The most important weather forecast in history
In memory of my father Hans who, in 1944, took part in the liberation of Europe with the Royal Engineers in the Italian Campaign. –Benny Peiser
1) The Weather Forecast That Saved D-Day
Christopher Klein
Years of detailed planning went into the D-Day invasion on June 6, 1944, but success hinged on one element that no military commander could control—the weather. In the days leading up to the invasion, Allied meteorologists delivered the most important weather forecast in history. If they got it wrong the Allies might have lost tens of thousands of men and World War II might have been lost forever.
In contrast to the bright morning about to dawn over Portsmouth, England, on June 4, 1944, gloom settled over the Allied commanders gathered inside Southwick House at 4:15 a.m. Years of preparation had been invested in the invasion of Normandy, but now, just hours before the launch of D-Day operations, came the voice of Group Captain James Stagg urging a last-minute delay. As Operation Overlord’s chief meteorological officer, the lanky Brit was hardly a battlefield commander, but the ultimate fate of D-Day now rested in his decision-making.
The disappointed commanders knew that the list of potential invasion dates were only a precious few because of the need for a full moon to illuminate obstacles and landing places for gliders and for a low tide at dawn to expose the elaborate underwater defenses installed by the Germans. June 5, chosen by Allied Supreme Commander Dwight Eisenhower to be D-Day, was the first date in a narrow three-day window with the necessary astronomical conditions. The massive Normandy landings, however, also required optimal weather conditions. High winds and rough seas could capsize landing craft and sabotage the amphibious assault; wet weather could bog down the army and thick cloud cover could obscure the necessary air support.
The critical, but unenviable task of predicting the English Channel’s notoriously fickle weather fell to a team of forecasters from the Royal Navy, British Meteorological Office and U.S. Strategic and Tactical Air Force, and as D-Day approached, storm clouds brewed inside the meteorological office. Observations from Newfoundland taken on May 29 reported changing conditions that might arrive by the proposed invasion date. Based on their knowledge of English Channel weather and observations, the British forecasters predicted the stormy weather would indeed arrive on June 5. The American meteorologists, relying on a differing forecasting method based on historic weather maps, instead believed that a wedge of high pressure would deflect the advancing storm front and provide clear, sunny skies over the English Channel.
Stagg, the only meteorologist allowed direct contact with Eisenhower, had to make the final call. Although the sky was clear and wind negligible in the early hours of June 4, Stagg believed foul weather was only hours away. He sided with his fellow British colleagues and recommended a postponement. Knowing that the weather held the potential to be an even fiercer foe than the Nazis, a reluctant Eisenhower agreed in the early hours of June 4 to delay D-Day by 24 hours.
On the other side of the English Channel, German forecasters also predicted the stormy conditions that indeed rolled in as Stagg and his fellow Brits had feared. The Luftwaffe’s chief meteorologist, however, went further in reporting that rough seas and gale-force winds were unlikely to weaken until mid-June. Armed with that forecast, Nazi commanders thought it impossible that an Allied invasion was imminent, and many left their coastal defenses to participate in nearby war games. German Field Marshal Erwin Rommel even returned home to personally present a pair of Parisian shoes to his wife as a birthday present.
German Luftwaffe meteorologists, however, relied on less sophisticated data and models than their Allied counterparts, says John Ross, author of “The Forecast for D-Day: And the Weatherman behind Ike’s Greatest Gamble.” “The Allies had a much more robust network of weather stations in Canada, Greenland and Iceland; of weather ships and weather flights over the North Atlantic and observations by secret agreement from weather stations in the neutral Republic of Ireland,” he says. Those weather stations, in particular one at a post office at Blacksod Point in the far west of Ireland, proved crucial in detecting the arrival of a lull in the storms that Stagg and his colleagues believed would allow for an invasion on June 6. As rain and high winds lashed Portsmouth on the night of June 4, Stagg informed Eisenhower of the forecast for a temporary break. With the next available date for an invasion nearly two weeks away, the Allies risked losing the element of surprise if they waited. In spite of the pelting rain and howling winds outside, Eisenhower placed his faith in his forecasters and gave the go-ahead for D-Day.
The weather during the initial hours of D-Day was still not ideal. Thick clouds resulted in Allied bombs and paratroopers landing miles off target. Rough seas caused landing craft to capsize and mortar shells to land off the mark. By noon, however, the weather had cleared and Stagg’s forecast had been validated. The Germans had been caught by surprise, and the tide of World War II began to turn.
