Tragic London storm marked slide into WW1

May 31, 2014 wansteadmeteo Leave a comment

Over the years significant weather events have, at least in my subconscience, at times signalled that something ‘big’ is about to happen – just one example being the Great Storm in October 1987 that was followed days later by the Black Monday stock market crash.

So an event that happened 100 years ago this month, to some, probably also brought a feeling of impending doom as the political situation in Europe became ever more fraught.

Account of the thunderstorm reported in The Times

A series of severe thunderstorms that broke out just after midday over south-west London on June 14, 1914, left people dead and a trail of destruction across areas south of the Thames. Fierce lightning, torrential rain, severe flooding and hail ‘the size of walnuts’ accompanied the storms. Six people were killed by lightning on Wandsworth Common and four others were injured. As with many thunderstorms the heaviest rain, 94mm in 3 hours at Richmond Park, was focused over a small area. South Kensington, just over 5 miles away, recorded just 6mm! I don’t have the figures for Wanstead but judging by the map published in the 1914 edition of British Rainfall it probable recorded even less than South Kensington.

Some reports by observers.

Dulwich: Violent hailstorms. Many hailstones were like acid tablets about one inch long, half an inch broad and over a quarter of an inch thick. A minute or two after these had fallen, a mist rose to a height of about 4ft above the ground.

Lewisham: A storm began at 12.24pm and came right overhead from the east with terrific flashes of lightning and loud thunder. At 12.31pm, rain fell with extraordinary fury; within 9 minutes 0.5 inches had fallen. The second storm came up just after 1pm, the lightning being even more severe. At 1.30pm, St Mark’s Church, and the Holy Cross were struck. A tree in Hither Green cemetery over 30ft high was splintered and two houses were struck at Catford. Another thunderstorm came up at 2.25pm with torrents of rain and hail as large as haricot beans fell for 5 minutes.

Rainfall in the London area - June 14, 1914 - shown in the publication British Rainfall — Rainfall in the London area – June 14, 1914 – shown in the publication British Rainfall

Richmond Park: Very severe storm passed over the house; an oak fence was struck by lightning in two places. Rainfall measurements were as follows: 1.80 inches in 45 minutes, 2.70 inches in 90 minutes, 3.2 inches in 2 hours, 3.60 inches in 2.5 hours, 3.70 inches in 2.75 hours.

Wimbledon Downs: There was a curious scene close to Kingston station, where the water was about 4ft feet deep at five o’clock and motor cars and omnibuses had to make a wide detour. The storm was especially severe in Wimbledon district, where, owing to the bursting of an overtaxed sewer, the District Railway line was submerged. At Tooting Junction station was a foot deep on the platform.

Judging by the 1881-1910 average 1914 was a warm year: the mean temperature of 10.7C was a full degree warmer than average. It was also 15 per cent wetter than average and the sun hours were nearly 108% of average. Of course by today’s standards (the 1981-2010 average) 1914 looks relatively cool as the average annual temperature has risen 1C in the past hundred years.

The weather on this day must have been synonimous with the deteriorating political situation in Europe: two weeks later Franz Ferdinand, Archduke of Austria, and his wife Sophie were assassinated in Sarajevo by a young Serbian nationalist Gavrilo Princip , the casus belli of the First World War.

What is fascinating is that a similar thunderstorm that left seven dead in Valentines Park, Ilford, 75 years ago this August, also happened about two weeks before Prime Minister Neville Chamberlain announced on September 3, 1939, that Britain was at war with Germany.

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Events, History, Weather

50 years of London heatwaves

May 16, 2014 wansteadmeteo 1 Comment

Ask a dozen people what they think is a heatwave in this country and you’ll probably get 12 different answers.

The view across to St Paul's Cathedral from Bankside at low tide by Scott Whitehead — The view across to St Paul’s from Bankside at low tide.

The UK press is always keen to tell us that a ‘heatwave is on the way’ – even if it is March and the heatwave in question brings temperatures no greater than the high teens Celsius.

Although in the UK there is no official definition of a heatwave the World Meteorological Organization description is “when the daily maximum temperature on more than five consecutive days exceeds the average maximum temperature by 5 °C, the normal period being 1961-1990”. In other words that March heatwave would see the thermometer peak higher than 15.3C five days in a row. Pleasant enough – but no big deal.

The Met Office, working with the Department of Health, provides a ‘Heat-Health Watch System’ for England which is triggered when a threshold temperature in the South East is 31 °C by day and 16 °C overnight for at least two consecutive days.

I have vague memories of the weeks of sunshine in 1976 but the hot spells that stick in my mind the most are August 1990, when the UK temperature record was set in Cheltenham, Gloucestershire, and August 2003 when an 8-day hot spell saw the all-time UK temperature record broken when 38.5C was reached at Brogdale, near Faversham, Kent.

Last July, when compared with the previous summers, saw some of the best summer weather since 2006. But where does last year compare with the good summers of 2003, 1995, 1990 and 1976? I decided to have a look back at the daily records for this area which stretch back to 1959.

