April 2024 C.E.T. and EWP contests

[WYorksWeather]

Does anyone know what the record CET min is for tonight, and for first half of April, and for the entire month? Normally I'd go back and take a look myself, but just wondering if anyone knows as I'm a bit too tired to be bothered looking it up.

We may get a shot at breaking one or more of those records tonight, maybe?

 

[Frigid]

GFS 12Z says no to a record breaking warm April. Obviously an outlier but it's been quite a consistent theme in the runs recently for a cool down mid month. 

[LetItSnow!]

 Frigid Good! A semblance of normality would be great, please. 

[WYorksWeather]

 Frigid It was a very cold run though - near outlier territory beyond mid-month. The GFS ensemble mean does drop back close to average around mid-month though, which should at least drop the CET down slightly.

[Roger J Smith]

 WYorksWeather Record CET high min for 6 April is 10.6 in 2014 and for entire month of April 12.4 (24th, 2007). 

 

Edited April 5 by Roger J Smith

[Addicks Fan 1981]

 WYorksWeather we need @Derechoto give us an update on the ECM control as I find that a lot more trustworthy than the GFS.   

[Roger J Smith]

Not too convinced by colder trends that far out with warmer trends in more reliable short term, but took a look anyway at cases of a warm first half of April that fell away later. These are the most prolific cases, identified by a peak or at least a value above 10.0 after the 7th and before 20th, and an outcome no warmer than 9.5. I listed them in order during the daily data period 1772 to 2023. These were quite frequent in 19th century and a bit less frequent after 1900.

I also listed a few "nearly" qualifying cases. 

YEAR ____ Peak CET ___ Outcome ___ Details

1778 ____ 11.2 _ 13th ___ 8.2 _______ steady drop to end with 15th last average above 10 C.

1803 ____ 10.5 _ 17th ___ 9.1 _______ (earlier peak 11.5 2nd) _ just a gentle drop off after 10.1 22nd.

1815 ____ 10.4 _13th ____ 8.1 _______ 13.0 1st but peak for interval 7-15 listed - steady fall to 23rd, levelled off 24-30.

1826 ____ 10.0 _ 16th ____ 8.8 _______ 10.1 22nd, began to fall off sharply after 25th.

1827 ____ 10.3 _ 9th _____ 8.9 _______ lowest value 8.3 26th

1835 ____ 11.1 _ 9th _____ 8.6 _______ lowest value end of April.

1848 ____ 13.1 _ 4th _____ 8.2 _______ slow fall after still 10.6 7th, and value at end is lowest.

1850 ____ 10.2 _ 8th _____ 9.0 _______ slow decline and lowest value at end. 

1857 ____ 10.2 _ 7th _____ 7.5 _______ steady fall after 10th, and value at end is lowest.

1859 ____ 10.6 _ 9th _____ 7.5 _______ fell to 7.1 22nd-23rd.

1867 ____ 10.0 to 8th ____ 9.3 _______ was 9.2 to 9.4 11th to end.

1884 ____ 10.5 _ 6th _____ 7.2 _______ steady fall to 23rd, levelled off 24-30.

1892 ____ 10.2 _ 7-10 ____ 7.3 _______ down to 7.0 19-20, slight recovery to 7.6 25th.

1899 ____ 10.0 to 7th ____ 7.8 _______ 7.3 by 22nd - 23rd. 

1926 ____ 13.2 _ 3rd _____ 9.3 _______ slow cooling trend to mid-month (>10 to 17th), 9.1 26th lowest running CET value.

1985 ____ 11.3 _ 3rd _____ 8.3 _______ began to cool slowly 9-15 and recovered to 9.3 (19th) before a second drop.

1995 ____ 10.0 to 17th ___ 9.1 ______ 11.3 on 7th, slow fall to 18th, 9.0 several days towards end.

1999 ____ 11.5 _ 9th _____ 9.5 _______ (13.1 1st but secondary peak 9th) _ dropped below 10 on 15th, 8.7 19-21, recovered.

2002 ____ 11.5 _ 3rd _____ 9.3 _______ (10.1 to 7th, lowest value 8.3 16-17 April.)

 

did not qualify (drop was not very large)

(1894 ____ 10.6 _ 12th ____ 9.7 ______ only a small drop to 9.6 for several days 23rd-29th).

did not qualify (peak was too low or too early)

(1801____10.2 _ 4th _______ 8.3 ______ fell to 6.6 by 16th, recovered gradually (peak too early to join qualifiers.)