Weeks later, Stagg sent Eisenhower a memo noting that had D-Day been pushed to later in June, the Allies would have encountered the worst weather in the English Channel in two decades. “I thank the Gods of War we went when we did,” Eisenhower scribbled on the report.
He could also have been thankful for Stagg overruling the advice of the American meteorologists who wanted to go on June 5 as planned, which Ross says would have been a disaster. “The weather over Normandy contained too much cloud cover for Ike’s greatest strategic asset, the Allied air forces, to effectively protect the landings from German armor, artillery and infantry reserves. Winds were too strong for the deployment of paratroopers to secure bridges and crossroads inland from the beaches thus preventing German reinforcement of coastal positions. Waves were too high for landing craft to put soldiers and supplies ashore. The key element of surprise—location and time—would have been lost, and the conquest of western Europe could well have taken another year.”
2) D-Day: The Sceptical Meteorologists Who Surprised The Nazis By Saying ‘Yes’ To June 6
Simon Pearson
The outcome of D-Day was decided not on the beaches of Normandy, but by weather systems in the mid-Atlantic and the ability of rival teams of meteorologists to interpret the forces of nature. The Americans were confident in long-range five-day forecasts. The British were sceptical, believing they could forecast only two days ahead at best. The teams clashed repeatedly.
The outcome of D-Day was decided not on the beaches of Normandy, but by weather systems in the mid-Atlantic and the ability of rival teams of meteorologists to interpret the forces of nature.
As unfavourable conditions developed during that early summer 70 years ago, three teams of meteorologists produced reports for the Allied commander, General Dwight D Eisenhower, who laid down the conditions necessary for invasion — and his preferred date: June 5. Across the Channel, a single team of Germans watched the weather.
One of the men who took part in this great drama was Lawrence Hogben, a New Zealand naval officer, who, as a Rhodes Scholar, studied mathematics at New College, Oxford and trained as a meteorologist with the Royal Navy. Today, he lives in a care home in southern France, the country he helped to liberate and, even at the age of 98, retains vivid memories of events in June 1944.
Hogben had already distinguished himself as a naval officer before he was asked to work with Geoffrey Wolfe, a Cambridge-educated engineer, in the Admiralty team forecasting the D-Day weather.
As an instructor lieutenant, responsible for training, intelligence and meteorology on HMS Sheffield, he had witnessed several major naval actions: the sinking of the German battleship Bismark in May 1941; the Battle of the Barents Sea — when Sheffield engaged the German pocket battleships Admiral Hipper and Lutzow in the Arctic in December 1942; and Operation Torch, the invasion of French North Africa a year later.
Decorated for bravery and promoted instructor lieutenant-commander, he had also developed his skills as a weatherman. “OnSheffield, I was making forecasts every day from the data coming in and from the state of the sea,” he says.
Hogben and Wolfe were one of two British teams. The second, put forward by the Met Office, consisted of Charles Douglas, the chief forecaster who was known for his photographic memory of meteorological events, and Sverre Pettersen, a Norwegian. The third team was American, with Irving Krick and Benny Holzman, two well-known weathermen from the California Institute of Technology. Each day, the three teams reported their findings to Group Captain James Stagg, a Scot who had been superintendent of the Kew Gardens observatory in 1939. He briefed Eisenhower.
For operational reasons, the American commander needed a full moon, a low tide, little cloud cover and light winds so that troops in landing craft could get ashore quickly, the gliders and parachutists could operate efficiently, and the Allied fighters and bombers could find their targets.
The forecast was not good. Indeed, climatic data suggested the odds against the forecasters finding the right conditions was 13-1 in June 1944. The Americans were confident in long-range five-day forecasts. The British were sceptical, believing they could forecast only two days ahead at best. The teams clashed repeatedly.
According to William Bryant Logan, author of Air: The Restless Shaper, they succeeded, “not because of the brilliant work of any solitary forecaster, but because a group of forecasters imitated the weather. They jostled, yelled, scribbled, and cast malevolent looks at one another. They fought it out and voted. And in the end, they were just right enough.”
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The Belorussian campaign, Operation Bagration, launched on June 22, was designed to take advantage of D-Day, the “Second Front” so long called for by Stalin (who had already been helped by Allied operations in North Africa, Sicily & Italy).
