"TO inform, to educate and entertain" was the mission of radio as a broadcasting medium, according to the first director general of the BBC, John Reith. Echoing these sentiments with irony, the American news commentator Ed Murrow declared the purpose of television to be "to distract, delude, amuse and insulate". Meteorologists on this side of the Atlantic, however, aspire more to the former model than to the latter, in their role as television weather forecasters.
The television era began for meteorology in 1936 when the first weather maps appeared on BBC television. An anonymous hand pointed out the fronts and isobars on the hand drawn chart, and a disembodied voice read the detailed forecast to the accompaniment of light music.
Techniques had improved considerably by the time weather forecasts first appeared on Telefis Eireann in the early 1960s. The forecaster was then in full view, standing beside a pair of boards assembled like a sash window. The weather maps were drawn on the boards in felt tipped pen: having carefully explained the details of the "Today" chart, the forecaster would "open the window", so to speak, on tomorrow's weather by pushing the first chart up and out of view to expose the second to the camera.
Meanwhile, the BBC had progressed to magnetic symbols. They were similar in shape and meaning to those we know today, but were clutched in a little bundle by the forecaster, and dexterously deployed over the island of Great Britain. The system stood the test of time, even if the symbols slipped occasionally to show a thunderstorm descending rapidly from John O'Groats to Plymouth much to the amusement of the viewing public.
Today's TV charts are electronically prepared entirely on computer screen, the forecaster using an electronic pointer to choose the appropriate lines and weather symbols, and to instruct the computer where to put them an outline map. Also available in electronic format to be added to the picture are the appropriate satellite and radar images. When the forecast goes on air, all this information is drawn directly from the computer and combined electronically with the image of the forecaster on camera.
This means, of course, that the chart which appears behind the presenter does not, in fact, exist at all. When the forecaster indicates a deep depression over Dingle, he or she is really pointing at a silver backdrop which remains entirely blank throughout: imagination and experience suggest the appropriate place for him or her to indicate, and an adjacent television monitor confirms if this is right.