It would be one of the most important weather forecasts ever delivered throughout history. Nearly 160,000 Allied Troops, including 14,000 Canadians, would be relying on its accuracy. The entire free world had a interest in this forecast being correct. It was the forecast for the English Channel during D-Day, the Normandy invasion, in June 1944.
Supreme Commander of the NATO forces, General Dwight D. Eisenhower needed nearly ideal weather conditions to launch the invasion. The perfect day would have a full moon, low tides, clear skies, light winds and low seas. Two such periods matched the low tide scenario, but only one had the light of a full moon, June 5, 6 or 7, 1944.
|Destroyed military equipment lies in the surf at Juneau Beach on D-Day, June 6, 1944|
It was up to the forecasters to give the best idea as to which 24-hour period would be best to launch the invasion. Early forecasts predicted stormy weather for the time frame in question. Eisenhower wanted a Beaufort Scale wind of 4 or less to give the go ahead. Force 4 winds are 13-18mph with 3.5 to 5 foot seas. Anything greater than that would swamp the landing craft and sink vital equipment. The challenges were many, so the hope was to give the landing forces the best chance possible. Any type of cloud cover would hinder air support and limit paratroopers.
|American Troops landing at Omaha Beach, June 6, 1944|
The Germans were caught by surprise, as their forecasters had told German command the bad weather would last well into June and thus prevent any invasion. The rest as they say is history with the invasion succeeding but unfortunately at a terrible cost with as many as 10,000 casualties (dead & injured), including 1074 Canadians (359 Canadian deaths). Eleven months later Germany would surrender. You can never downplay the importance of D-Day in bringing World War II to an end. One can only imagine how much worse the invasion would have gone had Eisenhower decided to leave on the 4th while the cold front whipped up heavy rain and strong winds with very highs seas and low visibility. Stagg’s forecast to travel in the relative good weather between low pressure systems on June 5, 1944 no doubt lead to the success of the invasion, as well as saving countless lives.
By the time the initial battle came to an end, the sun was shinning along the Normandy coastline.