The science of weather prediction

Weather forecasts are used by many different groups.  You probably check it the day before you’re thinking of going to the beach, or on holiday.  Many people have weather apps on their phones which they check daily.  There are some people, such as farmers, who have a more pertinent need for accurate weather predictions.  And big businesses use weather forecasts.  Certain types of organisations, such as airlines, buy specialist forecasts from the met office to help them to plan their activity.

Today we live in a world which surrounds us with weather forecasts, where being able to predict the future is a big money maker and people are even trying to control the weather.  But before (accurate) weather prediction, extreme weather was disastrous.  A storm in 1703 hit the west coast of England blowing cows and sheep over hedges, ships all over the place chimney stacks in London collapsed.  It’s thought that 10,000 people died in a few hours during that storm.  In the New Forest, 4000 oak trees were lost and over 1,000 seamen died on the Goodwin Sands alone.  This storm was thought to be a punishment from God and the lack of warning system meant significantly more damage was done.

A lot of this area is technical and I’m not going to get into that too much.  I want to look at how weather forecasts came to be and how weather forecasting is used.

Various theories about weather were floating around including the idea that it was cyclical, that it was to do with the moon and the planets or, as was the case for most people, that weather was an act of God.  This meant that to face the weather, you needed God on your side.  So church bells were rung during storms and prayers were made.

As time went by, science began investigating and categorising the natural world; the plants, the animals, the rocks.  But the sky lagged behind, remaining the realm of the gods.  It wasn’t until the 1800s that the study of weather really took hold.

The sky too belongs to the Landscape:- the ocean of air in which we live and move, with its continents and islands of cloud, its tides and currents of constant and variable winds, is a component part of the great globe
– Luke Howard, 1837

Despite the study of weather being fairly recent, tools for the measurement of weather had been around for a while.

  • The first tool to measure air humidity was described by Nicholas Cusa in the mid fifteenth century.
  • Galileo invented an early thermometer in the late 1500s
  • The barometer, to measure atmospheric pressure, was invented by Evangelista Torricellin in 1643.

These tools were refined between the seventeenth and nineteenth centuries, alongside other discoveries about the atmosphere.  At this time more people, although still very very few, had begun to record weather observations.  These included measurable data such as the wind direction and speed, the heat of the sun and the nature of the clouds.  When the telegraph was invented, it allowed for the sharing of these notes and would of course, later, allow for the distribution of the forecasts themselves.

Slowly, using observations and records, weather maps were drawn out and analysed.  To make the data usable, it was necessary to standardise the language and phenomena being described.  Before this point, you could describe a tumultuous wind or a feathery breeze and unless the person was there, you didn’t know you were talking about the same thing.  It was Francis Beaufort who set about to standardise wind speeds in 1806, although attempts had been made before him.  He also developed weather notation coding which he used himself in his own weather diaries:

Blue skies (b), sultry (s), hazy (h), damp air (dp), foggy (fg), rain (r), squally (sq), thunder (t) and so on
– As quoted in The Weather Experiment by Peter Moore

Cloud classification was first described by Luke Howard in 1802 and was standardised in the International Cloud Atlas in 1896.  All of this standardisation would be essential in terms of making the data usable and comparable.  It meant, that like the other older sciences, meteorology had begun the work of classifying the weather system.

By the 1860s, there was enough known about the weather to start making forecasts.  But weather forecasts were a threat to the church in much the same way as the theory of evolution had been just a few years earlier.  Forecasts suggested that mere mortals could look into the future and suggested that God was not the main driver of the weather.

However, the development of the telegraph and the expansion of the network were a boost to the new weather forecasting.  It allowed messages and forecasts to be conveyed quickly, before they were out of date, and allowed for fast transmission of observations as well.

In the 19th century, weather had important implications for shipping.  Both cargo, crew and passengers could be lost at sea, like in the storm on 1703.  To be able to map and forecast the weather would make considerable differences to traders, the navy and to passengers.

The Met Office was established in 1854 as a service to mariners and began providing forecasts to newspapers in 1861.

In the early 20th century, they focused on how to improve aviation forecasts which were becoming increasingly important, especially during the second world war.  The nature of early planes meant they were vulnerable to wind and rain so weather forecasts were vital both to the success of missions as well as the protection of the soldiers and the planes.

By the 1950s, the Met Office were producing other specialised forecasts, such as those for pigeon races, seasonal forecasts for farmers, and predicting the likelihood of train disruption from ice.  These weather forecasts were broadcast on radio and TV.  Weather phenomena which would affect aviation also continued as a major focus.

Today, we rely heavily on computer systems and mathematical mapping but we still need human involvement to interpret and judge the data.  Weather is a chaotic system and as such is difficult to pin down with any accuracy, however accurate weather forecasts have been used over and over to much success.  For example, the D Day landing was timed for a good forecast and many operations go ahead successfully today because of accurate forecasts.  It’s just we remember the ones that weren’t like the storm of 1987…

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