April sunshine totals 1981-2010

Figure 1

The sunniest place on average in the UK in the period between 1981 and 2010 is Shanklin on the Isle of Wight with 201.4 hours. In fact most of the climate stations in the top 17 can be found on the English Channel coast somewhere. On the southwest peninsula the fall off in sunshine the further away from the coast you are looks to be around 10%. The Met Office provide these 1981-2010 average in their DataPoint web service and are not neither straightforward to download or to parse, because they’re all in XML format and come as individual files for almost 300 locations. The things I have to go through for a climate story.

Figure 2

I contacted the Met Office at Jersey yesterday and asked them what their record highest April sunshine total and got this tweet back.

Figure 3

I make their total for the same period 249.5 hours, yesterday they had another 2.5 hours taking them up to 252.0 hours. I’ve tweeted the Met Office at Jersey and asked them to check their total, but so far have had no response. As far as I can see I’ve done the maths correctly, and my old maths teacher Mr Brightmoor I’m sure would have been proud of me. The 1981-2010 average for Jersey is 196.5 hours in April, so that makes the latest anomaly just over 28% above the average.

Figure 4

A sunny month in the south and east

Figure 1

A very sunny month especially across more southern and eastern areas of both Scotland, Wales and England, but always cloudier the further northwest that you went, and more generally over Ireland (fig 1). The sunshine figures are for some reason always more reliably reported in a SYNOP report from a AWS than are rainfall totals, as you can see from the Rx column (fig 2) most stations are at 100%. Jersey is still miles out in front this month, with over 240 hours of sunshine, being an Island in a relatively cold English Channel does help a bit in that department. There are several other chasing stations who also might crack the 200 hour barrier this month, and today might help in that regard at Camborne.

Figure 2

These sunshine totals are high but they don’t look high enough to beat the April of 2015 which was exceptionally sunny across the country (fig 3). ‘Sunniest since 2015’ doesn’t make much of a headline I’m afraid.

Figure 3 – Data courtesy of the Met Office

The Met Office do provide monthly climate statistics for Jersey, so it looks like this April they are currently around 122% of the average, with four days left of the month. I’ve Tweeted the Jersey Met Office to try and find out if they know what the sunniest April on record there, hopefully they will reply, and not by Tweeting ‘yes we do but we are not telling you’.

Figure 4 – Courtesy of the Met Office

Jersey the sunny Channel Island

Figure 1 – Courtesy of vintagerailposters.co.uk

Jersey have taken over at the top of the sunshine league this April, with almost 9 hours of sunshine each day for the first 20 days of the month. Their total of 178.6 hours so far is I estimate 66.1% of the possible maximum total. It’s not been sunny everywhere across the British Isles, but without detailed climate statistics to produce anomaly values it’s impossible to be precise, but as usual, it seems to have been duller the further west and north that you are so far this month (fig 2).

Figure 2

April 2017 – Weather World

Figure 1 – Courtesy of Armagh Observatory

I’ve just watched another interesting installment of Weather World on the BBC and noticed from the credits that it was written by Nick Miller. He and Sarah Keith-Lucas hosted the proceedings that were centred at a number of locations in Northern Ireland:

  • Belfast International Airport – Aldergrove to you and me, and saw why weather is so important for aviation at airports.
  • Ulster Aviation Society Museum – where they looked at the history of ‘weather flights’ across the Atlantic.
  • Armagh Observatory – and saw how observations are made today, and at their long running climate recordings, which started on the 27th of December 1794.

I’ve changed some sunshine cards in my time at a number of stations across the UK, some of the locations that the recorder was sited were far from ideal, but the observatory at Armagh as a novel approach to getting around the problems of trees getting in the way, the sunshine recorder sits in a lift like device that raises and lowers the old Campbell-Stokes sunshine recorder what looks like 50 foot into the air (fig 1), I hope after that platform doesn’t affect the wind speeds that they measure from the anemometer up there though. They take their weather observations very seriously at Armagh!

