The author of The Last King of Scotland talks to McKinsey’s risk expert about his novel about the D-Day landings. The fate of 2.5 million men, 3,000 landing craft and the entire future of Europe depends on the right weather conditions in the English Channel on a single day. A team of Allied scientists is charged with agreeing an accurate forecast five days in advance. But is it even possible to predict the weather so far ahead? And what is the relationship between predictability and turbulence, one of the last great mysteries of modern physics?