April 2024 C.E.T. and EWP contests

[snowray]

 BlueSkies_do_I_see l think that you can change upto and including the 3rd of the month, with penalties of course.

[Derecho]

Unless meteociels table tools are playing up it is looking like a remarkable start to April with a CET of 11.8C on the 7th according to the 00z EC control. Some cooler weather briefly after that but not for long (if that does indeed happen!)

Note however, the EC is keenest to push some very warm air over us next weekend. Even with the biased EC maxes, they may be a bit too warm here.

 

Edited April 2 by Derecho
Tweaked Rothamstad's estimated returns

[LetItSnow!]

 Derecho All conjecture from me at this point but I wouldn't be surprised to see high pressure nose in from the south (See my latest Model Output blabber if interested). I wonder if this April may pan out like a warmer version of April 1987; very warm but not overly dry due to an unsettled start. I honestly would not be ruling out a 11+C CET this April already, though a northerly dominated second half could put a quick death to this idea. April 1995 is a good example of a very warm April turning into a mild April due to a cold second-half. Wouldn't want to bet on that at this time though.

[Addicks Fan 1981]

 Derecho I have to say that the ECM control have been pretty good of late and although I have aimed low I am under the illusion that spring 2024 could even be the warmest on record.   

[Roger J Smith]

 BlueSkies_do_I_see

Apologies I did not really take in your request (?), are you actually wanting a revision to 11.6? (if you do there would be a late penalty to the time of your post, which looks to be two days? I see posting times in my own time zone which can be confusing for me. 

So it's your choice, you didn't quite say "for sure I want to change to 11.6" but I didn't respond to it yesterday. 

 

 

[Summer Sun]

9.6c to the 2nd

1.7c above the 61 to 90 average
1.4c above the 81 to 10 average

[BlueSkies_do_I_see]

 Roger J Smith No thanks Roger. I will remain at 9.6C. I don't believe in changing a prediction after the deadline.

[reef]

I think what has been rather notable this year so far is how warm we've managed to be despite pretty bad synoptics. It kind of makes you wonder what sort of CET values we'd be hitting if we had perfect synoptics. 

Its certainly looking like we'll be around the 11C mark mid-month, so at least a top 20 finish looks very likely at that point.

A warm spell in the second half and we'll be threatening the record which has already fallen twice in the last 17 years.

[WYorksWeather]

 reef Again, way too early to be seriously talking about this, but I actually think it's beyond that. If we're close to 11C by mid-month with nothing particularly spectacular having happened, and then we get a proper early warm spell later on with a few days widely into the low to mid 20s, we could even be looking at an April answer to December 2015, with a finish at something like 13C.

Very low probability of that, but I do think an 11C to mid-month plus a notable warm spell in the second half would achieve that. It's not likely though - I have a hunch that we'll get a few days of northerlies at some point which will bring the CET back down to something sensible, but still well above average.

[Derecho]

 WYorksWeather  It's been overlooked on here (easy to see why it would be) but EC 12z member 7 goes for the most bonkers scenario for mid month with this early heatwave...

The 20C hpa line covers much of the UK at the above point. If that scenario came off, we'd be looking at a CET of around 13.5C to the 18th and a CET of 17C from the 12th to 18th!!

I doubt it will though it's a crazy run.

Edited April 3 by Derecho

[reef]

 WYorksWeather Agreed its too early, but as April is a warming month it would be exceptionally difficult to see us coming much below 9-10C if we're already at 11C mid-month. It would take a very cold second half.

The signs are there already that it's going to be well above average, it just depends how this pattern breaks or even if it continues. If we get a whole month of this, it'll gradually warm and we'll finish in the 11s. If we get a cold spell, 9s maybe. If we get a plume, who knows how high?

[Relativistic]

What's the earliest date the 20°C line's reached our shores? Anyone know?

[LetItSnow!]

 Relativistic

Unless there’s some date in May from ages ago that was a missed opportunity type event like September 1988 and June 2019, the earliest is when in the mostly mild and bland summer of 2000 the 20C grazed the southwest coast on June 18th, 2000 

[Roger J Smith]

Two of the warmest seven-day intervals in April, against warmest seven days of April 2011 and 2018, include:

1893 ___ 1945 ___ 2011 ___ 2018

19-25 __ 14-20 __ 19-25 __ 16-22

14.3 ____ 11.8 ____ 13.3 ____ 11.1

16.7 ____ 16.3 ____ 13.4 ____ 13.2

15.8 ____ 17.1 ____ 15.5 ____ 17.0

13.9 ____ 14.4 ____ 15.4 ____ 17.7

13.0 ____ 14.6 ____ 15.9 ____ 14.5

13.9 ____ 14.6 ____ 13.5 ____ 14.3

15.0 ____ 14.8 ____ 12.8 ____ 14.5

avg _____ avg _____ avg _____ avg

14.66 ___ 14.80 ___ 14.26 ___ 14.61

In mid-April 1949, two days near 16 and a weekly average 12-18 of 13.8 C.

In April 2007, two intervals of about 3-4 days with comparable temps, not quite a sustained week to compare. 

Then of course the end of April 1775, 26-30 April average was 16.7 (24-25 only 11.0, so a seven day average of 15.1 C).

These are the most impressive warm spells in April in the records. As the 1775 spell stayed warm into early may, it managed an average near 16 C for seven days if we include 1-2 may. 