Bagration (aka the Destruction of Army Group Center) didn’t need D-Day to succeed. It was a set-piece inevitability following on from the Ukraine battles that exposed the southern flank. No other result was plausible at the time. Even had LIII Corps made it out of Vitebsk, it would have been rounded up with the rest of 4th and 9th Army in the pocket around Minsk.
With Vasilevsky and Zhukov on the job, given the depolyments and doctrines in place, the writing was on the wall for Army group Center months before D-Day. The only thing that might have prevented it would have been the evacuation of Army Group North from the Baltic and a flatfront withdrawal to the Berezina. And that simply wasn’t in the operational cards.
evanmjones says:
June 6, 2014 at 12:44 pm
You’re right that Hitler made it impossible for AG Center to mount a sane defense, but it’s also true that the Wehrmacht lacked the armored forces it needed for counter-attack because they were being held in the West to oppose the invasion of France, & had been moved there in expectation of the landings.
As you know, the Red Army paused on the Vistula to let the Germans destroy the Polish Home Army in its Warsaw Uprising, in August to October.
Those WWII veterans left who read this, thanks. We owe you.
milodonharlani says:
June 6, 2014 at 12:30 pm (Edit)
Only if doctine had been handed over to the Wehrmacht. Which was not a happening thing. Even if they had defeated the initial invasion, Heersgruppen B & D would have had to remain largely intact in France. Besides, thanks the the NRO, the Germans had lost all operational initiative.
The overall strategic situation of HG North and Center was hopeless to the point where no number of reinforcements would have turned the tide — there would have just been that many more prisoners in the Bagration op.
Yes, there would have been more for the Russian front had there been no WAllied presence on the ground. But I don’t think it would have made any material difference. Not in light of German doctrine at the time. And the Luftwaffe had been badly flattened in the month before D-Day. And if the invasion had failed, the bombing campaign would still have continued, so there would have been no significant diversion to the east.
And it’s a lot further from Minsk to Berlin than from Berlin to Paris.
evanmjones says:
June 6, 2014 at 1:07 pm
About 50 miles as the crow flies, but the terrain is less favorable to the offense, unless you detour over the North German Plain, lengthening your route & making river crossings tougher. On a more direct route, you have the Fulda Gap, river valleys, hills & forests with which to deal.
Patton might not have been able to resist hitting the Russians in their vulnerable flank to cut off their advanced formations.
Just kidding. Sort of.
You’re right that Hitler made it impossible for AG Center to mount a sane defense, but it’s also true that the Wehrmacht lacked the armored forces it needed for counter-attack because they were being held in the West to oppose the invasion of France, & had been moved there in expectation of the landings.
Yes, like the IPCC, Hitler was relying far to much on Model output . . .
But what good would a counterattack have been? 3Pz, 4th, and the better half of 9th Army were beyond rescue barely a week after the operation began. And when Model did manage to crack open a corridor between HG Center and HG North, rather than extricate HG North OUT, Hitler sent two divisions IN.
As you know, the Red Army paused on the Vistula to let the Germans destroy the Polish Home Army in its Warsaw Uprising, in August to October.
That’s still somewhat controversial. But, yes, I think that is the truth of it. They followed up around Lvov, and then dealt the death blow in Rumania. Between July and September of 1944, the Germans lost as many men on the eastern front as they had during the entire war up to that point. The true crash came abruptly and quickly.
Vasilevsky was the true hero. But Vasily never gets the cred that Zuk gets, even today when we know better. Zuk even gets primary credit for Stalingrad, when in reality he was getting the snot kicked out of him around Rzev (Op. Mars). But for Vasily, who co-planned — and carried out — the battle of Stalingrad? Nothing. (And don’t be telling me Mars was a “diversion”. That’s commie propaganda. Mars was supposed to be the main event — with Stalingrad as the diversion.)
evanmjones says:
June 6, 2014 at 1:26 pm
Model was if anything even less useful than the models.
Staff weenies only get credit if they carry out the plan as well as make it, like Manstein. Or maybe Wedemeyer, although his plan for cross-Channel invasion in ’43 was given the kibosh.
Thank God we had the Germans on our side, like Ike, Wedemeyer & Nimitz. Not to mention Oppenheimer & Einstein.
About 50 miles as the crow flies, but the terrain is less favorable to the offense,
One has to consider that once Berlin is taken out, the rest of the way to Paris will no longer be seriously contested.
