Forecasting Hurricane Larry and Why it Was So Special

Magicseaweed

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Updated 8d ago

  • Hurricane Larry is steaming towards Greenland.
  • Long period swell filling in to the UK and Ireland from this evening, September 13.
  • Rare to have western Europe experience proper hurricane surf, without the devil wind.
  • Might not be the biggest but could be a fun event for every surfer.
  • UPDATE: Monday September 13 This is a rare event. You see, this long period swell that will fill in to the UK and Ireland from this evening and into tomorrow and Wednesday, is coming straight from Hurricane Larry and unloading. And it is so special because that first part of the swell comes exclusively from a hurricane that originated way over on the far side of the Atlantic, before it becomes fully post-tropical and merges with another system.

    Usually, when we have a hurricane hurtling towards the UK, it is accompanied with the devil wind. But this time, Larry isn't brining that super strong, onshore wind. The wind is variable, swinging to northerly tomorrow, which isn't great for the likes of the main UK beaches, Fistral et al. And the swell has downgraded somewhat. But after weeks of drought, this swell is a welcome refresher and could be a fun kick off to the start of the season. Word of caution; given that long period, it could mean waiting around a bit between sets, then relatively still water. So take a few more moments to eyeball your local before making a decision on whether to get in or not. Also, if you know of a decent bank, go straight there, as you'll need it to break up the long swell lines filtering through. Better yet if you're near a reef, or pointbreak.

    This explains the unique scenario the UK and Ireland are in for Larry. On the left, our North Atlantic swell chart, which we know you're all used to seeing, but on the right is the swell period - and as you can see, it's coming straight from Larry, with somewhat favourable conditions.

    This explains the unique scenario the UK and Ireland are in for Larry. On the left, our North Atlantic swell chart, which we know you're all used to seeing, but on the right is the swell period - and as you can see, it's coming straight from Larry, with somewhat favourable conditions.

    Anyway, the latest forecast! Hurricane Larry has now been gobbled up by a mid-latitude low pressure system, currently centred just east of Cape Farewell, Greenland. Earlier on, when Larry was tracking east of Nova Scotia, it was still a very powerful system before it became post-tropical. It generated a pulse of super long-period swell, which is arriving at westerly exposures today, Monday.

    Later in the weekend, Larry continued to track towards the northeast and merged with a mid-latitude depression that spawned out of the Labrador Sea, forming a larger system with a broad area of westerly winds on its southern flank. This generated a second pulse of swell that is due to arrive at exposed spots tomorrow, Tuesday, first and biggest in the northwest, then hitting mid and southern areas.

    In Ireland, for example, wave heights ramp up to eight feet or so throughout Tuesday, with periods of around 15 secs, before peaking early Wednesday and then ramping down again. Winds conditions are good throughout.

    In mid areas such as Cornwall, expect a similar pattern, although wave heights are smaller due to the swell shadow of Ireland; up to three or four feet, perhaps slightly larger on Wednesday, with light winds from a northerly quarter.

    Here's Larry, on its tour of Greenland a few hours ago.

    Here's Larry, on its tour of Greenland a few hours ago.

    Further south in Biscay, for example, the swell arrives a bit later, ramping up during Tuesday with very long periods, before filling in on Wednesday and Thursday, with wave heights reaching five or six feet at exposed spots, and light perhaps moderate northerly winds.

    In Portugal, the swell arrives more diminished, peaking on Wednesday and Thursday with offshore wave heights of around three or four feet (bigger at extreme swell-magnets like Nazaré of course), with cleanish conditions in the mornings and fresh northerlies in the afternoons.

    Looking further ahead, another low pressure centre is currently forming just off Newfoundland, which is forecast to track up towards Iceland, generating some strong winds west of Ireland later in the week. This could keep the surf pumping for next weekend and beyond, particularly in areas further south, including Morocco.

    UPDATE: Wednesday September 8: Hurricane Larry is currently located about 500 miles southeast of Bermuda, heading northwest at about 12 mph. It is still a powerful Category-3 hurricane, with maximum sustained winds of around 115 mph. It is also a particularly broad system, with winds of storm force or more extending out to 185 miles from the centre.

    Over the next 48 hours or so, Larry is expected to continue moving northwest, before arcing around to the north as it tracks around that large area of high pressure. In about three days, it is forecast to accelerate towards the northeast and become a post-tropical system as it skirts past eastern Canada and up towards Greenland. Some models are predicting the system to become entrained into the mid-latitude westerlies and continue across the North Atlantic, but this is still very uncertain.

    Larry as of Monday could splurge much more northerly than first anticipated. But the fetch could send lully surf to the UK. It'll be about waiting for the right moments and hitting reefs or points, if this happens.

