D-Day: A weather forecast that changed history

US remembers D-Day 75 years later

MEMPHIS, Tenn. (WMC) - Seventy-five years ago in June 1944, Allied forces landed along the coast of Northern France as part of a military action that helped pave the way for the defeat of Nazi Germany.

Careful planning, individual bravery and, in many cases, the ultimate human sacrifice contributed to the operation, but much of the success of that day came down to the weather forecast.

That important forecast, that changed the course of history came down to a team of six meteorologists, two each from the U.K. Met Office, the Royal Navy and the United States military.

For months those six individuals worked for months honing forecasting techniques, many of which we use to this day, before advising Allied commanders, led by General Dwight D. Eisenhower, for the best time for the attack.

While on the day of the attack the Allied forces were sailing on relatively calm waters, documents released showed how bad the weather became, and how that forecast could have caused the operation to be a complete failure.

The weather leading up to D-Day became rather treacherous; the jet stream was farther south and stronger than normal, steering deep depressions past northwestern Europe in early June.

Seventy-five years ago, meteorologists did not have much knowledge of the upper atmosphere or that jet streams even existed, and there were even few observations from the Atlantic.

The Chief Meteorological Adviser to General Eisenhower Captain James Stagg and his team of six meteorologists had the difficult task of trying to forecast weather several days out, which can be a challenge,even to this day.

Reports say the initial plan was to invade the Normandy coast on June 5, but just a day earlier a unusually deep area of low pressure tracked over Ireland and then across northern Scotland with gales and heavy rain.

Gusts reportedly reached over 60 mph along the coasts in the west and north and the English Channel would have been very rough to traverse.

With the rough weather the invasion had to be delayed, the team of meteorologists were doing their best to collect new information to help plot the best surface-pressure charts to estimate the fronts currently impacting the weather.

Reports say that Captain Stagg advised that a weather window would open for June 6. Even with that prediction, there were a wide range of forecasts from the six meteorologists advising the Allies.

While the window was short, it was enough calmer conditions for the invasion to take place. Those knowledgeable with the events of D-Day say waiting a few weeks for the tides to be right, and by then, the Germans could have realized the invasion was imminent.

Reports also suggest that the end of June was again rather stormy, so delaying the day would have been no matter. In fact, June 1944 was one of the windiest of the century in southeastern England.

In the end, the course of one forecast changed the events of history, showing how important weather forecasting was and still is to this day.

Copyright 2019 WMC. All rights reserved.