I have drawn up a list of all days back to 1959 that have an average mean daily temperature of 23.5C or higher. This shows that there has been 93 such days. However, to qualify for the Met Office’s Heat-Health Watch System – ie two days like this in a row the list narrows. To make my job easier, I have narrowed the list further to 3 consecutive days where the mean has been 23.5C or higher. Though I loathe really hot weather in my experience I can put up with it for a couple of days. It is only when it gets to the third day of hot, sleepless nights that it starts becoming unbearable.

In terms of intensity and hours of sunshine, 2003 comes out on top. Though many people will argue that 1976 is more impressive -that summer, which comes in second, only produced two spells that satisfy my criteria. The first heatwave saw temperatures soar above 31C for six consecutive days from June 23. The start of the second, on July 3, saw Bjorn Borg win the first of five Wimbledon mens’ titles as he prevailed over Ilie Nastase in 35C heat.

The summer of 1995, which saw my driest-ever August with just 0.7mm of rainfall all month, comes in 3rd, with six days of mean temperatures of 23.5C or higher.

Polo advert for the heatwave that coincided with the Queen Mother's birthday in 1990 — Polo advert for the heatwave that coincided with the Queen Mother’s birthday in 1990

Looking at the data another way, ranking the average total daily mean temperature of each spell, sees 2003 again come out 1st, with August 1990 and July 1983, 2nd and 3rd. Looking back through history it is not really surprising that 2003 comes out on top. While it was hot in London the heatwave across the Channel contributed to the death of over 70,000 people throughout Europe, France being the most affected.

This weekend promises to be very warm and sunny but it will pale into insignificance compared with the hot spells of the past. The mean temperature on Saturday and Sunday is unlikely to exceed 17C.

Forecast, Weather

Summer forecast: barbecues and umbrellas

May 7, 2014 wansteadmeteo 3 Comments

At the beginning of May I had a look at the March and April stats to try to decipher what the coming summer would be like. The results still suggest that summer will be a mixed bag weather-wise with only brief hot spells interspersed with humid thundery breakdowns and cool, cloudy and showery regimes.

The third warmest March-April period since 1799 possibly prompted some weather ‘experts’ to claim that we’re heading for a hot summer. But converse to what the Daily Express told us in April I cannot see any signs of a ‘hottest summer ever’. And it should be remembered that this rag also warned us that the past winter would see ‘100 days of snow’. In the event I think 100 days of rain was probably more true, and I would like to point out at this juncture that my own winter forecast was hopelessly out, along with many others.

To reach my conclusion on this summer I have used pattern matching of meteorological data for March, April and May stretching back to 1799. The mild and dry weather of March and April has been tempered by the wet May. The mean for the spring season was 11.7C with 116.4mm of rain and 473 hours of sunshine. If you take into account all years that were within +/- 10 per cent of these figures you get the following table.

When considering the data I first extracted the number of similar years by rainfall. Of these I then discounted any that were not within + / 10 per cent of the spring 2014 mean temperature.

The ‘best fit’ years were revealed as 1811, 1828, 1871, 1882, 1912, 1945, 1959 and 1989. Using sun hours similarities this could be narrowed further to 1912, 1945, 1959 and 1989, however it should be noted that I don’t have sun hours data prior to 1881!

As an average this summer could be expressed as:

Mean: 17.3C (about average) Rainfall: 186.1mm (slightly above average) Sunshine: 583hrs (slightly above average)

Or, expressed in probabilities, I concluded the following:

So from the above you could deduce that the next three months will be average to rather cool, with average to slightly below average rainfall. Sunshine below average.

Trying to predict details over the next 3 months is impossible, but looking at the ‘best fit’ years mentioned above a warm spell happened without fail between the dates June 18th – June 22nd. Other dates to bear in mind for possible fine spells are July 5th, July 12th-15th, July 22nd, August 4th and August 20th.

* Taking into account the fact that temperatures in London are up to 1C warmer than they were 100 years ago I have added 1C to mean temperatures before 1915.

** Obviously, in the event of a series of direct hits from thunderstorms, my rainfall estimate could be hopelessly short – a symptom of abundant solar energy at this time of year which creates a ‘noisy’ atmosphere compared with winter.

*** The 1981-2010 average mean for summer in this region is 17.6C, with 144.9mm of rain and 564 hours of sunshine

monthly summary, Weather

April 2014: Another mild and dry month

May 1, 2014 wansteadmeteo 3 Comments

April 2014 continued this year’s theme of being milder than normal; the mean temperature of 12C was 2.2C above average, making it the third warmest April since 1797.

Though many days were stunningly sunny the breeze made it feel chilly

April continued the dry theme of March and was indeed dryer on average. Just 19.6mm on rain fell over the 30 days – that’s 46 per cent of average.

The month saw some stunningly sunny days during the second week into the third week, though these were tempered by chilly east to north-easterly winds. The warmest day was the 21st when 21.5C was reached – the first ^70F temperature of the year.

Though it ‘felt’ quite a sunny month the 150 hours recorded was only 94 per cent of average.

Some nights were chilly when the sky cleared but there was no air frost and only two ground frosts, on the 15th and 16th

To view full stats follow this link:http://1drv.ms/1cBRoH3