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Phew, Wot A Scorcher, April!

April 20, 2018

By Paul Homewood

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https://twitter.com/metoffice?ref_src=twsrc%5Etfw&ref_url=https%3A%2F%2Fwww.telegraph.co.uk%2Fnews%2F2018%2F04%2F20%2Fuk-weather-britain-set-sizzle-hottest-april-day-70-years%2F

Excruciatingly close, say the Met Office!

Well, maybe for then, as they would love to be able to declare another record high. But the real story is not the one they would like to portray.

The record April temperature was set as long ago as 1949.

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https://www.metoffice.gov.uk/public/weather/climate-extremes/#?tab=climateExtremes

These sort of “records” are in any event pretty meaningless, other than for inclusion in the Guinness Book of Records. Weather stations come and go, while others become enveloped in urban heat islands, making long term comparisons misleading.

To get a better idea of what has been happening with the frequency of hot days in April, we need either to look at the records of long running stations, such as Oxford, or the Central England Temperature Series, which has the advantage of representing a wider area.

Yesterday, the CET registered 23.0C, which makes it the 8th hottest day in April, since daily records began in 1878:

image

https://www.metoffice.gov.uk/hadobs/hadcet/cetmaxdly1878on_urbadj4.dat

There has certainly been a cluster of warm days in the last few years. But this does not appear to be significantly different to other periods in the 1890s and 1940s.

I have no idea why these clusters should occur. But what is clear is these hot days, then as now, are nothing more than weather events.

 

CORRECTION

I originally wrote that the record temperature in 1949 had been matched in 1922 and 1944.

In fact I had misread the Met Office table, which shows the latter two as May records.

The article has now been corrected.

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35 Comments
  1. HotScot permalink
    April 20, 2018 10:47 am

    Paul

    thanks as ever. I’m an absolute dunce so graphs are invariably a mystery to me, but this one is self evident and, thanks to you, clearly explained.

    The clumping is obvious, but I’ll bet no one else can explain them either. No doubt someone will come up with a single theory and set out to prove, rather than disprove it.

  2. April 20, 2018 11:20 am

    12pm Radio Humberside news reported “Britain has run without coal for 48 hours for the first time since 18XX …due to the hot weather”
    and then large segment from Drax spokesman claiming credit .’.it was our pioneering move into biomass…’
    This week in North Lincs we have had strong strong wind all the time from Tuesday to Thursday night..so turbines have been running and sunnyish on Wed, and full sun on Thu/Fri.

  3. Phoenix44 permalink
    April 20, 2018 11:55 am

    “Clusters” are random – that’s what random looks like. If you throw a dice 600 times, you might get 100 of each number but there will be lots of clusters where you throw the same number 3 or more times in a row.

  4. Nigel S permalink
    April 20, 2018 12:12 pm

    Have they checked Brogdale? Perhaps they didn’t get the memo about leaving the tractor running by the weather station. Excruciating really gives it away. They have their cross to (polar) bear.

  5. dodgy geezer permalink
    April 20, 2018 12:18 pm

    60 year cycle? That is the obvious first thing you get out of that data. It’s the Atlantic Multidecadal Oscillation….

    • A C Osborn permalink
      April 20, 2018 12:25 pm

      Yes!!!!

  6. April 20, 2018 12:45 pm

    My perception is that this Spring has been colder than average so far, possibly in line with recent changes in the AMO. The famous AGW meme about Springs “getting” earlier may be in for a major debunking if the AMO switches back to the state it was before 1990, and Springs go back to what they were then.

    A few days of warm African plume air are irrelevant to the monthly and seasonal averages that will resolve the issue.

    • roger permalink
      April 20, 2018 1:31 pm

      My perception here in southern Scotland is that the central heating has yet to fail to kick in at some time every day.

  7. Chris, Leeds permalink
    April 20, 2018 1:16 pm

    And of course temperatures are measured with different instruments to those before the mid 1990s. Until then it was old-fashioned mercury in glass thermometers and these tended to have a ‘delay’ in registering a temperature. This meant that they gave a reading that was an ‘average’ over a period of some minutes, so the daily maximum would – in effect – have been an average over a period of minutes. The reality is that temperature fluctuates rapidly, second by second and sudden ‘bursts’ of warmth occur, as we have all felt on hot days. Mercury thermometers weren’t quick enough reacting to register these.