As much as I admire Patton, if he had been as injudicious as to take on the Sovs, there would likely have been a second Dunkirk. The beastly Sovs outnumbered us 5 to 1 on the ground. They did not have to supply by sea. They were (by that time) better than we were man-far-man, had vastly superior tanks (and many more of them deployed), and a tactical airforce to match the WAllies (our huge strat air being near-useless for purposes of fighting Russia at the time).
Model was if anything even less useful than the models.
He is a bit overrated, I agree. They say he used to love visiting the front, schmoozing with the frontline troops — and leaving organizational disaster in his wake. And he certainly got nowhere at Kursk (not that he really could have). But he did (arguably) almost singlehandedly save 4th and 9th Armies from encirclement and destruction during the battle of Moscow.
Thank God we had the Germans on our side, like Ike, Wedemeyer & Nimitz. Not to mention Oppenheimer & Einstein.
And von Braun, afterwards. (Not that he was a particularly nice person, or anything.)
I confess I have a wargamer’s tendency to view WII as a titanic 4-year struggle between Germany and the Soviets with a bit of unimportant stuff going on around the edges.
Not that I haven’t studied the rest, or anything.
But when I was teaching “my Russians” English as a second language, they would ask me about WWII because they knew their history was one Big Lie. I was in the fortunate position to tell them that the one thing their history did get straight was the scope of their contribution to WWII. And not to let one undereducated American lout dare to take away one iota of the glory they deserved.
Keep up the good work, I’m here in Normandy and it was cool clear and sunny.
Just packing my 92 year old father/d-day vet around to see the sights.
What they were doing, is dropping chaff, at a groundspeed of 10 knots, that looked like a huge invasion force of ships heading for Calais.
As Hitler was prone to that prejudice, this was highly effective. 15th Army (twice as large as 7th) did not get into the game for weeks as a result. This led directly to the Falaise disaster, and even the Germans had to admit the jig was up. Interestingly, it is said Patton wanted to invade at Calais, which would, in my view, have been a very serious mistake.
milodonharlani says:
June 6, 2014 at 1:32 pm (Edit)
You mentioned Fulda. That is telling. (It betrays postwar knowledge at the mudslogger-level.)
Had D-Day failed, the casualties could have been catastrophic, but the war has already been lost by the Germans on the Eastern front, on the seas, and in the skies. Meanwhile, American development of the A-bomb continued. If D-Day had failed, the first use of the bomb may have been against Berlin and not Hiroshima.
Evanmjones
Were ‘your Russians’ aware that they were allied to the Germans in the first years of the war and exchanged supplies with them?This was as a result of a non aggression pact signed in August 1939 by Stalin when they carved up Europe between the two countries. It was hitlers treachery against russia in june 1941 that caused russia to come over to the allies when they then fought with great courage and sacrifice. The numbers of Russians killed was far in excess of the rest of the allies.
Are they also aware of the tremendous allied effort to keep them supplied via the northern sea route in 1941 and 1942? My neighbour was on the convoys which he says was terrifying as regards german attacks on them, but fortunately the arctic had melted since the 1920’s which allowed the northern route to become an effective supply route. He says the Russians were extremely unfriendly and after delivery of their goods they were not allowed to stay in the city but encouraged to leave as soon as possible.Ironically years later the Russians recognised the bravery of those manning the convoys long before the British govt which took until the last year before awarding the convoy troops medals.
Tonyb
evanmjones says:
June 6, 2014 at 1:37 pm
IMO Germany west of Berlin would have been ferociously contested, if by some miracle Germany had stayed in the war, fighting the Russians while letting the British & US advance at will.
The Red Army did not outnumber the western Allies 5-1 on the ground in Europe. Ike commanded 90 US, UK & other Allied divisions. I don’t know off the top of my head how many Red Army divisions were in Europe in May 1945, but I suppose around 400 rifle & 40 tank. Each Allied division at full strength was over half again as large as a Soviet rifle division, most if not all of which were under-manned. Corps & Army level strengths were also in favor of the West. I’d like to see the actual figures, if available, but IMO ground forces would have been closer than five to one.
Correct me if wrong, but I’m going to guess some two million Western Allied ground forces in Italy & NW Europe in May 1945 to maybe five to six million Soviet effectives there, including allies, many of whom would be needed to occupy Eastern Europe.
Terrain in western Germany south of the NGP favors the defense. Without US vehicles, the Red Army would have been practically immobile, especially given a severe shortage of horses.
