The Longest Forecast

In 1944 Group Captain James Stagg was given an almost impossible task by General Dwight D Eisenhower. He was asked to determine the right conditions for D-Day and to predict a day on which they’d exist.

This is his story.

May 15 1944. Hammersmith. London. D-Day -21

One by one, clutching the beautifully engraved invitations they had received over a month earlier, they all filed in to St Paul’s School in Hammersmith. Every invitation was carefully inspected by the military policemen on guard duty, every identity card checked. Admirals, Generals and Field Marshals received the same level of careful scrutiny as the lowliest staff officer or military logistician.

Nobody minded, for they all knew what they were there for. With barely a murmur the men who together represented the highest ranks of the Anglo-American conclave filtered into the school’s auditorium. The sense of anticipation was practically palpable.

At 10am precisely, General Dwight D Eisenhower, Supreme Allied Commander in Europe rose to speak.

“I welcome you,” Eisenhower said, “on the eve of a great battle.”

General Dwight D Eisenhower

Two years previously, Ike reminded them, he had been charged with a mission – to plan and carry out the Allied invasion of Europe. It was a herculean task – one that would require a combined air, sea and land assault the likes of which the world had never seen. But finally, after months of planning and preparation, Eisenhower, his staff and his men were ready to do exactly that. OVERLORD would begin on June 5th 1944.

Eisenhower now handed the briefing over to General Bernard Montgomery.

General Bernard Montgomery

Four armies, Monty explained, would assault the Normandy area of France. This presented the best compromise between distance, terrain and likelihood of success. The Pas de Calais was nearer, certainly, but it was also where the German forces, commanded by Erwin Rommel, most expected an assault to come. This didn’t mean that Normandy was undefended – far from it – but it was hoped that by means of deception and guile the Allies could persuade the enemy that the attack on Normandy was merely a diversion, with a larger attack to follow in the Calais area. This would hopefully encourage the Germans to hold back from reinforcing their forces in Normandy, buying the Allies time to consolidate their position.

Using the maps and models that littered the room Montgomery went on to explain in detail the form that the initial attack would take. In the early hours of D-Day a massive airborne assault would be launched along a wide stretch of the Normandy coast. Assisted by the French Resistance, SOE and the SAS, British and American paratroopers would blow up vital positions and seize critical bridges and towns in an effort to disrupt the German ability to respond to the coming attack. At dawn, a huge amphibious assault comprised of both infantry and armour would be launched along a fifty mile front. Five beachheads – two American, two British and one Canadian – would be seized, whilst the combined navies of the Allied powers provided fire support from out at sea. Meanwhile, in the air above, Allied fighters would assert air supremacy preventing the Luftwaffe from interfering and Allied bombers would attempt to knock out German defences and reinforcements.

With the beachheads secure, the troops would move inland and link up with the paratroopers, securing a foothold on the continent before the Germans could respond in force.

“Rommel is an energetic and determined commander.” Montgomery asserted, remembering his old desert rival, “He has made a world of difference since he took over. He is best at spoiling attack; his forte is disruption… He will do his best to Dunkirk us.”

This, Montgomery stressed, could not happen. They needed to get men off the beaches quickly, get them reinforced, and get them linked up with the airborne troops before they became isolated. If they could do this – if they could avoid Rommel throwing them back into the sea – then victory would eventually follow.

Erwin Rommel inspecting German defences.

His points made, Montgomery yielded the floor. Over the next few hours more briefings were given and questions raised and answered. As afternoon turned to evening and everyone prepared to leave, it fell to Winston Churchill to sum up the feelings of almost everybody in the room – a kind of cautious but worried commitment to the increasingly inevitable battle ahead.

“I am hardening on this enterprise.” He growled, grasping his coat lapels in his hands. “I repeat, I am now hardening toward this enterprise.”

And with that the time for talking was over. The time for action was about to begin.

May 28 1944. SHAEF Advanced Headquarters. Portsmouth. D-Day -8

Group Captain James Stagg was a worried man. This was not because he felt under-qualified to be Chief Meteorologist to the Supreme Headquarters Allied Expeditionary Force (SHAEF). Far from it. At 39 Stagg was one of the rising stars at the British Meteorological (“Met”) Office. Having started as a junior assistant at the Observatory at Kew, he had gone on to manage various facilities and field offices as well as lead polar and desert expeditions. He was also a geophysicist of some repute.

