The sands of Omaha Beach and the D-Day forecast
Each Memorial Day we honor and remember the service and sacrifice so many have given to our country. I was struck by a reminder of that sacrifice by a recent study that found about 4% of the sand on Omaha Beach in Normandy was pieces of shrapnel still left from the invasion of 160,000 Allied soldiers and battle of Normandy, June 6, 1944, almost 68 years ago. That D-Day landing was postponed by one day by one of the most historic weather forecasts of all time. The invasion was originally scheduled for June 5, but 24 hours before on June 4, three teams of meteorologists, somewhat divided on opinions, recommended that the invasion be postponed for 24 hours because of a forecast of a very bad storm that day.
- Weather map of June 5, 1944
That forecast proved correct. An invasion on June 5, in hindsight, would have been a catastrophe with the rains and gale winds. The forecasting teams, one American and two British, were coordinated by Group Captain James Stagg. The forecasting teams were not in agreement about the forecast for the next day, but one of the leaders of the team from the UK Meteorological Office was a Norwegian meteorologist Sverre Petterssen
- Sverre Petterssen a Norwegian meteorological officer
who based his forecast on fundamental physics and upper air observations from Allied aircraft over the Atlantic, rather than just looking at analogous weather patterns as was the more general way of weather forecasting by the American team. Petterssen’s forecast along with other meteorologists working as a team proved correct and the break in the weather gave the D-Day landing a critical element of surprise. Within a few days, the change of tides would have meant a postponement of an invasion by a month. Two weeks after the invasion and after the Allied forces were moving forward, another fierce storm hit Normandy, but the invasion, though not in ideal weather had been a success.
Almost 25 years after contributing to one of the great weather forecasts of all time, Dr. Petterssen, was a visiting professor at the State University of New York at Albany and taught a course in synoptic meteorology.
Synoptic meteorology the analysis and prediction of storms and large-scale weather features. I was indeed fortunate to be student in Dr. Sverre Petterssen’s course that year and was reminded of it when I saw the story on the sands of Omaha Beach today.