T-34 was overall better than but not vastly superior to Sherman (especially Firefly), not that I’m a big fan of M4 (Patton’s mistake not to recommend cutting back on production in favor of Pershing). Russians liked Sherman’s radios, for instance, which Soviet tanks lacked. And we had Pershings in the pipeline. The Red Army was down to fewer than 10,000 tanks on VE Day, about equal to the number of diesel Shermans we sent them.
Soviet tactical aviation was pretty good, but IMO would have been rapidly destroyed by ours. It wasn’t used to operating against vast air fleets of fighters & fighter-bombers, let alone medium bombers. Individual a/c were good, but lacking in important ways compared to Western equivalents, where they existed. Pe-2 & Il-2, much as I admire them, among best of class in the war, would have been sitting ducks, & Yaks & La-5/7s just would not have cut it against Western in-line & round engine fighters. General standard of aircrew & maintenance was also in WAllies’ favor.
Our strategic air force would have been far from useless. Indeed, it would have been highly useful for cutting off the Red Army in Germany from its supplies, & could be deployed against mass formations of ground troops. Our navy could have entered the Baltic & Black Seas. American artillery fuses & fire control were from another planet compared to the Russians’.
The Red Army was infinitely more dependent on supplies from us than we were from them.
The approximately two million German PoWs in Western custody would have been more eager to fight for us than those still alive in Russian hands.
Besides which, by July ’45 we had the Bomb & the means to deliver it long distances, & they didn’t.
Michael Palmer on June 6, 2014 at 9:03 am
…
Had D-day failed, the one real difference in outcome would have been that most of continental Europe would have come under Russian control. D-day was mostly about reigning in Russia, not about defeating Germany.
That made it even more important for civilization and democracy that DDay did not fail, and makes its heros doubly so.
evanmjones says:
June 6, 2014 at 2:16 pm
In another life, I was a Cold War Soviet Army analyst. My buddies were the boots & tracks on the ground covering the Gap & driving over German flower gardens on maneuvers.
I know what our battle plans, tactical, operational & strategic, were & am confident they would have worked at every level. We knew the enemy & knew ourselves. Not that I don’t have the greatest respect for Russian & Ukrainian fighting men & their leaders’ military doctrine, from which I learned much.
“””””….milodonharlani says:
June 6, 2014 at 2:33 pm
evanmjones says:
June 6, 2014 at 1:37 pm
IMO Germany west of Berlin would have been ferociously contested, if by some miracle Germany had stayed in the war, fighting the Russians while letting the British & US advance at will.
The Red Army did not outnumber the western Allies 5-1 on the ground in Europe. …..”””””
Well the Russians were not exactly lacking in some equipment.
The Sturmovik, was produced in greater numbers, than any other aircraft in aviation history.
Not such a bad machine for the time either.
george e. smith says:
June 6, 2014 at 2:47 pm
Il-2 flew low & slow. Although armored against ground fire, it would have been dead meat for US & UK fighters. Without fighter cover, it was practically defenseless, despite rear gunner, who was often a condemned man from a penal battalion. For most of the war, the Luftwaffe never had enough fighters in the East.
PS: In those instances in which US fighters accidentally attacked Russian a/c or ground forces or were attacked by the Red Air Force in 1945, the Soviets lost. Badly. The best known incidents involved P-38s over Romania. You’d think that Yaks would have an advantage in a dogfight with twin-engined, high altitude interceptor/escort fighters, but they lost, anyway, despite superior numbers.
In regard to the second half of WW2 there was no need for either the Allied leaders then, or commenters now, to have the slightest shame in admitting that it was a sensible and moral choice to deliberately let Hitler and Stalin fight it out. Shyness in the face of Russian evil was and is not needed. Stalin’s regime was the most ugly evil and viscious tyranny to ever curse humankind – far worse than Hitler. It was a towering edifice of sadistic brutality built on a towering edifice of lies and self-deceit. That the twin fascist regimes of communist Russia and nazi Germany did such damage to each other was the best possible outcome of WW2.
The Met Office’s own account can be found here http://www.rmets.org/sites/default/files/hist03.pdf
and a more personal account of some of the travails involved in getting the meteorological data can be found here http://www.oldnautibits.com/features/aerofeature5.php .
My own father was forecasting for Bomber Command’s Path Finder Force in East Anglia at the time, and he admitted that he was glad he didn’t have to do the Met Flights for D-Day, as they were arduous and dangerous.
The “model” I played (Pacific General with user-made European add-ons) proves that whatever side I was on would have won….provided reality provided a save game and redo.
Don’t forget the Man Who Saved D-Day: