How it Unfolded: Forecasting for One of the Biggest European Storms in History

Jason Lock

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Updated 827d ago

This is it. Pull out your guns or your biggest excuses, because Europe is officially on. That juggernaut of a swell has arrived in the UK and Ireland and is due to peak in Portugal, Spain and France this evening and into tomorrow morning. Colossal conditions are forecast for the likes of Nazare, Mundaka, Hossegor – and we'll be bringing you all the action live from our webcams as this thing throws down in full brute force.

There's a few caveats here though; we know Spain has just shut its borders with some French surfers in the vicinity having their cars vandalised overnight to stop them paddling out, France is considering another lockdown tomorrow, Ireland is already closed. If you've travelled to score a wave in this swell and it pays off, kudos to your determination.

Live cam: Nazare
Live cam: Mundaka
Live cam: Supertubos

Ain't this a thing of beauty?

But as we've seen, surfers are poised at Nazare, for perhaps what will be the headline of this swell event – remember, this isn't just another swell, this is one for the North Atlantic record books.

This is our final forecast update before we switch to live converge of the swell filling in via our cams on Facebook and we'll drip feed content via Instagram and all our social media platforms – and we'll drop wrap up pieces from Friday.

Remember, this was just the damn warm up on Monday!

For the last time this swell, MSW forecaster Tony Butt breaks it down: “The swell is now imminent, and can’t be stopped. An early pulse of very long period swell – from Hurricane Epsilon before it merged with that other system – has already arrived at westerly extremes, and will soon be swamped by a much bigger swell everywhere.

“Wave heights are already hitting 20 feet on the west coast of Ireland, with periods of up to 20 secs and strong winds from a westerly quarter. In Galicia, the swell is due to ramp up within the next few hours, exceeding 20 feet with periods of 18 to 20 secs and fresh southwest winds.

“Tomorrow sees wave heights and periods gradually decreasing, with winds backing around to the south. The swell quickly fills in along the north coast of Spain, reaching the Basque Country and Southwest France later today, peaking overnight and continuing through tomorrow.

“Wave heights at exposed reefs will exceed 15 feet with clean conditions in mostly light variable winds. At the same time, the swell fills in down the west coast of Iberia, hitting the Nazaré area later this afternoon, peaking overnight and continuing through tomorrow. Nazaré itself will probably hit 30 feet, with moderate northerlies at first but then light variable winds later. Other exposed spots will be around 15 feet or so, with good conditions if you know where to go.”

Earlier, October 26: We could well be on for a record breaking swell come Wednesday and Thursday in Europe this week.

The critical event we mentioned earlier – where Hurricane Epsilon merges with a mid-latitude depression as it travels past Cape Farewell, hasn’t quite happened yet, but most of the models agree that it is imminent, and should occur within the next 36 hours. Once that actually happens, we’ll be able to say with a lot more confidence that there will be a very big, very long period swell this week. Perhaps even comparable with some epic swells in the past, like Hercules.

Latest forecast chart, HERE

Chart for 1pm Sunday. See Epsilon just off Newfoundland, with that other low lurking off the west coast of Greenland? The two systems are expected to join forces very soon to produce the big swell expected this week.

Chart for 1pm Sunday. See Epsilon just off Newfoundland, with that other low lurking off the west coast of Greenland? The two systems are expected to join forces very soon to produce the big swell expected this week.

As of 09:00 UTC Sunday, Epsilon is located just south of Newfoundland, speeding towards the northeast at about 30 mph. It is still a hurricane and is just about to transform from a tropical to post-tropical system as it travels out of the warm water of the Gulf Stream into colder waters further north. It will still contain hurricane-force winds for some time, and is expected to expand in area massively.

The chart also shows another low that emerged off the northeast coast of Canada and is currently just to the west of Cape Farewell. Tomorrow, Monday, this system and Epsilon are expected to merge into one giant low. Once this happens, the system is expected to continue to strengthen and expand as it moves eastward. The other crucial thing is the existence of a large, stable area of high pressure west of the Azores, pushing up underneath Epsilon as it deepens. This will create a strong pressure gradient on the southern flank of Epsilon and a broad area of storm-force westerly winds stretching practically all the way across the Atlantic, which is what will generate the swell.

The 48-hour swell forecast already shows a large area of open-ocean wave heights of 40 feet or so to the west of Ireland. Once that happens, there will be no stopping the swell arriving at west- and northwest-facing spots all up and down the west coast of Europe and beyond. Local wind conditions for when the swell arrives are still a bit difficult to know, but we think there will be quite a few spots with good conditions. Here is what the latest local area forecasts are saying.

In northern and mid areas, the swell arrives late Tuesday, pumps all day Wednesday and tapers off gradually over the next few days. Wave heights at, say, Mullaghmore will probably hit 20 feet with periods of 18 to 20 secs and fresh to strong southwest winds.