    Larry as of Monday could splurge much more northerly than first anticipated. But the fetch could send lully surf to the UK. It'll be about waiting for the right moments and hitting reefs or points, if this happens.

    At first, the storm will remain a very powerful system as it passes over very warm sea temperatures (almost 30 degrees C) and as the vertical wind shear remains low. But in about two days it is expected to gradually weaken as it tracks into areas of cooler sea temperatures. Much later, just before it turns into a post-tropical system, it will weaken more quickly as the vertical shear increases and water temperatures become even colder. Despite the weakening, Larry will continue to cover a very broad area, which means it will generate large amounts of swell.

    Around Cape Hatteras, for example, today Wednesday will see some long-period swell of around five feet or so, with light winds. This continues through Thursday and then increases a notch on Friday, perhaps hitting eight feet, with moderate northerly winds off the eastern flank of the system.

    Next week could see two pulses of swell reaching westerly exposures in Europe. The latest forecast for Hurricane Larry is for it to continue a really powerful, broad system as it tracks up past Newfoundland early in the weekend. The hurricane-force winds on its southern flank will spit out a pulse of super long period swell, which will spread out across the North Atlantic and start to hit westerly exposures on Monday. Wave heights will be pretty small and periods incredibly long - well over 20 secs at first. West-facing reefs with extreme focusing will be able to make good use of the long period, otherwise expect long lines and long lulls.

    For the wave starved Brits in the south west of the UK, this will be a welcome sight. The caveat being that long period swell means long waits and straight lines - unless there's a bank, reef or point to break it up. Because it's been flat for so long, it's uncertain how the banks at the most popular beachies are. This is our chart for Fistral.

    For the wave starved Brits in the south west of the UK, this will be a welcome sight. The caveat being that long period swell means long waits and straight lines - unless there's a bank, reef or point to break it up. Because it's been flat for so long, it's uncertain how the banks at the most popular beachies are. This is our chart for Fistral.

    Later in the weekend, when Larry becomes a post-tropical system and moves out into the open North Atlantic, it could join forces with a new centre of low pressure that forms in the Labrador Sea. If this happens, a much broader area of westerly winds will develop south of Iceland, which will generate a more solid pulse of swell for around the middle of the week, particularly for westerly exposures in the north and mid areas. Things are still very uncertain this far ahead and could go either way, so stay tuned for updates.

    UPDATE: Monday September 6: Last week, we peered into the crystal ball about Larry, a system that was moving towards the Caribbean, up to the east coast of the US before boomeranging its way towards the UK and Europe. While that's all still a way out yet (hopefully landing over and after weekend), things are still looking on track this morning, albeit potentially arriving a little later and a little cleaner. One thing's certain though, this EU flat spell is about to break.

    You see, Larry was due to make a beeline straight for the UK, bringing solid surf and strong wind with him. But the current charts show that this hurricane will meet with another system in the Bay of Biscay, and reaching the shores of western Europe with a little less oomph - but potentially cleaner conditions. It is still a long, long way out to really call yet (and we can't stress this enough) yet it is still a hurricane to keep your peepers glued on. We should add that the bulk of the swell will potentially arrive a week today on Monday September 13, but this could all change yet. We will update as the forecast stabilises.

    Here's Larry in the mid-Atlantic a week today. There's another system in the Bay of Biscay...

    Here's Larry in the mid-Atlantic a week today. There's another system in the Bay of Biscay...

    As for the forecast for the Americas? "Hurricane Larry, now weighing in at Category 3 on the Saffir-Simpson Scale, is currently in the open Atlantic about 1,000 miles southeast of Bermuda, moving steadily towards the northwest," said MSW forecaster Tony Butt. "Maximum sustained winds are around 125 mph with higher gusts, and the storm covers a large area, with storm-force winds extending out to 175 miles from the centre.Over the next few days, Larry is forecast to continue moving northwest and then gradually arc around to the northeast and accelerate as it tracks around the southern periphery of a large high pressure system.

    "The intensity forecast is very interesting. On one hand, vertical wind shear is expected to remain low and it continues to track over relatively warm sea surface temperatures, both of which help to maintain its strength. On the other hand, the broad expanse of the system is starting to generate upwelling, bringing cooler water from below up to the surface, which could counteract any strengthening.

    ...and form up to make this. Which could deliver, smaller but much cleaner surf than the models were showing last week. If we're really going to get into some futurology though, even later in the month, another system is due to form and combine with Larry to create some truly epic surf conditions -- but that is pure fantasy right now.