(1819 ___ 11.0 _ 2nd ______ 8.6 ______ slow and steady fall to end.)

(1843 ___ 10.7 _ 4th _______ 8.5 ______ fell rapidly to 7.3 by 13th, gradual recovery.)

(1930 ____10.4 to 3rd _____ 8.3 ______ fell to 7.3 22-23 April, recovered near end.)

(1974 _____ 9.9 _ 10th _____ 8.2 ______ a steady fall to end of April.)

(2008 ____10.4 _ 4th _______ 8.0 ______ fell to 6.6 by 18th, recovered gradually (peak too early to join qualifiers)

(2017 ____ 10.1 to 4th _____ 9.0 ______ was 8.8 26-29 April, an early peak and not a very sharp drop afterwards)//

1945 did not belong in this list but it can be noted that record low values occurred on 30 April after a peak running CET of 11.5 on 20th. 

CONCLUSION: It would not be all that unusual for this April to drop off into 8s eventually, or even 7s, depending on when peak is achieved (if it gets above 11 C by about 12th I would say a drop into 8s would be fairly spectacular).

 

 

[The PIT]

Sunny Sheffield at 8.7C +1.8C above normal. Rainfall 28mm 49.9% of the monthly average.

Five days in and already half the months rainfall.

[Summer Sun]

10.7c to the 5th

2.8c above the 61 to 90 average
3.1c above the 81 to 10 average

[WYorksWeather]

Definitely another rise coming today. Assuming temperatures don't creep any higher today I eyeballed the means at 15C Rothamsted and Pershore and 14C Stonyhurst. Probably just short of a daily record for the mean, but 10.6C for the 6th April minimum looks like it will go easily - no CET station got below 11C last night as far as I could tell, and it's doubtful they will before 9pm tonight given today's warmth.

[raz.org.rain]

There are signals appearing for a cooldown in mid April, but they've already been watered down by the looks of things (considering the predicted cooler and wetter spell for this week fell flat, some amount of scepticism would be warranted).

[LetItSnow!]

 raz.org.rain To be fair, early April was always looking to have a very south-westerly influence with the low pressure systems. I don’t recall thinking or people saying it was going to be particularly cool this week. 

[BlueSkies_do_I_see]

Looking like a gradual cool down come mid month. I think somewhere in the low to mid 10s C would be prime right now. There does look to be some cooler nights ahead, but nothing approaching a frost.

A 10.5C finish would tie 2020 and 1943 that currently occupy 4th/5th places.

A 10.4C would place it 6th. A temperature finish not yet achieved.

Edited April 6 by BlueSkies_do_I_see

[WYorksWeather]

 BlueSkies_do_I_see Still far too hard to say I think. The last third of the month could still bring either a notable warm period or another random northerly snap that lasts a few days. Either of which could have a huge impact.

At this stage, long range models for late April disagree quite strongly as well - the EC46 keeps the relatively cool / average mid-month trend going, whereas the CFSv2 wants to return to type with something quite a lot warmer. Of course there's always a lot of uncertainty looking three weeks ahead anyway, but I think particularly so when there's not much agreement on the way ahead.

CFS

EC46 - 22nd-29th

Edited April 6 by WYorksWeather
Added EC46.

[Roger J Smith]

Looks like a temporary peak will occur around 13 or 14 April so for those dates, top running CET values are:

YEAR ___ CET 1-13 _ CET 1-14 ___ end result

1778 ___ 11.19 ___ 10.71 ___ ____ 8.2

2011 ___ 11.18 ___ 11.08 ___ ___ 11.9

2020 ___ 10.89 ___ 10.54 ___ ___ 10.5

1926 ___ 10.59 ___ 10.47 ___ ____ 9.3

1999 ___ 10.58 ___ 10.04 ___ ____ 9.5

1894 ___ 10.42 ___ 10.29 ___ ____ 9.7

1815 ___ 10.42 ____ 9.93 ___ ____ 8.1

2014 ___ 10.35 ___ 10.31 ___ ___ 10.3

1995 ___ 10.24 ___ 10.23 ___ ____ 9.1

1835 ___ 10.15 ___ 10.06 ___ ____ 8.6

1943 ___ 10.14 ___ 10.30 ___ ___ 10.5

1865 ___ 10.05 ____ 9.99 ___ ___ 10.6

1798 ____ 9.97 ___ 10.04 ___ ___ 10.3

1792 ____ 9.95 ___ 10.16 ___ ___ 10.0

1803 ____ 9.93 ___ 10.07 ___ ____ 9.1

1827 ____ 9.90 ____ 9.83 ___ ____ 8.9

(1945 ____ 9.77 ____ 9.91 ___ ___ 10.1)

(1850 ____ 9.75 ____ 9.74 ___ ____ 9.0)

(2007 ____ 9.52 ___ 9.86 ____ ___ 11.3)

Last three are not next consecutive but of interest.

