Nicki Household visits the Met Office and discovers that the weather is unpredictable, even with the smartest computer in Europe. If you want to ruffle the feathers of the men at the Met Office (and 80 per cent of them are men) just mention the storm of October 1987. It is still a sore point that they are perceived as having failed to forecast it.
Depending on who you ask, a variety of explanations are offered: that it was predicted, but that the calculations were 60 miles out; that the hurricane Michael Fish pooh-poohed was a different hurricane; that it was "a problem of communication"; that the forecast in question did warn of very high winds but that by the time the true direction of the storm was known, it was too late at night to warn anyone but the emergency services.
Whatever the truth, a subsequent Met Office enquiry led to "major reforms and improvements" in the presentation of weather forecasts. So, we can all sleep easier in our beds, or can we?
In olden days, the Met Office, formed in 1854, depended on telegraphed weather reports and hand-drawn charts for its forecasts. But now, with 2,000 staff (90 per cent are trained meteorologists) and the most powerful supercomputer in Europe (a Cray T3E, which processes 8,500 weather observations a day and can make 80,000 million calculations per second), it must surely be in a position to know what the weather is going to do next.
Well, not quite, admits Ewan McCallum, the head of central forecasting. The problem, he explains, is that the atmosphere is so chaotic, however clever the computer, it may not be able to predict with total accuracy, what will happen.
This is where human beings come in. Expert meteorologists examine the predictions that the computer chucks out, and only when they have compared them with the latest satellite pictures, instrument readings and local weather observations, do they make what McCallum describes as their "best shot" at an accurate forecast.
"Weather forecasting is still very much a human skill," he says. "It takes considerable understanding and experience to weigh up all the information and spot where the computer model is going wrong."
The 24-hour forecasts on BBC radio and television are now 84 per cent accurate.
A screen in Ewan McCallum's office shows him the latest satellite pictures of the earth's atmosphere at the touch of a button. While I was there, he pointed out a cyclone with a visible "eye", off the south-east coast of India. I didn't realise its significance until, 24 hours later, the radio news reported that more than 1,000 people had been killed by a cyclone along the Andhra Pradesh coast.
Although television and radio forecasts are what the Met Office is best known for, these represent only a fraction of its activities. With an annual income of Pounds 150 million, it's largest customer is the Ministry of Defence. Others include the Civil Aviation Authority, the Department of the Environment (for climate research), the Public Meteorological Service (funded by the Government), and commercial customers like Sainsbury's and Tesco, who pay to be informed in advance of cold spells or heatwaves.
Manned 24 hours a day, the Met Office's huge, open-plan central forecasting office is divided into separate areas of expertise, each with its own specialist forecasters. In the shipping section, for example, they are all ex-sea captains.
Weather information is available to anyone who asks - and pays - for it. Bookmakers can find out the likelihood of a white Christmas; the Lawn Tennis Association gets a dedicated forecast that even tracks individual rain clouds during Wimbledon fortnight; the Regent's Park Open Air Theatre is helped to time its intervals to coincide with rain showers.
Much of this information comes from local weather centres (there are 14 around the country), who combine information from Bracknell with their own expert observations. The more local and dedicated the forecast, the more accurate it can be. The 3,000 tailored forecasts a day include now-casts (0 to 6 hours), short range (6 hours to 3 days), medium range (3 to 10 days), the monthly prospect (10 to 30 days), seasonal (3 to 6 months ahead) and climate prediction (10 to 100 years). But really, or at least nearly, accurate forecasting can only be done for up to six days ahead.
Weather data arrives at Bracknell from many sources. In Britain, 250 meteorological stations measure wind speed, pressure and air temperature at hourly intervals and further information comes from 4,000 other land stations around the world, 400 merchant ships, weather balloons carrying radio sondes, aircraft, satellites and weather buoys. Every day, 10 million pieces of observational data are fed into the Met Office supercomputer.
Although the Bracknell HQ cannot accommodate school parties, its education service offers a wide variety of resources designed to make the weather more exciting to teach. Two exceptionally bright and imaginative education packs, The Weather Story for key stage 1 and The Weather Machine (Pounds 15.50 inc pp each) for key stage 2, contain simply-worded, amusingly illustrated facts about weather phenomena and the ways we can observe them, plus weather games and clear instructions on how to make simple sundials, rain gauges, wind vanes and so on.
For key stages 3 and 4, a series of 22 leaflets entitled There's More to the Weather... (Pounds 15 inc pp) cover everything from hurricanes and thunderstorms to weather satellites and forecasting. The Met Office (with the BBC) has also produced a video and teachers' pack, Images of the Earth (Pounds 47.49 inc pp, or Pounds 17.49 for pack only) for the same level.
A GCSE Project Ideas leaflet suggests practical outdoor activities, and other resources include colourful weather phenomena wallcharts, satellite posters, a rainfall map and - the latest addition - Metfax, a dial-up fax weather information for school and colleges. The Office also has a website on the Internet.
Some monthly and daily weather data from 1986-1995 is available free from the education service, though there is a charge for larger amounts. They ask that requests for data for a class project should be made by one individual and not by every member of the class.
Other data is available from the Met Office Archive, and books and videos about climate and meteorology can be borrowed from the Met Office Library. The library and the archive are open to the public.
Visits to local weather centres - there's one in every major city - can sometimes be arranged, "depending on the attitude of the manager", and meteorologists from the centres are often happy to go into schools to talk about their work and demonstrate meteorological instruments. Contact your local centre directly.
For further information and the Met Office education service catalogue, contact: The Met Office Education Service, Room 124, London Road, Bracknell RG12 2SZ. Tel: 01344 854802. The Met Office website on the Internet is at: http:www.meto.gov.uk