James Stagg, Eisenhower’s Chief Meteorologist

Despite this his appointment in November 1943 had caused some controversy. As a geophysicist he wasn’t, strictly speaking, a weatherman himself and this caused a considerable amount of grumbling from the genuine weathermen to be found in the British and American forces. Until very recently he had also still been a civilian, something that had not gone down well with various members of the high command.

Indeed so badly had General Harold Bull, SHAEF’s Deputy Chief of Staff, reacted upon finding out that his military meteorologists would be reporting to a civilian that he conspired to have Stagg removed from his position and relegated to the role of civilian advisor, with Lieutenant-Colonel Donald Yates appointed in his place.

Lieutenant-Colonel Donald Yates

For both Yates and Stagg this had been an awkward situation. Unlike Stagg Yates was a career military man, having already earned the Distinguished Service Medal. But he had already been working as Stagg’s deputy and both men respected the other for the differing talents that they brought to the table. Stagg’s demotion however was soon reversed. The British Air Ministry, who ultimately controlled the Met Office, were outraged at his dismissal, for when SHAEF was formed it had been agreed that the Chief Meteorologist should be British – a British Meteorologist would have a better feel for the nuances of Northern Europe’s ever changing weather systems. Stagg was thus promptly mobilised into the RAF as a Group Captain. His objection now rendered null and void, Bull backed down and Stagg was restored to command.

None of this worried Stagg though. What worried him was the weather.

May 28 1944. Senior Commander’s Briefing. Portsmouth. D-Day -8.

As Stagg prepared to deliver his now daily briefing of Eisenhower, he paused to think about what the Supreme Commander would be hoping to hear. With only eight days to go until D-Day, Ike and his staff would be looking for confirmation that the conditions were going to be right for the landings to go ahead.

Just what “right” meant in this context had taken Stagg and his staff months to determine because every element of the combined amphibious assault brought differing, complex weather restrictions into play.

The Navy, for example, indicated that surface winds could not exceed Force 3 on shore or Force 4 at sea. Any more than that and the flat-bottomed landing craft carrying the infantry would be driven off course or, worse, swamped. Winds higher than that would also cause the first wave of tanks, which were to be floated ashore from 5000 yards out using inflatable side-panels to make them buoyant, to flounder.

This wasn’t their only requirement. The tides also needed to be just right to allow mines and obstructions to be cleared, and visibility of at least three miles would be required if the battleships, cruisers and destroyers assembled offshore were to be used as artillery support. Finally, to have any hope of supplying and reinforcing the beachheads they needed the wind to remain low for at least D-Day +1 as well.

The demands of the Air Force were even greater. Fog in Britain would ground their planes completely and clouds could also cause a whole variety of problems. The fighters and fighter bombers needed a cloud base of no less than 1,000ft, whilst the medium and light bombers tasked with neutralising gun emplacements during the landings needed both a visibility of 3 miles and a cloud ceiling not less than 4,500ft. The heavy bombers meanwhile, which were intended to disrupt German reinforcements and destroy infrastructure, ideally needed no more than 5/10ths cloud cover below 5,000ft and a cloud ceiling not below 11,000ft.

Nor was that all they needed. Both Air Force and Army agreed that for the transport aircraft to find their targets they’d need at least a half-moon and a cloud ceiling at least 2,500ft over their targets. Winds could also not exceed 20mph (roughly Force 5) or the paratroopers would be unable to jump. The gliders had similar limitations. Finally, the Army pointed out that they needed the weather to be dry during and after the landing (without significant rain beforehand) else the roads and beaches would quickly become unusable.

Comparing these collected requirements with historic weather patterns in the Channel, Stagg and Yates concluded that May, June and July represented the best hope for suitable conditions. May was too soon for Ike’s assembling forces though so this meant a June invasion. Only two short periods in June would provide the right tide and lunar conditions though – June 5th – 7th and June 19th – 21st. If the weather failed to cooperate then the invasion would have to be pushed back until July, giving Rommel more time to prepare his Atlantic Wall and providing more opportunity for German Intelligence to determine both the day and the location of the assault.

Right now, standing before his Supreme Commander, Stagg was able to report that the weather was fine. The wind was quiet, the weather dry. But then came the question he was dreading:

“What’s the long term forecast, Stagg?”

May 29 1944. The Weather Hut. Portsmouth. D-Day -7

Stagg sighed. The argument had started almost as soon as the call had connected. On the end of the secure conference call were the weather centres – Widewing, Dunstable and The Admiralty. These were the centres of expertise that provided the weather forecasts which Stagg consolidated and took to the supreme command.