In mid areas such as southwest Ireland, Cornwall and northwest France, wind conditions are not so good, with strong to gale-force westerlies for most of the time. Wave heights at exposed spots in southwest Ireland will be well over 20 feet, with periods of 18 to 20 secs.

Further south, conditions are potentially much better, as that high pushes in from the west at the same time as the swell arrives. In the Basque Country, both on the French and Spanish sides, there could be some really good quality big surf, starting on Tuesday, with wave heights still around ten feet from a previous swell, and light southerly winds.

Look at the chart for Hossegor on Thursday, still a way out yet but we'll keep you posted.

Look at the chart for Hossegor on Thursday, still a way out yet but we'll keep you posted.

The new swell arrives during Wednesday, with periods initially over 20 secs and wave heights quickly jumping up to 20 feet or so, and light variable winds. It peaks sometime between late Wednesday and early Thursday, before gradually tapering off. Winds are forecast to remain light and variable throughout.

In northwest Spain, particularly at exposed spots in Galicia, wave heights could hit 30 feet at some spots, with periods exceeding 20 secs. Winds are hard to predict here, but the latest forecasts are showing anything between moderate south-westerlies and fresh westerlies.

Down into Portugal, the swell arrives slightly later, ramping up through Wednesday, exceeding 15 feet at exposed spots late Wednesday and early Thursday, before gradually decreasing over the following days. Wind conditions are expected to be good, with light variable winds or light easterlies throughout. Nazaré will, of course, be humungous, with periods around 18 to 20 secs and wave heights that could exceed 30 feet.

As always, we'll be keeping you updated with the latest in this running article. Stay tuned.

Earlier October 23: Things are really starting to look interesting on the North Atlantic charts. As of midday today [Friday], there is a double-centred low positioned between Cape Farewell and Ireland, with a large area of gale-force winds on its southern flank.

This is already generating swell and is expected to continue doing so for at least the next 24 hours, so the large pulse of swell previously forecast to reach west- and northwest-facing spots over the weekend, is now imminent. Westerly exposures in Ireland will receive the biggest wave heights, but also the most ragged conditions, with strong winds from a westerly quarter. The cleanest surf will probably be found in the Basque Country and at one or two north-facing spots along the Spanish coast. The swell hits most places some time on Saturday, continues through Sunday and then tapers off later on Monday.

This is from Monday morning, you can see Epsilon on the left, pushing further into the North Atlantic, while another disturbance delivers swell for Europe on the right.

This is from Monday morning, you can see Epsilon on the left, pushing further into the North Atlantic, while another disturbance delivers swell for Europe on the right.

Meanwhile, Hurricane Epsilon has just passed Bermuda and is forecast to turn towards the northeast tomorrow, before accelerating out into the open North Atlantic. On Sunday, an innocuous-looking area of low pressure moves out off the northeast coast of Canada into the Labrador Sea, just as Epsilon passes to the south, with a huge trough developing across the two systems at all levels in the atmosphere. If this does actually happen – and I really need to stress that, at this stage, it is still a BIG IF – it could be the crucial event that triggers Epsilon to explode into a massive mid-latitude depression over the following 24 hours. Some models are suggesting a Hercules-like storm, with a large area of open-ocean wave heights of over 50 feet on Tuesday, and humungous, super long-period swells hitting exposed spots. But we still don’t know what will happen for sure.

We'll continue to keep you posted.

Update October 21: Swell on the way this weekend. Before this black blob pulse hits later in the month though (scroll down for that forecast), we've got an earlier XL session set for this weekend in Europe. MSW forecaster Tony Butt breaks it down again: "The upper airstream in the North Atlantic is already starting to look really healthy, with a classic north-south pressure split and a strong, straight jetstream between approximately northeast Canada and Ireland," he says.

Is it time?!

"On the surface, the charts are currently showing a disturbance just off Newfoundland, which will move quickly northeast and deepen, expected just south of Iceland by tomorrow, Thursday. It then expands into a powerful multi-centred system as another disturbance moves in on its southern periphery. A broad area of storm-force winds will generate large pulses of swell for west- and northwest-facing spots, from Saturday through to Monday.

"In the northwest, expect some large, average-quality surf accompanied by strong west or southwest winds. At Mullaghmore, for example, wave heights pick up on Saturday afternoon and continue overnight, hitting 15 feet or so by Sunday morning, with fresh to strong southwest winds. A second pulse of swell hits late Sunday and into Monday, keeping wave heights over ten feet, with winds veering around to the west."

Live cam: Nazare

What about mid areas? "Places like England, Wales and northwest France, wave heights start to increase late Saturday, exceeding six feet at exposed spots for most of Sunday," says Tony. "They then further increase overnight Sunday as a more solid pulse of swell arrives, peaking early Monday before tapering off. Conditions are generally average to poor with strong southwest winds, veering west.

"Some of the best quality surf will probably be found in the southeast corner of Biscay, at spots such as Mundaka. The swell arrives overnight Saturday and continues to increase throughout Sunday, around six to eight feet with light to moderate west or southwest winds. On Monday, the swell becomes more solid as that second pulse arrives, hitting ten feet but with slightly lumpy conditions in moderate gusting fresh westerly winds.

