This play is about James Stagg who was in overall charge of predicting the weather for the D-Day landings. He had four days in which to provide his advice, and was up against a successful American forecaster, who already had the ear of the Supreme Commander, Dwight Eisenhower.
You may quail at the thought of any play being based on a weather forecast, the main prop being a pressure chart of the Northern Atlantic, and all the action being in a sparsely furnished room, the few props being weather recording instruments. Sure, there is a romantic story about Ike’s relationship with Kay Summersby, his car driver, who was also his lover and general therapist, but this is a play about the difficulty of communicating science.
Since this is a London play ending at the close of August, I doubt my explanations will spoil anything for most of you, but it is a lovely story about the dilemmas of being an expert witness. Whatever the cost, or the pressure to give the desired answers to power, predictive accuracy is the scientific goal, and James Stagg stuck to his guns, on the basis of a gut feeling about imperfect data, guided by a general three-dimensional model for which he had only partial support.
David Haig wrote the play, and takes the part of James Stagg. Malcolm Sinclair is a very convincing General Eisenhower and Laura Rogers a charming, long-suffering Kay Summersby. All the players were excellent, so one can suspend belief and just enjoy the story.
James Stagg had to explain that in his view all forecasts based on historical records were dubious, and all forecasts based on air pressure charts were flawed because they were two dimensional. He had to explain a recently observed phenomenon (which all of us now take for granted) based on two pilots who reported that they had completed their flights from America to England particularly quickly, because at high altitude they had benefited from a very high tail wind of about 130 miles per hour. This was, as the American forecaster pointed out, a very small sample.
Stagg argued that this jet stream, as we now call it, would pull in the Atlantic storms to the Channel on the intended D day of 5th June. The American argued that the fast moving northward good weather from the Azores would triumph, and that the jet stream was an irrelevance in the general picture. After frenzied discussion the invasion was postponed, possibly for weeks, with potentially lethal military effects because the element of surprise would be lost and the deception plan rendered useless, since there were few practicable days when the tides were favourable. Stagg thought he could see a one day pause in the storm, so Eisenhower took the gamble, and the invasion took place the following day, 6th June 1944.
The attraction of this story should be obvious to all researchers. It was an instance when history turned on a complex point of meteorology, and the supposedly supreme command was subservient to the weather. It is not often that governments ask for true advice, and unusual that they want the real answer, even if it is highly unpleasant. War is a hard taskmaster. Of course, it has another parallel in the climate change debate: who does one trust to make the correct predictions, in this case for events that may take decades to be tested?
Will a government ever ask psychometricians for advice, and change policies as a result? In my view that is highly unlikely. So, it is entertaining to find that at least one weatherman had his day in court and changed the course of history.