At a 24 hour station you could always change the sunshine card late in the evening, it seems strange to see it being changed at 09 UTC in the morning, there were times that someone forgot to change the card, or on very wet days the card almost disintegrated because it was so wet.  Seagulls also liked to attack the cards for some reason, and then there was the perilous job of checking the previous shift’s sunshine card, was that a continuous burn or not, and just when did you start or stop measuring the trace at sunrise and sunset?

I like Sean Kelly the weather observer at Armagh, he’s been doing the job for the last 18 years, and seems to have the right attitude to technology, they’ve tried automatic weather stations in the past, but found that they weren’t reliable enough. That’s what we said in the Met Office for over 30 years, we had a good run for our money but in the end we were replaced by an AWS, try getting a job as a weather observer at the Jobcentre now, Sean might well be one of the last one of us left here in the UK. Nick explained about how observations are taken each morning at 9 o’clock, “this weather ritual that has been happening for over 200 years” he said, except for last Tuesday when it looks like they had a day off (fig 2).

Figure 2 – Courtesy of the BBC

Given the brief from the producer, and the time constraints of the program, Nick Miller did a pretty good job in getting his story across, Sarah Keith-Lucas came across as a really nice person that I’m sure she is. Interestingly they kept it to just the two of them, and wisely in my opinion, didn’t include any input from the ubiquitous Carol Kirkwood. It’s possible that the BBC have decided to use Nick Miller for these kind of programs in favour of John Hammond from now on, and maybe that’s the reason why he decided to take an early shower.

April in pictures

Images courtesy of the Met Office and EUMETSAT

Here in Devon, we just about got away with five consecutive sunny days at the start of this April, but even today it’s still very pleasant, and unofficially the air temperature is around 17.5°C at 15 BST. A number of stations won’t be that far short of a 100 hours of sunshine in the first 11 days by close of play today I would have thought, Lyneham most certainly will have a ton up (fig 2).

Figure 2

Sunny start to April

It’s been a very sunny start to April 2017. In the first eight days Lyneham in Wiltshire is top of the sunshine league in this part of NW Europe with 78.3 hours of bright sunshine, which I make as 73.9% of what’s possible, and a daily average of almost 10 hours. Unfortunately the further west and north that you went the cloudier the month has been. The ‘Rx’ column by the way indicates the percentage of reports received, which is out of my control.

Another beautiful spring day across the south

Figure 1 – courtesy of the Met Office

Another lovely sunny morning down here in Devon again this morning – the third in a row (fig 1). Not wishing to rub it in at all after David Braine’s warnings of a cloudier Thursday down here for yesterday, I noticed that Exeter airport was the sunniest spot in the whole country with 12.6 hours of sunshine, ~94.6% of the maximum (fig 2). We must be in top gear making up for the dull March we had.

Figure 2

Last night was clear and starry, and led to a very cold night with a minimum of 0.0°C at the airport (fig 3), I wonder if he forecast that?

Figure 3

I suppose this is not at all surprising when you’re sat under a large anticyclone like we are at present, and as it pulls away later today we will find warmer air pushing up from France for the weekend. So we could end up with a run of five sunny days before it’s all swept away early next week.

April 1938 – probably the most anticyclonic month on record

Figure 1 – Data and Images courtesy of The Met Office, CRU & Wetterzentrale

There’s no doubt about it April 1938 was quite an extraordinary month across the British Isles. Not only was it the most anticyclonic April on record, it was also the most anticyclonic* of any month in the objective LWT series that started in 1871 (fig 4). Mean anomalies for the month were in excess of +16 hPa above the 1918-1947 long-term average across northwest Ireland (fig 2 & 3), and according to the MWR for the month :

Mean pressure markedly exceeded the average throughout the British Isles, the excess at 7h. ranging from 10.6 mb. at Lerwick to 16.7 mb. at Malin Head. The mean pressure over Scotland as a whole was the highest recorded in the month of April for at least 80 years. At Oxford the mean pressure was the highest for April since 1881 and at Southport the mean pressure was the highest in April since record were first taken in 1871.

