Ask the Meteorologist: Why was the forecast a pivotal point in D-Day?

June 6, 1944 - a day that would become known as D-Day. It's when Allied Forces carried out "Operation Overlord" on the beaches of Normandy, France.

What some may not know is that without the forecast, history could've played out a lot differently. 

There is a movie in theatres NOW called "Pressure," and its centered around this very forecast. 

Watch the trailer for "Pressure" here.

According to the European Centre for Medium-Range Weather Forecasts (ECMWF), forecasts for June 6th were made the evening of June 3rd and confirmed the morning of June 4th. 

Forecasts for June 6th were made on the evening of June 4th and confirmed the morning of June 5th.

General Eisenhower was ready to carry out the mission on the 4th.

Instead, it was pushed back two days due to the weather. This same storm prevented the Germans from carrying out recon missions.

There was an initial storm that moved through the English Channel. This is the storm that prevented the mission from being carried out on its initial date - the 4th.

Captain J.M. Stagg led a team of weather forecasters, who said this storm would bring earlier and quicker clearing in the sky over the Nazi-controlled coast.

Behind that storm was a second storm system.

This system took its time moving across the Atlantic. That, combined with the clearing behind Storm #1, provided Allied Forces with a narrow window of opportunity to carry out Operation Overlord. 

By the time the sky cleared, it was too late for the opposition.

History often tells us that missions like this come with challenges.

In the wake of the first storm, the waves were choppy which led to Allied soldiers getting sick on approach. There was fog that limited visibility at times too.

If Allied troops didn't storm the beaches of Normandy on the 6th, the next chance would've come between June 17 and June 21. 

However, at that time, there was another storm that produced hurricane-force wind gusts and damaged several warships. 

You can see all the archived data and weather charts before and during the mission by clicking here.