Widewing, were the Americans, based in Bushey Park where Eisenhower had kept his headquarters until moving his advanced staff (including Stagg) to Portsmouth ahead of the invasion. Technically Widewing was Lieutenant-Colonel Yates’ Command, but with Yates down in Portsmouth supporting Stagg the brash and charismatic Irving Krick effectively headed the team.

Dunstable were the British. More specifically, the Met Office – the nickname a reference to the fact that the organisation had moved out of London during the Blitz and were temporarily based in the small town of that name to the north of the Capital. When Dunstable talked it was normally through the measured tones of Norwegian Sverre Petterssen.

The Admiralty were the third and final weather central. More concerned with sea, swell and surf forecasting than weather specifically, the Royal Navy’s own team of meteorologists was nonetheless large enough to be considered worthy of a place at the meteorological table.

All three weather centres had access to the same data and that data was extensive, provided by the network of weather stations that criss-crossed Britain, Greenland and Ireland as well as the various ships and planes in the Atlantic tasked with reporting on the weather. All three, however, were free to reach their own conclusions as to what that data meant.

It was this that was partly the cause of the problem, for as was becoming depressingly common Widewing and Dunstable were now locked in increasingly fractious debate. The trigger for that debate had been the request from Supreme Command for a long term forecast.

Put simply, Widewing had one. Dunstable refused even to attempt one.

Such an extreme difference in opinion may seem difficult to understand, especially between two parties with access to the same data. But in 1944 weather forecasting was still more of an art than a science – and Krick and Petterssen represented two very different ideological schools of thought as to how that art should be prosecuted.

Irving Krick

Krick was a man who firmly believed that weather systems were entirely consistent and predictable. Indeed he had largely become a meteorologist with the goal of using that consistency to make money. Krick had become convinced that predicting long term weather patterns for American businesses would make him a wealthy man, and he had been working towards furthering that end when war intervened. A ruthless self-promoter and charismatic speaker, he had convinced many both in the Army and outside of it that he – and only he – could provide accurate weather forecasts. To do this he largely used the “analog method” – which meant taking the current data and finding the closest possible match for that data in the past. This, he believed, would tell you not only what the weather would be like that day, but (as he believed in the consistency of weather patterns) also what the weather would be like on the days immediately after.

Sverre Petterssen

Petterssen, by contrast, believed that Krick’s methods were not just dubious, but downright misleading. Pettersen thought that predicting the weather over a long period of time required a level of scientific knowledge and data analysis that no one had yet managed to achieve. This was not to say that Pettersen was entirely pessimistic about mankind’s ability to predict the weather at all, simply that he felt that any forecasts would always be based on an as yet incomplete understanding of the complex systems that powered the world’s weather. When combined with the conscious and subconscious experience that an experienced meteorologist built up over years of work this approach could still yield useful results, but those results could almost always only be accurate in the short term – just a few days at the most.

Both men were unyielding in their positions. Both of their respective organisations had come to reflect their particular approaches.

“Gentlemen.” Said Stagg, sharing a weary look across the table with Yates, “Can we perhaps for now just agree on what the numbers mean for today?”

On this at least Stagg was able to find some agreement, at least stretching to the next few days, and barely had the call ended before Stagg and Yates were summoned to appear before Eisenhower and his subordinates.

The weather was still good, Stagg reported, but there was, he warned, now a small risk of deterioration in conditions.

Eisenhower pressed him again for a long term forecast. How was Monday June 5th, seven days from now, looking?

“Possible or not possible?” he asked.

Stagg found himself squirming yet again for an answer. He understood why Eisenhower and his staff were asking but he also understood that they were unlikely to appreciate why he couldn’t provide a solid answer.

“At this time of the year,” he reluctantly conceded, “continuous spells of more than a few days of really stormy weather are infrequent. If the disturbed weather starts on Friday it is unlikely to last through both Monday and Tuesday; but if it delayed to Saturday or Sunday the weather on Monday and even Tuesday could well be stormy.”

Stagg stressed that this answer was based purely on generalising the weather so far in May – not on any specific data – but the assembled commanders seemed happy nonetheless. Stagg, however, could not shake the feeling that there was little real value to be found in his statement at all.

May 29 1944. Task Force 24. Coast of Greenland. D-Day -7

Admiral Edward “Iceberg” Smith was proud of his nickname. He’d earned it. He’d been at sea almost continually now since he was 23 years old, and for most of that time he’d been in or around the arctic circle.