    ...and form up to make this. Which could deliver, smaller but much cleaner surf than the models were showing last week. If we're really going to get into some futurology though, even later in the month, another system is due to form and combine with Larry to create some truly epic surf conditions -- but that is pure fantasy right now.

    "One thing that the models agree on, is that Larry will continue to expand over a large area, which, according to the NHC will make it a “prolific swell and surf producer”.

    Our at-a-glance swell chart for New England. See HERE for more.

    Our at-a-glance swell chart for New England. See HERE for more.

    "A pulse of long-period swell, with periods up to 15 secs or so, is expected to hit East Coast spots as the system moves past from south to north. Around Cape Hatteras, for example, Wednesday and Thursday see wave heights around five feet, with moderate southeast winds. Further north in the New England area, the swell picks up through Wednesday and Thursday with blustery conditions, which could clean up on Friday as wave heights hit six feet or so. Up in Nova Scotia, the swell gradually ramps up through the latter half of the week, with Friday possibly seeing wave heights up to ten feet and light winds."

    We'll keep you posted.

    EARLIER: Wednesday September 1: After what feels like months of flat surf across Europe, we could be about to see some decent surf for the Old Continent – it's a long way out yet, due to hit towards the end of next week, but this this is certainly worth keeping your eye on.

    You see, Tropical Storm Larry is currently spinning towards Cape Verde but could potentially, maybe boomerang away from the Americas and towards Europe, albeit in a weakened state. Larry is due to become a hurricane soon, too, and the results of that means Europe may see incredibly clean waves. If everything comes good. And that's a big if. (EDIT: Larry is now officially a hurricane)

    Live cam: Nazare

    Here's our at-a-glance forecast for Nazare. As you can see, we get an early pulse on Tuesday from a different system, and then, towards the end of the week is when the remains of Larry could fill in.

    Here's our at-a-glance forecast for Nazare. As you can see, we get an early pulse on Tuesday from a different system, and then, towards the end of the week is when the remains of Larry could fill in.

    The swell from Larry is more than a week out, due to hit Monday Sept 13 -- or so the charts show as of this morning. So this really is the realm of fantasy right now. But there's another pulse set for Tuesday as well, which could see sizeable conditions for much of western Europe. We'll keep you updated on that too. (Also, for long range forecasts, upgrade to MSW Pro, you get a 16 day outlook for less than a pint)

    There are no definitives yet but we wanted to get an early warning out there so it's at least on your radar. We're tracking Larry, and accompanying systems, so we'll keep you updated as this thing plays out.

    In the near-future though, Larry could send decent surf to Central America and potentially the US east coast. “Larry, the twelfth named storm in the 2021 Atlantic hurricane season, started off as a tropical wave depression that moved off the coast of West Africa around August 27,” said MSW forecaster Tony Butt.

    “It became a tropical depression on August 31 and a tropical storm at 09:00 UTC, September 1. It is currently about 300 miles southwest of Cape Verde, moving steadily in a westerly direction. Winds at the moment are around 45 mph but strengthening all the time. Over the next 48 hours it is expected to continue moving towards the west and intensifying, becoming a hurricane by late Thursday and possibly a major hurricane by the weekend.

    Towards the bottom left of the image is Tropical Storm Larry, which could become a hurricane at any moment. Now, check the recurve on this beast as it heads towards the EU. Oh it is full fantasy at the moment but can you imagine? Before that though, there's another system in the Bay of Biscay that should deliver swell from Tuesday next week.

    Towards the bottom left of the image is Tropical Storm Larry, which could become a hurricane at any moment. Now, check the recurve on this beast as it heads towards the EU. Oh it is full fantasy at the moment but can you imagine? Before that though, there's another system in the Bay of Biscay that should deliver swell from Tuesday next week.

    “The westward motion will gradually turn towards the northwest as the storm tracks around the southern periphery of a large area of high pressure in the middle of the North Atlantic. Conditions are very good for feeding energy into the system, with high sea temperatures (around 28 degrees) and very little vertical wind shear.”

    But what of the long-term forecast for Europe? Let's crystal ball: “The forecasts are very uncertain, as always with these sorts of systems, but later in the weekend, Larry could still be a very intense storm,” says Tony. “The latest forecasts are showing it accelerating in a north-westerly direction as it tracks past the Caribbean and heads up towards Bermuda.

    “A pulse of swell could hit the Lesser Antilles around Monday, with wave heights of around 5 feet or so at exposed spots. Later again – without getting into the realms of pure fantasy – the system might just double back and re-deepen as a post-tropical depression, helping to generate the first really solid swell of this autumn for European spots. But we’ll keep you updated on that as things become clearer.”

    We sure will.