please

 

[damianslaw]

Another milder than average month. 9.6 degrees. The start looks milder than at first forecast, a lot of mild minima. A rather wet month as well, but expecting at least one decent dry spell at some point. Could be a shot or two of cold from the north as well.

[Mark Bayley]

9.7c please 

[Midlands Ice Age]

9.4C and 113mms please

MIA

[Weather Observer]

9.8c and 89mm please

[Godber 1]

8.4c and 77mm please.

[Mr Maunder]

9.6c and 97mm please.

MM

[damianslaw]

Interesting to note the recently very mild Aprils in top 6, 2011, 2007, 2020 and 1987 all were followed by poor wet second halves to the summer.