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Whether the Weather for D-day
Whether the Weather for D-day
By John E. Ross
More than 130,000 soldiers, 7,000 ships, and 12,000 aircraft participated in D-day, the largest amphibious assault in history. Fewer than 5,000 troops were killed during the landing. Landing at low tide, D-day soldiers avoided most beach obstacles placed by Germans to wreck their landing craft.
On the night of 5 June, 1944, the incessant drone of aircraft after aircraft carrying paratroopers and towing gliders bound for Normandy and D-day reverberated over Southwick House, SHAEF’s advanced headquarters a couple kilometers inland from the Royal Navy’s massive base at Portsmouth.
Sweethearts Jean Farren and Harold Checketts, naval ratings who plotted weather maps for SHAEF, were returning to their quarters after attending a birthday party in town. Hearing the planes, Jean began to cry, terrified she’d made mistakes on her weather maps and had helped send thousands of men to their deaths.
In 2011 when I interviewed them, now married, at their dinner table for the book The Forecast for D-day and the Weatherman behind Ike’s Greatest Gamble Jean started to tell the story. Then her voice faded, she bowed her head and dissolved into tears. Such was the pressure she and her colleagues had been under when making the most fateful forecast in history.
Had D-day failed, at least 12 months would have been required to launch a new invasion of northern France. World War II would likely have been prolonged in Europe for a year.
If so, the western Allies would have joined up with the Russians at the Rhine instead of the Elbe in central Germany. Result: no West Germany. The most effective units of French resistance were the communists. Given an additional year, the communists would have earned enough public support to dominate the French National Assembly when France was liberated. Result: no NATO. Imagine our world history over the past 75 years without NATO.
The fulcrum for making an accurate forecast lay largely across the shoulders of SHAEF’s chief meteorologist, James Martin Stagg. Stagg was a geophysicist at heart who had risen through the ranks of Britian’s civilian weather bureau, the Met Office, into the role of coordinating meteorological services for the Army as the war began.
In keeping with SHAEF’s protocol of appointing Englishmen as senior commanders of air, land, and sea and Americans as their deputies, Stagg’s deputy was USAAF Col. Don Yates. Together, their responsibility was to meld forecasts from three different weather “centrals,” the US Strategical and Tactical Air Force, the Royal Navy, and the Met Office. The three used different methodology and never agreed!
Weather data was provided by Met Office stations throughout the UK, weather ships and weather reconnaissance flights over the Atlantic, resistance units in occupied countries, and intercepted German radio transmissions. The latter were instrumental in breaking the German’s much vaunted Enigma code.
In addition, though the Republic of Ireland was officially neutral, its weather service. Met Éireann provided data to the Met Office. Observations taken by Maureen Sweeney, a postal clerk on Blacksod Point in far northwestern Ireland would be of critical importance in the forecast for D-day.
At 2130 Double British Summer Time (DBST) on 3 June, SHAEF’s supreme commander, Gen. Dwight Eisenhower, was meeting with his senior commanders to decide whether to launch the invasion on the following day as originally scheduled.
Though skies were mostly clear with gentle winds barely ruffling the leaves outside of Southwick, Stagg stood before the group and reported that 4/5 June would see “disturbed conditions in the Channel and assault area.” Winds could reach Force 5 and cloud would be low and thick.
These conditions were far worse than minimums set for D-day: wind about 11 mph, surf no greater than 6 to 8 feet, and light cloud. If Stagg’s forecast for high wind and low cloud was correct, paratroopers would be wildly scattered, bombers could not hit their targets, and landing craft would be swamped. On this report, Ike decided to postpone D-day until better weather was forecast.
During the following night’s supreme commanders’ meeting at 2130 DBST, the weather was as foul as the previous night’s had been fair. Gusting winds drove heavy rain against Southwick’s windows. Stagg reported that this vigorous cold front with would likely pass over the channel and Normandy during the night with variable periods of cloud and diminishing wind for the next few days. Stagg, as was protocol, then left the room and waited in the hall.
A little while later Ike came out and to his weatherman said, “Well Stagg, we’re putting it on again; hold the weather to what you’ve told us and don’t bring any more bad news.” D-day was formally launched on the night of 5 June.
The vast invasion involving 1.5 million troops, 142,000 vehicles, 12,000 aircraft, 16 million tons of supplies, and 7,000 ships with 195,000 sailors was set in motion. Two weeks later on the alternative dates with low tides and partial moon, the worst storm in 40 years swept through the English Channel.
Said Eisenhower later, “I thank the Gods of War we went when we did.”
Copies of The Forecast are available at Middleburg Books.