At first it was with the Coast Guard, patrolling icy waters for ships in trouble, carrying out scientific missions and filing weather reports. When America had entered the war, however, he’d suddenly found himself in the Navy. The job was still the same, he mused – although obviously the odd pot shot at German infiltrators trying to set up their own secret weather stations on the ice around Greenland was now a feature on his “to do” list – but now he got to call himself Admiral. It wasn’t a bad deal really, he thought with a smile.

“Ready to report sir.” Said a young officer at his side, indicating that the latest weather readings could now be transmitted.

Smith nodded his approval.

The weather was changing, he thought, he could feel it.

May 31 1944. The Weather Hut. Portsmouth. D-Day -5

As Yates recounted the main discussion points of the day’s conference call Stagg couldn’t help but frown. The Group Captain had been unavailable to host the call himself so Yates had taken his place. What the American was telling him now though just didn’t seem to make sense.

Over the last two days reports and data from aerial patrols and Task Force 24 had begun to filter in, and to Stagg’s eye none of it looked good. The opposite in fact. Bad weather was coming.

Yates indicated that Dunstable agreed, as did the Admiralty. Both were now forecasting something of a black weekend.

This was very bad news indeed as Stagg had hinted at with his general comments to Eisenhower before, if bad weather hit on Sunday it was unlikely to clear up for D-Day and that meant postponement.

What was puzzling though was that Widewing disagreed completely. According to Yates, Krick and his colleague Holzman had argued vehemently that the weather would improve. The coming weather front, they insisted, would traverse the Channel very rapidly, clearing quickly and leaving good conditions for Monday’s invasion.

For a while Stagg struggled to try and see Widewing’s reasons for their optimism when both the other two centres and his own work at Portsmouth seemed to suggest the exact opposite. With Eisenhower locked in the final preparations for the invasion, Stagg’s next briefing with the Supreme Commander had been postponed until Friday. Stagg firmly believed that bringing two radically different views on the unfolding weather in the Channel to him would be disastrous. He desperately hoped there that the centres would come to some kind of agreement before then.

02:00 June 2 1944. Blacksod Point. Republic of Ireland. D-Day -3

Roughly 500 miles from Normandy on the west coast of Ireland stood Blacksod Point. Although technically neutral, since 1939 a secret treaty had existed between the Republic of Ireland and the United Kingdom allowing for the sharing of weather data. As the furthest western land-based weather station in the British Isles, this had suddenly made Blacksod Point lighthouse one of the most important locations in Britain.

Blacksod Point. Photo courtesy Evita-Coyle

This was, of course, all unknown to Tom Sweeney, Coast Guardsman and Lighthouse keeper, as he made his latest set of weather readings. The barometer was dropping, he noted. Bad weather was coming.

Having jotted down his results he made the short walk over to Blacksod village post office – the only place with a phone – so he could file them. Whilst it seemed an inconvenient situation, Tom didn’t mind. Maureen Flavin would be on duty and Tom, though he hadn’t yet told her, was in love.

June 2 1944. The Weather Hut. Portsmouth. D-Day -3

The sun had not even risen by the time Stagg and Yates entered their Nissan hut and asked the staff for the latest weather reports. They were hoping to find some kind of clarity – some definitive evidence for Widewing’s continued insistence that the weather on D-Day would be fine.

As he looked at the charts though, Stagg’s realised that it was a forlorn hope.

“In all the charts for the last 40 or 50 years I had examined,” he would later recall in his autobiography, “I could not recall one which at this time of year remotely resembled this chart in the number and intensity of depressions it displayed at one time.”

It wasn’t just the weather ships in the Atlantic now that were reporting the coming inclement weather either, as the reports from Blacksod Point showed.

Yet a few minutes later, on the morning conference call, Widewing yet again refused to modify their forecast. Indeed not only did they cling fast to their belief that high pressure was building but also now insisted that this would buffer the Channel entirely from the approaching lows and their fronts.

Dunstable was livid. What about the fall in barometric pressure reported by Blacksod Point? How could that be ignored? This suggested not only that bad weather was coming, but that on the 5th of June Force 5 winds and low-lying cloud would stream over the landing beaches, a potential disaster in the making.

Blacksod Point’s data was either faulty or an outlier, Widewing insisted. They would not modify their forecast.

The continued division placed Stagg in an enormously difficult position. With the Admiralty refusing to commit to the weather either improving or worsening, Stagg was either going to have to present a divided opinion to the Supreme Commander or pick a side.