(Courtesy of the Met Office © Crown Copyright)

I’m so pleased that the anomalies I generated for the month from the NCEP reanalysis data match the anomalies reported in the April 1938 MWR. NOAA doesn’t make things easy with their 6 hourly MSLP reanalysis data which is on a 2.5° x 2.5° grid back to 1948, but before then (from the 20th Century Reanalysis project) is on a finer 2° x 2° grid. This makes the file sizes much larger to download (~35 mb), and required changes to the code to handle both grid sizes, it also explains the strange LTA period of 1918-1947 that I’ve used in the anomaly chart (fig 3).

*I calculate a simple anticyclonicity index for the month by scoring the LWT for each day. Pure anticyclonic scores 1, while a hybrid anticyclonic type scores 0.5, add them and calculate a percentage of the maximum possible, and hey presto you have a simple anticyclonic index. You could of course have used the mean daily vorticity for the month that the objective LWT data series also produces.

Figure 2 – Data Courtesy of NCEP/NOAA Reanalysis

Figure 3 – Data Courtesy of NCEP/NOAA Reanalysis

I’m slightly concerned about the number of pure ‘A’ types in the objective LWT series from the CRU (fig 4). A few of the days look like they may have been better classified as more of a hybrid anticyclonic type rather than a pure anticyclonic type, take the 30th for example. Should that be an AE or ANE type perhaps rather than pure anticyclonic? Of course it’s impossible to be definitive about this though, because the objective LWT is derived from 12 UTC reanalysis data and the Wetterzentrale charts are generated using 00 UTC data. Going back to the original ‘subjective’ LWT data that Hubert Lamb developed, and who was the final arbiter on, and that scores an anticyclonicity index of 68.3. Who knows perhaps Lamb was being a bit hard on April 1938, especially in the first week. I will investigate this a little more.

Figure 4 – Data courtesy of CRU

It goes without saying that such an anticyclonic month was also very dry across the whole of the British Isles. Using the UK gridded rainfall data it was the driest April in the whole series that started in 1910 (fig 5).

Figure 5 – Data courtesy of the Met Office

Using the EWP series it was the driest April since at least 1766 when the series started (fig 6).

Figure 6 – Data courtesy of the Met Office

Sunshine was well above average in all western regions, but closer to average in eastern areas and the North of Scotland. The MWR says that Valentia Observatory had a total of 262 hours, the largest total for April in a record which started in 1880. It goes on to say that at Mallaranny, in County Mayo (notice how we didn’t exclude the Irish Republic back in 1938), they recorded 129.6 hours from the 8th-18th inclusive which is a daily mean of 11.8 hours for 11 consecutive days.

Temperatures were also above average in the west, but closer to average in eastern districts. Because I use the very warm 1981-2010 LTA to generate the anomalies for the April 1938 graphic (fig 1), all regions look rather cold, which just goes to show you just how misleading statistics can sometimes be.

Dull month so far in the southwest

 

Figure 1

A sunny Saturday makes a welcome change down here in deepest, dullest Devon. Hopefully in the next few days there will be a lot more sunshine to help redress the balance as March draws to an end. As you can see from the table (fig 2), in the first 24 days of March the Isle of Tiree in the inner Hebrides tops the list with over 114 hours of bright sunshine, with Exeter, Camborne and Liscombe at the foot of the table with less than 50 hours.

Figure 2

Dull start to March in the southwest

The first half of March has been disappointingly dull in the southwest of England and Wales. Camborne has only recorded 30.4 hours of bright sunshine, in comparison Boulmer in the northeast of England tops the list with 76.5 hours.

The same Atlantic feed of cloud that made the southwest of the UK so cloudy and dull has also affected much of northern and central France, whilst in comparison many places in Iberia have already clocked up well over 120 hours of sunshine already this month.