    In recent years the use of electric thermometers has meant that we have sensors that can and do register these shorter-term fluctuations in temperatures and each Met Service around the world has had to agree some arbitrary ‘standard’ for how frequently they ‘sample’ and ‘average’ these data to give a ‘true temperature’. In Australia their Met Service uses a sampling technique that means they ‘take the temperature’ every few seconds and average over seconds. Some have said that this accounts almost entirely for the increase in record maximum temperatures in recent years in Australia because they are measuring fluxes of heat that only last seconds. I understand that in the UK the Met Office uses a sampling that is longer than that (1 minute ie the average of 60x 1 second samples), to try and make the records that we current measure more compatible with the old days – in the US they use 5 minute averaging! Sadly – even in the last few months – an Environment Agency/Met Office diktat has abolished all remaining mercury thermometers on safety grounds. There will be no overlap of old and new methods of recording temperatures, so we will have no way of knowing how consistent our current electronic sensors are with mercury-in-glass thermometers in the same locations….

    • NeilC permalink
      April 20, 2018 4:12 pm

      At many reporting sites in the past, using mercury thermometers, there was a dry bulb themometer and a wet bulb themometer to measure the current observations. There were also a max and a min themometer, which measure the max and min temperaturs. Inside the max and min themometers there was a floating (in mercury) marker which stuck at the highest and lowest temperatures. These were reset at 0900Z and 2100Z.

      So there was no average of max and min. These were the highest and lowest for whichever 12 hour period.

      • Chris Martin permalink
        April 20, 2018 6:26 pm

        The point I was making that because they respond slowly the old mercury in glass max and min thermometers WERE averaging the actual highest or lowest temperature over a period of 1-5 minutes. Present day electronic thermometers can respond within a second and so can read a max or min that was only reached for 1 second. This means modern thermometers tend to record greater extremes. The difference in this ‘sampling’ can be 1 or 2 degrees

    • Ian G permalink
      April 20, 2018 8:43 pm

      You’re quite right, Chris. I have seen examples where AWS have recorded an 0.5C difference in the same minute. Of course, the highest temp is given as the max.
      This happens with min temps as well. However, the BOM in Australia fiddled the min temps by adjusting a low temp upwards but were caught out and had to readjust the temp back to the raw temp.

      • Chris, Leeds permalink
        April 21, 2018 8:16 pm

        Steven Burt, in his book, ‘Measuring the Weather’ quotes the example of Dodge City, Kansas in 2011. On 26th June the highest one minute temperature observed was 111F and announced as a ‘historic record’, beating the highest ever previous temperature of 110. Subsequently this was discounted because officially the US uses a ‘highest five minute temperature’, which was 110F – so the record was equalled not beaten. I am aware that there are several reports in Australia, where the BOM uses a one SECOND sampling/averaging and this has led to a number of recent heat ‘records’ in that country, whereas if they used 1 minute or 5 minute they probably wouldn’t be records.

    • Up2snuff permalink
      April 21, 2018 1:06 pm

      Chris, Leeds,
      Does that rather give the game away? They are not so interested in real scientific investigation (and being scientifically careful to cross-check measurements from modern kit with mercury thermometers) of AGW & CC but are more determined to make sure that there will continually be ‘new records’ set and that there is less means of challenging it from the Met Offices own records.

      AGW/CC will be here to stay until we are under snow for a month or two a year in southern England and London. Even then AGW/CC will be blamed for it.

      Doesn’t stop us starting to maintain a traditional max/min record in our own space of course.

  8. RAH permalink
    April 20, 2018 2:09 pm

    Meanwhile at my place in N. Central Indiana the temp was -1.966 deg. C this morning at 05:00. Our cluster this month and for the whole of this year so far is colder than average by a good bit. Chicago the first half of April was a full 10 deg F below it’s average. Detroit was more than 12 deg. F below it’s average for the same period.

    • bobn permalink
      April 22, 2018 1:37 am

      Thanks for the recording in Celsius. Im getting too old to do the math to turn ancient fahrenheit into easily recognisable anything anymore. I grew up under fahrenheit, It was confusing as hell to me as a kid – 32ish freezing and mega hundred boiling? but am very thankful for celsius taking over. As ever, we wait for the USA to reach the 19th century. Maybe they’ll adopt the decimal point soon? 7/16ths anyone?

  9. swan101 permalink
    April 20, 2018 2:34 pm

    Reblogged this on UPPER SONACHAN WIND FARM.

  10. April 20, 2018 2:40 pm

    Reblogged this on WeatherAction News and commented:
    A brief glimpse of warmth which frequents our shores in April every now and then. Old Met Man Bruce has the 18th as the warmest in CET, which looks to be from high min values – wonder how UHI affected that value?
    http://www.xmetman.com/wp/2018/04/19/warmest-18-april-since-1772-in-central-england/

  11. lloydr56 permalink
    April 20, 2018 2:43 pm

    Didn’t Britain have cold winters in the 40s? Somehow combined with warm days in April?

    • April 20, 2018 5:54 pm

      Wind direction changes can do that sometimes.

    • Ben Vorlich permalink
      April 21, 2018 6:59 am

      Not just Britain, cold in Europe too. The Battle of the Bulge Dec 1044-Jan 1945 fought in heavy snow cover. The German winter campaigns in Russia were also in colder conditions than average I think. 1941/2? and 1847 also cold, 1947 didn’t get going until the end of January and didn’t thaw until mid March.