He remained convinced that a divided opinion would be worse than useless – something that General Bull had confirmed when Stagg had hinted to him that there might be a dispute between the centres during a conversation the previous day.

“For heaven’s sake Stagg” Bull had exclaimed, more in worry than anger, “get it sorted by tomorrow morning before you come to the Supreme Commander’s conference. General Eisenhower is a very worried man.”

Stagg knew that Eisenhower’s worry stemmed from the fact that in order to meet the 5th June target date, now barely sixty hours away, the general had already began to order his men and supplies to leave their bases and head to their embarkation points. Very soon ships from ports as far away as Belfast and Scapa Flow would begin to move south to take part in the assault.

Both Eisenhower and Stagg were running out of time.

10:00 June 2 1944. Senior Commander’s Briefing. Portsmouth. D-Day -3

The weather, Stagg told Eisenhower, was continuing to deteriorate. It was still impossible to predict accurately what conditions would be like on Monday and Tuesday but the signs were increasing that winds may be as high as Force 5 and the clouds low.

Eisenhower and his staff took the news without comment. They agreed to reconvene and discuss things further that evening.

Stagg avoided Yates’ gaze throughout the meeting. Stagg and his deputy had argued strongly on the way over about revealing to the Supreme Commander that the weather centres were divided in opinion. Yates insisted that Ike and the others needed to know. Stagg overruled him, and reluctantly Yates had agreed to comply.

As they left the meeting, Stagg made his excuses and broke away on his own to take a walk through the grounds of Ike’s headquarters. He needed time to think.

“Was it fair to the Supreme Commander to withhold the cleavage of opinion from him?” He later wrote when describing that lonely walk. “Yes. I argued with myself: ‘General Eisenhower has big enough problems of his own… We have no brief to make his task more arduous than it manifestly is.’”

The problem, Stagg realised, was that there wasn’t just a lack of consensus, but that he firmly believed from his own reading of the data that Widewing were wrong. As long as the Admiralty refused to commit to a forecast, or sided with Dunstable, then he could in good conscience convey the majority belief to Eisenhower as if it represented the whole – as long as no one ever asked him that question directly. If the Admiralty’s view shifted, however, then he would be forced to either side with the minority view, or deliver an opinion that he firmly believed would lead to catastrophe.

Besides, just how much of his belief was based on the data, and how much on a subconscious tendency to trust his old colleagues at the Met Office more than the Americans? Stagg worried that he may be doing this without realising it.

And if that wasn’t enough he was worried about Yates. Stagg knew that he was placing his deputy in an increasingly difficult position. Technically Widewing was Yates’ command, and he knew that Yates both trusted their ability and felt duty bound to support them as their commander. Right now Stagg was asking him not only to go against that, but also asking his deputy to trust Stagg’s belief that they must present a consistent world view over Yates’ own belief that this was wrong. It was an enormous ask of the man, one that grew larger by the day.

Pushing these thoughts to one side, Stagg returned to the weather hut. Dunstable had indicated they would be pushing for new data before another conference call that afternoon. Stagg wanted to spend as much time as possible running the numbers and trying to come up with a plan.

20:00 June 2 1944. The Weather Hut. Portsmouth. D-Day -3

The afternoon conference call had not gone to plan. This one was not doing so either.

Stagg had hoped that by getting each weather centre to explain the rationale behind their decision-making it might open the door to a consensus. Instead, the sides remained as far apart as ever.

Things were about to get even worse. As Stagg listened, the Admiralty admitted that they now believed that what Widewing were saying was at least partially correct. The high pressure Widewing were so insistent would protect Normandy may not do so entirely, the Admiralty claimed, but they now forecast it would do enough to mean that only light cloud would cover the area.

Both Dunstable and Stagg were horrified. There were three depressions heading this way, Dunstable insisted, heading over the Atlantic past Ireland. The data suggested that these would develop over Scotland and sweep in wind, cloud and rain that would most likely push south and mask Normandy right at the time the airborne troops were landing and the fleet was at sea.

Stagg’s worst case scenario had happened. He firmly believed that Dunstable were right, but it was now two against one. Widewing and the Admiralty believed the Invasion could go ahead. Dunstable disagreed. Across the table, meanwhile, Yates remained ominously silent.

For an hour and a half the debate raged, but no consensus emerged. In the end both Yates and Stagg had to sprint to make their evening briefing with Eisenhower.

