Technological Advancements in Forecasting

From Traditional Charts to Computer Forecast Models

When George Cowling became the first television weatherman in 1954, he was assisted by a great deal of experience and scientific understanding, some statistically-developed 'rules' and little else. His main tools were pencils (and a rubber) for analysing the charts plotted by his assistant, and a pair of dividers for measuring isobar spacing to give wind speeds. He actually worked at the London Weather Centre - then in Kingsway - and had to transport a large bundle of rolled charts across London to the BBC's Lime Grove Studios in Shepherd's Bush.

One of the first technological developments was the receipt of charts via a large fax machine. The modern era arrived for forecasting when the first electronic computer was installed at Met Office headquarters, then in Bracknell, in 1962 and the first operational guidance from this computer, increased the accuracy of the forecast.

In 1964 the first operational pictures from satellites became available but it was not until 1973, when a new and more powerful computer producing a detailed 10-level numerical model of the Earth's atmosphere, caused the biggest single increase in accuracy, doubling that of the three-day forecast. Information was now arriving regularly from satellites and the forecaster's world was expanding.

The first Met Office supercomputer, the CDC Cyber 205 was installed in 1981, and a 15-level atmospheric computer model was introduced. Further developments, included the installation at Met Office HQ of two Cray Y-MP super computers (one of the world's largest computers) in 1990 and 1991, allowing the introduction of a new 19-level model and improved representation of atmospheric processes. Both machines were replaced by a single Cray C90 in May 1994 with a six-fold increase in the speed of processing. Then in 1996 a Cray T3E supercomputer was installed, five times more powerful than the Cray C90, followed by a second T3E in 1999.

These huge improvements in processing speed and computer power, have continued to improve the accuracy of the weather forecasts. Some measures of accuracy show an improvement from 79% before 1980 to 86% in 1996.

In 2004 the Met Office introduced its next supercomputer made up of 30 NEC SX-6 nodes running at its new HQ site in Exeter, providing six times the power of the current supercomputers.

Computer Graphics Systems

In parallel to the improvements to forecast data accuracy, the equipment used by the TV forecasters has also changed enormously from that used by George Cowling. Much of the forecast information they need to interpret arrives directly to their computers, enabling them to customise the information they need to see on screen. A bespoke graphics system allows them to easily create bulletins tailored to the channel, the platform and the audiences.

In the studio, they stand in front of a blue-washed screen (green can also be used) for the presentation, and control the whole broadcast themselves, calling up pre-programmed graphics which are added to the TV picture by computer.

In 1993, the BBC Weather Centre won the Royal Television Society's award for Technical Innovation in operational systems. But developments have not stopped and improvements in both broadcasting and computer technology are continually being incorporated to upgrade the system.