THE VERY DIFFICULT BIRTH OF THE WEATHER FORECAST
AS A nation we’re obsessed with the weather and rightly so. And the gravest consequence of failing to predict a change in the weather isn’t just being caught without a brolly during a downpour. At least five ancient civilisations were felled by inclement weather and wars, governments and food production have historically been at the mercy of the elements.
The first published weather forecast in the UK appeared in 1861 and was 100 per cent accurate, if rather broad brush. But over the past 30 years forecasts have become so precise they can target postcodes, allowing residents to plan a barbecue in one locality or an evening in with a box set in another just a couple of miles away.
This fascinating evolution is traced next week in a new radio programme, Rain Or Shine? A Short History Of The Weather Forecast on the BBC World Service. Experts explain how scientists, sailors, mathematicians and inventors helped turn weather prediction from “witchcraft” into a respected, profitable and vital modern industry.
The story includes the tale of the most important weather forecast in history and the improbable role of the J Lyons tea house chain in the evolution of meteorology.
Let’s start in the Middle Ages, a time when weather prediction was mainly limited to shepherds scrutinising the skies. But monasteries and the growing University of Oxford began to take an interest with a view to developing an ability to warn of health crises and crop shortages. In time they got it right about 50 per cent of the time and the first meteorological instrument – this one to measure humidity – was produced in the 1600s.
THE sea change – literally – came in the 1830s thanks to Admiral Robert FitzRoy, the man who captained HMS Beagle, the vessel that took the naturalist Charles Darwin on his epic fiveyear voyage around the world.
FitzRoy began making weather observations from the deck and was the first person to use the phrase “weather forecasting” – probably inspired by “forecastle”, the forward point of a ship.
Back on dry land, FitzRoy set up what was to become the Met Office in 1854. He had a staff of three and utilised the new electric telegraph to collate weather reports sent in by observers. As BBC weather man Peter Gibbs says in Rain Or Shine?: “Weather systems span thousands of miles and are changing all the time. You need instant snapshots of the weather at any one time to be able to make predictions.”
FitzRoy gave instruments for recording the weather to ships’ captains and combined this with historical data to compile wind charts. Merchant ships could then plot speedy and safe routes, saving money and lives.
The big step, in 1861, was to make his predictions available to the general public through newspapers and his reputation was such that Queen Victoria once asked him for a forecast to cover her journey to the Isle of Wight.
He began posting gale warnings at ports which annoyed fishing fleet owners as it led to their boats being grounded periodically, a loss-making practice they sought to subvert by preventing publication of the notices. Bedevilled by depression, problems at the Met Office and destitution after spending all his money on public affairs and failing to recoup it, a desperate FitzRoy cut his own throat.
In recognition of his efforts the Queen offered his widow a graceand-favour apartment at Hampton Court. He also died a hero to fishermen and, in his name, they fought and won the right to have storm warnings displayed once again.
Weather reporting also played a significant role in the two world wars of the last century. The term “weather front” – meaning the weather that arises along a narrow zone where warm air meets cold – came from the zones of trenches in the First World War.
It was coined by Lewis Fry Richardson, a pacifist and Quaker, who was attached to an infantry division as an ambulance worker. The uncle of actor Ralph Richardson, he is also the great uncle of Julian Hunt, now Baron Hunt, who ran the Met Office in the 1990s.
While the importance of the weather for troop movements has been recognised for millennia, it took on a make-or-break significance when the D-Day landings of 1944 were being planned. Weatherman Peter Gibbs explains: “They needed days around the full moon to get the light, low tides coinciding with dawn so German coastal defences could be exposed, clear skies for aircraft operation and calm seas, especially for amphibious landing, which is a big ask. The weather forecast was going to be crucial.”
General the value Eisenhower of weather had seen prediction earlier in the war and two meteorological teams were set to work. An American team looked back over 50 years of weather charts to find similar weather to that which they were currently experiencing and from that data worked out what would happen in a few days’ time.
They suggested June 5. But the British and European team using Polar Front theory (looking at where cold air meets warm air, which causes weather changes) said something was developing in the Atlantic which would cause problems on June 5, so they recommended a delay until June 6. They were right. Gales and heavy cloud cover appeared on June 5 and while conditions the next day were not perfect they were good enough.
In 1950, the first computergenerated weather forecast was produced in the US. But it took 24 hours to come up with a forecast for the next 24 hours, so it was of limited use and required a million multiplications and divisions to be performed. In London, the Met Office borrowed its first computer from the catering company J Lyons, which had developed the LEO – the world’s first business computer. The Met Office didn’t buy a computer of its own until 1959.
Weather forecasts were drawn up in the offices of the Air Ministry and the computer-generated scroll taken by taxi to the BBC’s Lime Grove studios. By the 1980s the Met Office computers still had only 20 per cent of the capacity of today’s smartphones and so perhaps it is time to forgive Michael Fish his “There’s not a hurricane on the way” forecast of October 1987, which was swiftly followed by the biggest storm in 300 years.
LAST year, the Met Office took delivery of a super computer, which can make 14,000 trillion calculations per second. But to generate predictions, it must input weather observations from the 300 weather stations around the country. And as the mathematician and meteorologist Edward Norton Lorenz observed in the 1960s, it only takes a slight change in the values input to produce a radically different prediction. He called this the butterfly effect, saying that the flap of a butterfly’s wings in Brazil could set off a tornado in Texas.
Peter Gibbs explains how today meteorologists try to get round this by ensemble forecasting (a method used in numerical weather prediction): “We slightly change the starting conditions and keep doing this 40 or 50 times. If the results are fairly similar, we can be confident. If they diverge it could mean the atmosphere is volatile and could change.”
Which is why even today’s ultrasophisticated weather forecast can never be 100 per cent perfect. Just don’t blame the weather presenter.
The Forum: Rain Or Shine? A Short History Of The Weather Forecast can be heard on the BBC World Service tonight at 8pm or on Tuesday at 9am and will be available online at bbc.co.uk/worldserviceradio