D Minus Months: Strategic Planning for Weather-Sensitive Decisions

General Eisenhower’s decisions to postpone and, one day later, to launch the “D-Day” invasion of Normandy are a gripping illustration of sequential decisions under uncertainty, suitable for any introductory decision analysis class. They’re also the archetypal example of weather-sensitive decision making using a forecast. This paper develops a framework for analyzing weather-sensitive decisions with a focus on the less-familiar strategic decisions that determine how forecasts are produced and what operational alternatives are available so that decision makers can extract value from forecasts. We tell the story of the decisions made in the months before D-Day regarding how to set up the forecasting process and the myriad decisions implicating nation-level resources that prepared Allied forces not just to invade, but to hold open that decision until the last possible hour so that Eisenhower and his staff could use the critical forecasts. Finally, we overview the current state of the weather-forecasting enterprise, the current challenges of interest to decision analysts, and what this means for decision analysts seeking opportunities to help the weather enterprise improve forecasts and to help operational decision makers extract more value from modern weather forecasts.