  12. John189 permalink
    April 20, 2018 3:27 pm

    The “Phew What a Scorcher” story is essentially a non-story as no record was broken. Nor are such temperatures in April particularly rare. In 2003 on 16 and 17 April readings of 27 Celsius were common in England and Wales and even Wester Ross in Scotland got above 26 degrees. April 1984 was less hot but splendidly sunny, ditto 2007, and so on.

    Slightly off at a tangent, but relating back to earlier comments on the thread by climanrecon and roger, I too grow tired of the “spring is coming earlier every year” meme. Without trawling through records, a superficial impression is that we had a cluster of early springs in 1997-2003, but more recently 2013, 2016, 2017 and 2018 have all seen a late start to the growing season, with early May 2016 giving a fantastic show of blossoms after a cold, snowy late April, and this year’s daffodils flowering four to five weeks “late”.

    • bobn permalink
      April 22, 2018 1:42 am

      Just looking at photos of family in swimsuits in the garden at easter in 1981 in oxfordshire Uk. 20deg in april is standard in uk.

  13. NeilC permalink
    April 20, 2018 4:17 pm

    What the Met Office hasn’t said is that the year up to yesterday (19th April) Tmax is -0.9 Deg C, Tmin is -0.2 Deg C and Tmean is -0.6 Deg C.

    But nearly the hottest April day EVAH is more scary to an AGW propagandist.

    • NeilC permalink
      April 20, 2018 4:19 pm

      Sorry should have put for UK below last 20 year average

  14. Dave Ward permalink
    April 20, 2018 7:15 pm

    “Phew, Wot A Scorcher”

    I shouldn’t get too excited – it’ll be snowing by the weekend… I can guarantee it, as I’ve just removed the winter wheels & tyres from my car, and put the summer ones back on!

  15. Chris Lynch permalink
    April 20, 2018 10:06 pm

    Although they try to pretend that it fits in with their narrative it is clear that the warmists have been extremely uncomfortable with the prolonged winter and non appearance of Spring – hence their desperate hyperbole when a few hot days come along at last.

    • Gamecock permalink
      April 22, 2018 1:48 pm

      Yep. It’s another “The End is Still Near!” story.

  16. Geoff Sherrington permalink
    April 21, 2018 1:45 am

    Re fast and slow response temperature measurement devices – the BOM in Aust are saying that they have designed screens so that the electronic devices mimic the response of the LIG thermometers. It is a complicated topic that will never get resolved if LIG thermometers are outlawed. There is still alcohol in glass, though.

    But the main question I have can be posed simply, but few people seem willing or able to answer it here. Can some of you bright guys reading this state how far apart two measured temperatures need to be so that there is a low probability of them overlapping in the noise and bias? Or, put another way, what is the overall error, let’s say 2 sigma and assume normal distribution stats? Geoff

  17. donald penman permalink
    April 21, 2018 6:18 am

    The only certainty in the UK is that over the next few months the minimum temperatures and maximum temperatures as well as the mean temperatures will increase. The uncertainty regarding our summer is will it be dominated by high pressure and warm or will it be dominated by low pressure and wet. The various weather models give there predictions for the summer in the UK and May is not looking too bad but I look at the predictions for the NAO and AO which are trending more positive and think this is likely to produce stronger westerly’s and more unsettled weather, given what happened in January with the positive NAO.

  18. April 21, 2018 6:24 am

    How quick they forget the long cold winter!

    It is nice to see a couple of days of sunshine, just a shame it couldn’t have arrived a week or two earlier.

    The kids and myself were off for two week Easter holiday which was cold, wet and miserable. Did at least manage to build a new Warhammer gaming table though so not a complete wasted holiday.

    All went back to work/school this week so the sunshine is largely wasted, sods law.

    Anyway another few days of this sunshine and we’ll be getting the water shortage/hose pipe ban stories 😉

    • dave permalink
      April 21, 2018 7:01 am

      “…hose pipe ban stories…”

      The warmunista stock of pre-written, scarey, themes and memes is one reserve which will never run dry.

      Is it not time for another ice-berg to fall off, somewhere?

      • April 21, 2018 7:11 am

        And naturally the water shortage will be because of CAGW rather than the fact the population has increased by 300K every year for 20 years but we haven’t had anything like the required amount of investment into reservoirs or plumbing. 😉

  19. Colin permalink
    April 21, 2018 7:46 pm

    Anecdotal, but I nearly froze to death in Dundee week before last, temperature didn’t exceed 6°C, wind off the North Sea.
    29.1 is impressive for mid April is impressive though! It was however exceeded 70years ago, and two days earlier in the year, are we to conclude global cooling?

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