 

 

Edited April 4 by Roger J Smith

[WYorksWeather]

 LetItSnow! Someone in the model thread found one from February 29th 1960! It did nothing at the surface though, so not sure what happened with that...

EDIT: Not a 20C actually just remembered, but around 17-18C. Still ridiculous though.

Edited April 4 by WYorksWeather
Correction.

[kold weather]

Already a pretty high CET in a period where the months averages are only going one way. 

Looks like above 61-90 already is basically guaranteed. Above longer term average also is highly likely.

What do we need for the warmest first 4 months ever? I'm guessing 2007 is still the king on that metric? Jan 24 was much cooler than 07 but both Feb and Mar were decently warmer in 24.

[BlueSkies_do_I_see]

 kold weather I think I calculated 9.5C to secure that title.  I may be mistaken though.

Edited April 4 by BlueSkies_do_I_see

[Summer Sun]

9.9c to the 3rd

2.0c above the 61 to 90 average
2.0c above the 81 to 10 average

[reef]

 kold weather Its 11.1C required to beat 2007.

The warmest first 5 months on record is actually an easier hit. That requires April and May to have 23.0 cumulative degrees between them, so a 10.5C April and 12.5C May would do it. I say easier, but it would make Spring 10.4C and also the warmest on record!

Edited April 4 by reef

[BlueSkies_do_I_see]

Thanks Reef.  We won't be far away from that 11.1C after the first part of the month I think. Some really mild days coming up. Personally, I think the month will finish north of that judging by the GFS 6Z and the general model trends.  Practically all the weather is coming from the south / south west as far as the forecast goes out to.  Couple it with cloud, wind and rain, I can't see where any notable cold will be coming from.

Edited April 4 by BlueSkies_do_I_see

[Roger J Smith]

Top ten CET averages after JAN, FEB, MAR and APR ... I calculated them by simple arithmetic of adding four monthly values and dividing by four, no doubt the metoffice would come up with slightly different values using some other formula but the order is probably going to be same ...

 

Rank __ YEAR ___ JAN_FEB_MAR_APR ___ average** ____ 2024 needs to tie (20.6 so far)

_ 01 ___ 2007 ___ 7.0 _ 6.0 _ 7.3 _ 11.3 ____ 7.88 (7.90) _____ 11.0

_ 02 ___ 2020 ___ 6.4 _ 6.5 _ 6.8 _ 10.5 ____ 7.55 (7.55) ______ 9.6

_t03 ___ 1990 ___ 6.5 _ 7.3 _ 8.3 __ 8.0 ____ 7.53 (7.51) ______ 9.5

_t03 ___ 2014 ___ 5.8 _ 6.3 _ 7.7 _ 10.3 ____ 7.53 (7.53) ______ 9.5

_ 05 ___ 2002 ___ 5.5 _ 7.0 _ 7.6 __ 9.3 _____ 7.35 (7.32) ______ 8.8

_t06 ___ 1961 ___ 3.9 _ 6.9 _ 8.2 _ 10.0 _____ 7.25 (7.24) ______ 8.4

_t06 ___ 2011 ___ 3.8 _ 6.5 _ 6.8 _ 11.9 _____ 7.25 (7.21) ______ 8.4

_ 08 ___ 1957 ___ 5.5 _ 5.3 _ 9.2 __ 8.9 _____ 7.23 (7.25) ______ 8.3

_t09 ___ 1733 ___ 6.9 _ 6.0 _ 5.9 _ 10.0 _____ 7.20 (7.21) ______ 8.2

_t09 ___ 2022 ___ 4.7 _ 6.9 _ 8.0 __ 9.2 _____ 7.20 (7.18) ______ 8.2

 

11-21 are t11 1734&1779 (7.03), t13 1686&1943&2017&2019 (7.00) 17 1998 (6.95). 18 1999 (6.90)

and t19 1834&1921&1938 (6.88) ... several incl 2023 are t22 at 6.85

** average (second value in brackets is daily mean). A somewhat different order is created by using that method.

Edited April 4 by Roger J Smith

[WYorksWeather]

I think it's still too early to have any real confidence in a record-challenging April. But you have to say that you could hardly have a better run at it, with a likely 11C by mid-month. If we dropped in something along the lines of 17th-22nd April 2018 in the latter half, you could be looking at something absolutely ridiculous. But of course April can bring a taste of late winter, so if we do get a northerly it'd bring it down to something more reasonable.

 

[WYorksWeather]

 Roger J Smith I think the Met Office will probably work right back to the raw figures - take the daily min and max and average them for each day, then just divide by the number of days, so 121 in this case. But you're right, it's not going to change the order between 1 and 2. It might change the order of the current 2-4 though as they're very close, and same for 6-10.

Already, it looks like it will take a notably cool second half of April to stop the CET achieving second place, at a minimum.

[Roger J Smith]

So I worked out daily averages for top ten, all are quite close and if Feb was a warmer contributor they tended to go down a bit, if Feb was a colder contributor, they went up. For 1734 I took a weighted average since there was no daily data. I added those values to tables above. 1957 went up a few ranks as its Feb wasn't very mild compared to most.

[Summer Sun]

10.1c to the 4th

2.2c above the 61 to 90 average
2.4c above the 81 to 10 average