Our Nazare chart for Sunday and Monday.

Our Nazare chart for Sunday and Monday.

"Further south down into Portugal, the swell arrives on Sunday morning, quickly ramping up to ten feet or so at exposed spots, with poor wind conditions in fresh north-westerlies. The second pulse of swell arrives on Monday, with longer periods and better conditions, with light to moderate north or north-westerlies. Wave heights are well over ten feet at exposed spots. At Nazaré, the long period and northwest direction will probably produce some spectacular A-frames over 20 feet, particularly on Monday.

"Then of course, there is Hurricane Epsilon. Currently located about 500 miles southeast of Bermuda, Epsilon is moving steadily towards the northwest with maximum sustained winds of about 75 mph. It is expected to pass to the east of Bermuda late Thursday and early Friday, causing some coastal flooding and hazardous conditions there, before turning right on Saturday and accelerating off towards the northeast. It is still too early to say what will happen when Epsilon reaches the periphery of the other system (the ‘mother system’), but if it gets sucked in like some long-term forecasts are suggesting, we could still get a really interesting pulse of swell around the middle of next week."

And we'll keep you posted over the following days about how this one is going to throw down. Keep an eye on your local forecasts too.

Earlier, October 20: It's been some time since we've seen the North Atlantic look like this. There's a gigantic black blob of swell that's teeing up to rifle straight into Europe towards the tail end of the month, which could make for some seriously impressive surf.

To say we're excited is an understatement. But as with all things when forecasting a potential ex-hurricane swell, there's myriad factors that will go into determining how this plays out. And given how far out this is on the charts (starting October 26, through 29), it's best to keep an eye on our North Atlantic chart or upgrade to MSW Pro so you can check the long-range forecast.

Related content: Remembering Hercules: The Gigantic North Atlantic Storm That Rocked Europe

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Could this be Hercules 2020? This is our North Atlantic swell chart from October 26 through to the 29th - it is a long way out yet but for the sake of getting this at least on your radar - it's worth flagging up. Tropical storm Epsilon is currently forecast to become a hurricane when it approaches Bermuda later this week. After its current trajectory of running up the US east coast, it's looking as if it will downgrade and tear across the North Atlantic before being sucked into another system heading towards Europe, delivering some chunky conditions for everywhere in its path. As with all hurricanes, its track is difficult to predict this early on, but keep an eye on our North Atlantic swell chart as this one plays out - and your local forecast - we'll keep you updated throughout. Expect an early analysis soon.

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You'll remember Hercules back in 2014? A huge storm that engulfed the UK and Ireland, setting records in its path, which this latest disturbance has some parallels with. But before we got too far ahead of ourselves, how likely are we to see Hercules 2020? We checked in with MSW forecaster Tony Butt to get the breakdown: “The upper airstream, which is a major influence for the weather systems on the surface, is easier to forecast than the surface weather systems themselves, because it changes more slowly and has less things to complicate it, like friction.

“At the moment, the upper airstream suggests that things are going to change in the North Atlantic by the weekend. A strong north-south pressure gradient means that there is a good chance that low pressures will form on the surface, generating some type of swell for southwest-, west- or northwest-facing spots. Basically, that’s all we can say.

However, there's the caveat of tropical storm Epsilon. “This is currently positioned southeast of Bermuda, moving slowly northwest and expected to strengthen into a hurricane by early Thursday,” says Tony. “It is then forecast to turn right as it skims past Bermuda on Friday, before accelerating towards the northeast over the weekend, still a hurricane or major storm.

When Hercules roared in 2014, this was the outcome in Belharra, France.

“Yesterday, if you looked at the long-term swell forecast for about ten days ahead, for around the middle of next week, (so unreliable that you could almost call it a fantasy), you might have seen what looked like another Hercules. A massive area of 50-foot seas, driven by hurricane-force winds, in the middle of the North Atlantic. This was because the models predicted that Epsilon would get sucked into a large ‘mother system’ centred just south of Iceland, combining forces and merging into a giant super-low.”

And the likelihood of that happening? “For that to happen, the two systems would need to coincide in time and space, in just the right way so that the energy of both systems combines. Otherwise, they will miss each other like ships in the night.

The current MSW pressure chart for October 27. To learn more about low and high pressure, and how it impacts the surf, go HERE

The current MSW pressure chart for October 27. To learn more about low and high pressure, and how it impacts the surf, go HERE

“It depends on a lot of factors; for example, the trajectory and strength of Epsilon, which in turn depends on the vertical wind shear and the sea surface temperature; the size, shape and strength of the mother system, and the development of other peripheral systems that swing around its southern flank.

“The latest charts are no longer showing another Hercules. But they are definitely showing some good swell for late in the weekend and early next week. We can say that wave heights will be small to humungous, and winds will be onshore or offshore. More updates as things become clearer in the next few days.”