 

[The PIT]

Sunny Sheffield up to 9.7C +2.7C above average. Rainfall 34.1mm 60.8% of the monthly average.

[Derecho]

Good morning all from a windy Humberside. Yesterday's CET should come in around the mid 14s. Remaining mild today but turning little cooler briefly for midweek.

Then we get some very mild weather from the 11th to 13th with some daily CETs in the teens. The 14th may be very mild too but Stonyhurst looks set to see the colder air from the northerly come in at that point. A slower advance of the northerly will yield a higher return for this date and maybe over subsequent days too.

The EC 00z control was on the more colder side of the ensemble for that northerly but it is possible. A return to some milder weather after that sees the CET up to 10.8C by the 21st so still a long way above average. If the northerly doesn't materialise I think we have a shot of the warmest April on record as the CET could be as high as 11.7C by the 14th.

Edited April 7 by Derecho

[summer blizzard]

I suppose the bigger question then is what percentage of April's have a second half cooler than the first. Much like March there's certainly nothing forecast in terms of anticyclonic weather that would make it worthy.

Edited April 7 by summer blizzard

[Summer Sun]

11.4c to the 6th

3.5c above the 61 to 90 average
3.8c above the 81 to 10 average

[WYorksWeather]

 Roger J Smith Min for the 6th came in at 12.0C. Demolishes the date record by some margin.

Obviously 0.4C off the April record as you said (24th April 2007), but do you know if it's a warmest so early in the year record, and also which date would then surpass it if so (how much further forward you have to go in the year to find a 12.0C or 12.1C)?

[Roger J Smith]

 WYorksWeather A record of 12.1 was set on 4 April, 1926. 

As you mentioned, 12.0 on 6 April 2024 is a new record high min. Previous 10.6 (2014).

The daily mean of 14.9 was 0.3 short of record 15.2 (2011) and daily max of 17.7 was well short of 2011's 20.3 C. 

For fast comparison future records to 13 April:

07 Apr ... 18.5 (1933) ... 14.5 (1859) ... 9.5 (2014)
08 Apr ... 20.5 (1969) ... 13.1 (2020) ... 9.6 (1937)
09 Apr ... 21.5 (2017) ... 13.8 (2017) ... 9.3 (1999)
10 Apr ... 22.1 (2020) ... 14.1 (2020) .. 10.9 (1937)

11 Apr ... 21.8 (2020) ... 15.9 (1869) ... 11.5 (1981)
12 Apr ... 20.9 (2020) ... 14.5 (1939) ... 10.0 (1943,49)
13 Apr ... 19.3 (1945) ... 14.6 (1792) ... 10.3 (1939)

[WYorksWeather]

 Roger J Smith Interesting to see not much rise in the mins through April - given it's such a rapidly warming month I think you'd probably expect minima later on to be much higher than earlier on - seems that's not the case.

Useful to have the future records laid out. I think under our current pattern some of those minima may well be under threat, though on current model guidance maxima, and therefore probably means, will most likely stay out of reach.

All eyes on whether we get a mid-month northerly outbreak for the overall CET, and if so how long it lasts.

[Roger J Smith]

You would have to suppose that in late April 1775 one of the nights stayed above 13 C if those daily averages are reliable.

I suppose the slow rise in record high minima is due to greater frequencies of clear skies in warmer weather patterns going later into spring? Looking at may, the records don't exceed 14 C very often, and 15.1 on 31st (1895) is highest. 

[Summer Sun]

11.5c to the 7th

3.5c above the 61 to 90 average
4.0c above the 81 to 10 average

[Addicks Fan 1981]

 WYorksWeather I do believe regretfully that this april is following the 2007 path at the moment and considering we have been in an el niño that pattern seems to be following suit.  We all know what happened after april 2007 and it was a very unfavourable outcome weatherwise, that being said in 2007 we were coming into a solar cycle that was 30 % weaker than the previous one at the time.