In that meeting, Stagg once again told Ike and his staff that the situation was unchanged. As a noticeably uncomfortable (to Stagg at least) Yates looked on, Stagg insisted that it was still impossible to make a call on the weather for D-Day, but that such signs that existed suggested that conditions were deteriorating, not improving.

After the meeting Stagg went for another walk to clear his head. As he returned to the weather hut afterwards he overheard Yates on the phone to Widewing. Yates was begging Krick and Holzman to ring Dunstable before tomorrow’s conference call and resolve their differences. From his reaction it was clear that the pair were not enamoured with the idea, but after much pleading Yates did manage to secure one vital concession – tomorrow they would agree to accept, and back, Stagg’s decision on whether they should advise Eisenhower to postpone D-Day – even if it conflicted with their own opinion.

That day, as Stagg was heading to his quarters, he bumped into General Morgan.

“Good luck Stagg;” The General told him, aware that tomorrow would be the moment of truth for the meteorologist. “may all your depressions be nice little ones.”

“But remember,” He added, after a slight pause, “we’ll string you up from the nearest lamp post if you don’t read the omens right!”

Stagg did not sleep well that night.

June 3 1944. HMS Hoste. West Coast Of Ireland. D-Day -2

Of all the duties a destroyer could have, Lieutenant Hoare considered weather readings one of the most thankless. Especially, he noted, when taking them required spending a lot of time in an area of sea that Germany’s U-boats seemed to enjoy spending a lot of time in.

At least today, he suspected, U-Boats would not be a problem. Overnight the weather, which had been looking ominous for a while, had finally closed in. As he ordered the latest set of weather readings broadcast back to the Admiralty he wondered absent-mindedly whether they were actually doing anything with these numbers. He hoped so. Otherwise it was a very poor reason for getting a man and his crew so wet.

11:00 June 3 1944. Blacksod Point. Republic of Ireland. D-Day -2

The phone had been ringing for a while by the time Maureen got to it. When she answered she was surprised to hear the voice on the other end of the phone was English. She wanted Maureen to confirm the weather readings that had been sent through in the early hours of that morning.

“I’ll need to get Ted,” she warned the voice, “stay on the line.”

Having located Sweeney she brought him back to the phone where he confirmed both the results and the methods he had used to collect them.

Barely an hour later though, the phone rang again.

“It was the same lady.” Maureen recalled, over 60 years later. “The lady with the English accent and she asked if we could please check and repeat the very latest weather observations we had sent from Blacksod. So Ted repeated those ones again.”

Both Ted and Maureen agreed that whoever this English woman was, she seemed awfully interested in the weather.

20:00 June 3 1944. The Weather Hut. Portsmouth. D-Day -2

The Admiralty representative was the first man on the conference call to speak. Their view, he said, had changed. Although they still did not subscribe to Dunstable’s full forecast, they did believe that cloud and winds over Normandy on the day of the landings was now more likely than not. Dunstable insisted more than ever that their negative forecast was correct, based on the latest data from Blacksod Point.

Widewing continued to insist this was not the case. Yes, as they’d admitted the day before, the high pressure they had counted on to protect the beaches was not developing in the way they’d hoped – but they still firmly forecast that Normandy would remain protected from the weather. The invasion could go ahead.

There would be no consensus forecast. Stagg and Yates finished up the call and headed across the grounds to see Eisenhower.

21:25 June 3 1944. Southwick House. Portsmouth. D-Day -2

As Stagg waited in the hall for the Supreme Commander’s briefing to begin, he suddenly realised that Air Chief Marshal Arthur Tedder, the man responsible for the Air Force during OVERLORD, was approaching.

Tedder, Eisenhower and Montgomery

“What the devil has been going on behind the scenes in recent days, Stagg?” He asked, “Will you please tell me?”

Tedder explained that he had been up at Bushey Park that morning to meet with General Spaatz, commander of all the USAAF in England.

Whilst he had been there Spaatz and himself had decided to call on Widewing, where Krick and Holzman had shown the two airmen their forecasts – forecasts that ran counter to the general image of pessimism that Stagg had been presenting.

“Now tell me Stagg,” Tedder insisted, gently, “just what has been going on around you?”

Stagg’s blood ran cold.

“I’m afraid the weather centers haven’t quite been seeing eye to eye in recent days.” He answered, slowly and carefully. “Widewing’s techniques have led them to be more consistently optimistic than I have thought to be warranted, and I have taken the responsibility of toning down their contributions to the forecasts which I have been bringing you in there. I’m sorry if the Widewing people feel that I have not given their views the consideration they deserve; but I can assure you that nothing would have made me happier than if I could have accepted their forecast of weather for the week-end and Monday.”

