April 2018 C.E.T. forecasts and optional EWP contest

[Radiating Dendrite]

We hit 26.3c here yesterday and had a day average of 17.7c. 

Central London (16 miles down the road), briefly touched 29c! Certainly confirms the point that 30c is possible in April, if this spell had been 10 days later we could have got it.

[Relativistic]

3 hours ago, Radiating Dendrite said:

We hit 26.3c here yesterday and had a day average of 17.7c. 

Central London (16 miles down the road), briefly touched 29c! Certainly confirms the point that 30c is possible in April, if this spell had been 10 days later we could have got it.

Indeed, for me it's a matter of when and not if. That's twice now in recorded history that 29C has been breached before the 20th.

It's entirely plausible that places hit 30C on 29th April 1775.

Edited April 20, 2018 by Relativistic

[BornFromTheVoid]

With the CET data updating rather inconsistently, it looks like we have the first provisional record of the warm spell. Old record for the 18th was 14.5C. With a min of 11.8C and a max of 21.6C this year, we have new provisional record of 16.7C. For now, that's the 6th warmest April day on record.

[Summer Sun]

9.5 to the 19th

2.2 above the 61 to 90 average

1.7 above the 81 to 10 average

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Current high this month 9.5 to the 19th

[The PIT]

Sunny Sheffield up to 8.3C +0.7C above normal. Rainfall unchanged. A smaller rise for today and another for Saturday. Then it should slow down perhaps drifting slightly down or up. Rainfall unchanged.

[DAVID SNOW]

On ‎18‎/‎04‎/‎2018 at 10:48, BornFromTheVoid said:

As we embark along this impressive April warm spell, a couple of record may come under threat.

1: Most number of days with a CET of at least 15C - the previous record was 4 from 2011. The current forecast has us achieving a run of 5 consecutive days of at least 15C, starting today.
Over the CET record, 15C+ days occur on average just once every 5 years. The longest stretch without was 24 years, from 1902 to 1925.

2: Most number of days with a CET of at least 16C - the previous record was 3 from 1795. The current forecast has us achieving 5 days of at least 16C.
Over the CET record, 16C+ days occur on average just once every 18 years. The longest stretch without was 53 years, from 1950 to 2002.

3: Most number of days with a CET of at least 17C - the previous record was 2 from 1795. The current forecast has us achieving 3 days of at least 17C.
Over the CET record, 17C+ days occur on average just once every 82 years. The longest stretch without was 169 years, from 1776 to 1944.

4: The warmest April week on record was the final 7 days of 1795, which averaged 15.1C. The current forecast has the week of the 16th to the 22nd average 15.6C

I'll add some more as I find the time!

Don't think the 15C was achieved today and going by the GFS, as we do, Saturday and Sunday wont make it either.

[Summer Sun]

9.7 to the 20th

2.3 above the 61 to 90 average

1.9 above the 81 to 10 average

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Current high this month 9.7 to the 20th

[The PIT]

Sunny Sheffield up to 8.6C +0.9C above normal. Rainfall unchanged.

[Roger J Smith]

Odd that the monthly estimate is updating but no daily estimates for 19th or 20th. The increase was 0.4 for 19th and 0.2 for 20th (from 9.1 to 9.5 to 9.7).

Think this can only be valid if the 9.5 was 9.46 or so, and the 9.7 could be 9.74 so the actual changes are more like +0.33 and +0.28, which would be consistent with values like 18.0 and 17.0. This would imply the past two days were 2nd and around tied 4th warmest April days on record. In any case even if we knew the provisional values, only the final numbers count in this regard. 

[Weather-history]

It's going to be a bit of an odd month, a warm April and a wet April rarely go hand in hand. 

It looks likely it will be the wettest April for England and Wales since 2012

 

[Scorcher]

On 4/20/2018 at 20:33, DAVID SNOW said:

Don't think the 15C was achieved today and going by the GFS, as we do, Saturday and Sunday wont make it either.

Surprised you're so sure about that- Stonyhurst, which is the often the coldest station, hasn't dropped far below 15C overnight. The min is likely to be very high and the southern stations are going to have another very warm day.

[Summer Sun]

9.9 to the 21st

2.5 above the 61 to 90 average

2.0 above the 81 to 10 average

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Current high this month 9.9 to the 21st

[Relativistic]

2 hours ago, Scorcher said:

Surprised you're so sure about that- Stonyhurst, which is the often the coldest station, hasn't dropped far below 15C overnight. The min is likely to be very high and the southern stations are going to have another very warm day.

It's a bit odd, Hadley haven't updated the estimated mean values since the 19th, but they have updated the estimated minimum and maximum values. If you calculate the mean values based off those you get 13.9C and 13.8C for the 20th and 21st, respectively.

Edited April 22, 2018 by Relativistic

[The PIT]

Sunny Sheffield up to 8.8C +1.1C above normal. Rainfall  up to 77.3mm 122.3% of average. Looks like temperatures may rise for a few more days before temperatures return to average values which should result in a small slow drop.