Tedder looked at Yates, who was standing next to Stagg. Yates looked at his commander, then at Tedder, and nodded his agreement.

“For everybody’s sake,” Tedder said, looking back at Stagg with his voice level, “let’s hope it will turn out alright.”

21:30 June 3 1944. Senior Commander’s Briefing. Portsmouth. D-Day -2

The weather, Stagg explained to Eisenhower and his commanders, had turned against them. The incoming depressions would cause disturbed conditions in the Channel and assault area throughout the 4th and 5th of June. Winds of up to Force 5 would hit the beaches and surrounding area, and cloud would be low and think with limited visibility. It would rain both here on the British coast and on Normandy.

As he was talking Stagg could not help but frequently glance out the window. Neither could the assembled staff. Outside it was a lovely day.

Throughout the briefing Eisenhower remained quiet, his chin resting on his hands and his eyes firmly fixed on his meteorologist.

As Stagg finished, silence descended.

Leigh-Mallory, broke it. He asked Stagg what the conditions would be for his bombers and fighters. A 2,000ft layer of cloud would obscure the ground, Stagg said, somewhere between 1,000 and 5,000ft. Another layer would exist at about 11,000ft.

Admiral Ramsay, the man tasked with seeing the Navy fulfil its obligations to the invasion asked whether there would be high winds on Monday and Tuesday. Stagg confirmed that this was their forecast.

Eisenhower listened to his staff’s questions and Stagg’s answers, and then turned to Stagg himself.

“Last night you left us, or at least you left me, with a gleam of hope. Isn’t there just a chance that you might be a bit more optimistic again tomorrow?”

“No sir.”

Thanking the weathermen for their input, Eisenhower dismissed them and asked them to leave the room. As they turned to depart, however, Tedder spoke up.

“Before you go, Stagg,” he said, “will you tell us whether all the forecasting centres are agreed on the forecast you have just given us?”

Stagg paused. He remembered the phone call between Yates and Widewing the previous day. Realising just how much he now owed to his deputy, he turned to Tedder and replied.

“Yes sir. They are.”

With that Stagg and Yates left the room. A few minutes later General Bull joined them and told them that inside they were debating a delay.

Stagg nodded wordlessly and stepped outside. As he did so, Tedder approached.

“He turned to me,” recalled Stagg later, “and, smiling, said, ‘Pleasant dreams Stagg.’”

Tedder lit his pipe and walked off. Above them, the sky was almost clear, the air calm and quiet.

04:15 June 4 1944. Senior Commander’s Briefing. Portsmouth. D-Day -1

“The sky outside here at the moment,” Admiral Ramsay said, “is practically clear and there is no wind. When do you expect the cloud and wind of your forecast to appear here?”

Stagg had just finished delivering his first weather briefing to command of the day. He had told them nothing had changed from the night before and this was true in more ways than the staff knew – for the last hour and a half the weather centres had been in discussion and none of their positions had changed. Dunstable and the Admiralty still said bad weather was imminent over the Channel. Widewing said it would remain clear.

The only difference now was that there were signs, Stagg felt, that the front might be moving faster than expected. Another report had come in just minutes ago from HMS Hoste suggesting that the weather front was moving faster than expected. If that was the case then things might clear briefly in the next few days. It was too early to tell though, and Stagg kept that fact to himself.

It was decision time. Eisenhower permitted Stagg and Yates to stay in the room.

“No part of the air support plan would be practicable.” Leigh-Mallory said. Tedder agreed.

Admiral Ramsay reluctantly concurred. If the forecast was correct, the seas would be too rough.

Of Eisenhower’s lieutenants, only Montgomery disagreed. As they spoke, he pointed out, ships and landing craft had already begun to depart. Various plans and deceptions had been laid around this date. To turn back now would risk chaos or – worse – German discover of their intentions. Forget the Air Force and the airborne assault, he insisted, they should go.

“Jesus!” Eisenhower shouted at Montgomery, temporarily losing his calm, “Here you have been telling us for the past three or four months that you must have adequate air cover and that the airborne operations are essential to the assault, and now you say you will do without them!”

The Supreme Commander regained his composure.

“No, we will postpone OVERLORD for twenty four hours.”

The decision was made.

13:00 June 4 1944. Blacksod Point. Republic of Ireland. D-Day -2 [REVISED]

Ted had brought down another set of weather readings and they’d had a good chat again. Maureen was starting to suspect he might be sweet on her. She didn’t mind – although she wasn’t yet ready to admit it, she was a bit sweet on him too.