[The PIT]

22 hours ago, Weather-history said:

It's going to be a bit of an odd month, a warm April and a wet April rarely go hand in hand. 

It looks likely it will be the wettest April for England and Wales since 2012

 

Well cold and very wet months don't normally go hand in hand either.

[Weather-history]

36 minutes ago, The PIT said:

Well cold and very wet months don't normally go hand in hand either.

You mean like last month? I was specifically referring to Aprils rather than generally. I think you will find that a warmer season month is more likely to be cooler or indeed cold when it's also very wet than a winter month.

 

 

 

 

[damianslaw]

Have to say this April is turning into a notably very mild one for the south at least - I can't help but think the effects of the SSW have been a prime reason, a sluggish jetstream has remained in place and instead of March, the southern half of the UK has been on the warmer side of the polar front jet preety much all month so far. Given the effects of the SSW, perhaps no surprise to see it ending up quite at the more extreme end temp wise, it could have gone the other way and been a notably colder month.

There is a chance we may end up with a value 3 degrees above the norm, on a par with 1987, 2007 and 2011. However, as others have said, it hasn't felt anywhere near the likes of those months, which brought consistent dry settled sunny conditions. This month has been far wetter and duller so far and the outlook is far from settled. 

For the northern half of the Uk temps look like ending up nearer the norm, and won't be remembered for much other than the short burst of warmth on Thursday/Friday.

[Roger J Smith]

So about this question of warm/dry and cool/wet, most of the warmer Aprils appear to rank in the dry third of the spectrum, 2007 was seventh driest (1766 to 2017) and 2011 was 9th, third warmest April 1865 was 32nd driest. Many of the other really dry Aprils had near average CET values indicating a less southerly sort of blocking in place, the mean of the six drier than 2007 was 8.6 and this included one warm April, 1893 (10.3). The two driest Aprils (1938, 1817) were both a rather chilly 7.6.

At the other end of the spectrum, most of the wet Aprils were below or average in CET. Going from wettest up the rankings, the first one that achieved even 9.0 C was 12th wettest 1800 (9.3) and the wettest one to make 10.0 was 17th wettest 1961.

 these are the ranked 10 driest and wettest according to the Hadley series from 1766 to 2017 with their CET values indicated. 

Rank ____ Dry Apr __ CET _____ Wet Apr __ CET

_ 01 _____ 1938 ____ 7.6 _______ 2012 ____ 7.2

_ 02 _____ 1817 ____ 7.6 _______ 2000 ____ 7.8

_ 03 _____ 1912 ____ 8.8 _______ 1782 ____ 5.2

_ 04 _____ 1957 ____ 8.9 _______ 1818 ____ 6.9

_ 05 _____ 1893 ____10.3_______ 1998 ____ 7.7

_ 06 _____ 1785 ____ 8.4 _______ 1829 ____ 6.7

_ 07 _____ 2007 ____11.2_______ 1920 ____ 8.2

_ 08 _____ 1984 ____ 8.1 _______ 1882 ____ 8.4

_ 09 _____ 2011 ____11.8_______ 1846 ____ 7.8

_ 10 _____ 1854 ____ 9.2 _______ 1966 ____ 7.2

mean CET of these __ 9.2 ________________ 7.3

 

Now, here's the arcane weather trivia factoid with which you can dazzle your family and friends ...

Every World Cup of football/soccer held after a very wet April has been won by a country (a) playing at home and (b) bordering on the Channel.

Cause and effect? I think so (more strenuous training conditions, greater fitness). Am I kidding? No. well yes I am. 

(the third wettest world cup year was 32nd place 1970, Cup played in Mexico and won by Brazil).

[Summer Sun]

10.1 to the 22nd

2.6 above the 61 to 90 average

2.1 above the 81 to 10 average

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Current high this month 10.1 to the 22nd

[The PIT]

Sunny Sheffield up to 9C +1.2C above normal. Rainfall 77.6mm 122.8% of normal.

[DAVID SNOW]

Going by the latest GFS, perhaps a drop to around 9.3 by months end.

[Summer Sun]

10.1 to the 23rd

2.6 above the 61 to 90 average

2.0 above the 81 to 10 average

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Current high this month 10.1 to the 22nd & 23rd

[The PIT]

Sunny Sheffield up to 9.1C -1.2C above normal. Rainfall unchanged. GFS out on it's own later on this week so what actually happens is slightly up in the air. However it looks like any increases will be due more to mildish nights.

[Mapantz]

2.3°C above the average here. Sat at 11.1°C

[DAVID SNOW]

2 hours ago, The PIT said:

Sunny Sheffield up to 9.1C -1.2C above normal. Rainfall unchanged. GFS out on it's own later on this week so what actually happens is slightly up in the air. However it looks like any increases will be due more to mildish nights.

This evenings ECM also showing cool temps to the end of April, as ever only time will tell.