The future Mrs Sweeney picked up the post-office phone and reported the readings. The barometer had now definitely stopped dropping. It seemed a break in the weather might be coming.

20:30 June 4th 1944. Convoy U-2A. The Channel. D-Day -2 [REVISED]

It had taken two destroyers frantically dispatched from Plymouth to catch Convoy U-2A and persuade it to turn round. The 247 vessels of the convoy had already been at sea when the decision to postpone the invasion had been made, and the signal to return had been missed. They had been halfway to France when they finally got word.

At first the sailors and men of the convoy had been surprised at the order, cursing it. Now though, as night approached and the last stragglers struggled into the shelter of Weymouth Bay through the rain and wind they were far more sanguine about it.

Stagg’s forecast had been right.

21:30 June 4th 1944. Senior Commander’s Briefing. Portsmouth. D-Day -2 [REVISED]

“Gentlemen,” Said Stagg, “since I presented the last forecast some rapid and unexpected developments have occurred.”

As the rain and wind whipped against the French doors of the meeting room Stagg proceeded to explain. The reports coming in from HMS Hoste and Blacksod Point increasingly suggested that the bad weather was moving through the Channel faster than than expected. There was still more to come, but that was following slowly.

The weather now battering the coast would continue through Sunday and into June 5th as expected. June 6th, however, now looked like it might be clear – as would the next day. Indeed if their forecast was right, the conditions would be perfect.

Eisenhower needed a two day window. Stagg suggested this might be it and (though he didn’t mention it) all three of the weather centres for once agreed.

“Admiral Kirk must be told within the next half hour if OVERLORD is to take place on Tuesday.” Ramsay said, referring to the commander of the Naval task forces that would need to set out once more.

Ramsay, however, also offered a warning.

“If he is told it is on and his forces sail and are then recalled, they will not be ready again for Wednesday morning. Therefore a further postponement would be for 48 hours.”

Everyone in the room knew what Ramsay was saying – if they started, and stopped, again, they would lose any chance they had to attack in this window of opportunity. They would have to delay until the middle of June at the earliest.

“Looks to me like we’ve gotten a break that we could hardly hope for.” Said General Beddell-Smith. “It’s a helluva gamble this.”

Eisenhower turned to Monty.

“Do you see any reason for not going on Tuesday?” He asked.

“I would say…” replied Monty, pausing, “…Go.”

Discussion continued briefly, but for everyone the decision seemed to have been made. Stagg had been right about the need to delay. They would trust that he was also right about the sudden chance to proceed.

““Well boys, there it is.” Said Eisenhower. “I don’t see how we can possibly do anything else.”

Ike watched the rain and the wind raging outside – the weather that, had they proceeded, would right now be wrecking his invasion fleet. Finally he turned to his Chief Meteorologist.

“Well, Stagg, we’re putting it on again: for heaven’s sake hold the weather to what you’ve told us and don’t bring any more bad news.”

00:00 June 6th 1944. D-Day

Stagg lay on his bunk. Outside, over the last few hours, the weather had finally cleared.

Right now, he knew, 59 convoys, crewed by almost a quarter of a million seamen, were steaming towards and through the milky-white waters of the Channel. In their holds and on their decks were 130,000 soldiers and 2,000 tanks – all headed towards the same place – Normandy. In six hours or less they would arrive at low tide and the attack on the beaches would begin.

Above his head, he could hear the sound of thousands of bombers, heading out into the dark night to discourge paratroopers on the unexpecting enemy.

The liberation of Europe had begun…

…and the weather was perfect.

For the first time in two weeks Group Captain James Stagg slept like a baby.

The author

Editor of Lapsed Historian, John Bull is a journalist and a historian whose interests cover everything from the Classics through to the history of computing. He has a particular affection for obscure moments in history that have had a big impact, but which are today otherwise forgotten. In addition to writing about history, he also writes about London Transport for London Reconnections and on football for .

3 thoughts on “The Longest Forecast”

  1. Could I ask where you obtained the name of the Hoste’s meteorologist, Lt Hoare, from? I have a completely different name which was provided by the meteorologist on the Hoste’s sister ship.

    1. Lt Hoare is listed as commander of the Hoste by John Ross in his book The Forecast For D-Day, which is well worth a read.

  2. Great story. Very engaging.
    Just one little thing – any chance of changing “Nissan hut” to “Nissen hut”?

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