La Niña Murmurs From The East
As the clouds gather and we reach for the umbrella, dare we ask ‘that’ question again?
Are we looking at yet another visit from La Niña?
After the East Coast dried out through June and July, the wet signal has returned, along with plentiful amounts of easterly swell. This at a time when we usually see steep southerly swells glancing the coast on their way to Fiji.
Last summer saw a short-lived Niña signal develop throughout the Pacific, though its stunted longevity meant it failed to reach the requisite threshold for the Bureau of Meteorology while just scraping in for NOAA, the American meteorological service.
The surf and weather through autumn played out as you’d expect post La Niña with multiple flooding events and oversized easterly swell impacting the East Coast from March through May, feeding off warmer than normal sea surface temperatures in the Coral and Tasman Seas.
Since then the Pacific has returned to a neutral state while at the same time warmer than normal sea surface temperatures have continued to hug Australian coastlines, with far spread consequences including the South Australian algal blooms and coral bleaching off the Ningaloo coast.
Sydney is also coming in much warmer than normal with SSTs around 21°C, which is 2-3°C above normal for this time of year - see image below left.
A warm tongue of the East Australian Current is bringing warm, blue water to southern locales (Photo Brokensha)
Shifting our eyes back to the equatorial Pacific, and since July we’ve seen a couple of stronger than normal easterly trade-wind bursts, cooling sea surface temperatures slightly in the form of upwelling. This upwelling has promoted the development of a sub-surface cold pool which may feed any further, favourable upwelling winds.
Crucially, the wind forecast for the coming month shows just that, with a significant burst of stronger than normal easterly trade-winds due over the coming fortnight, followed by possible further activity into September.
If this comes off as forecast, we’d see the cool water signal in the Pacific Ocean deepen further while piling up warm water in the western Pacific, pushing us towards the La Niña thresholds.
However, it’s not just about the sea surface temperature, with a fully fledged Niña requiring the atmosphere to become coupled. If air rising in the west, above the warm pool, begins feeding back to the east this would complete the feedback loop, driving even stronger easterly winds flowing westward towards the rising air in the west.
The last few summers have shown that the intensity of the La Niña signal isn't always reflected in the effects. If there's enough warm water offshore then even a reduced La Niña can bring rain, floods, and lots of easterly swell.
Above, a typical La Niña lineup: grey, wet, and windy (Neverka).
Since the start of the 2020’s we’ve largely been in La Niña. One of the drivers that explains this persistent La Niña pattern is the Pacific Decadal Oscillation (PDO).
You can think of the PDO as a long-lived El Niño or La Niña-like setup throughout the Pacific Ocean, which has both warm and cool phases. It takes into account the sea surface temperature anomalies (difference from long term average) across the wider Pacific basin, with a horseshoe of warm water wrapping the cooler signal across the central and eastern Pacific Ocean.
A quick look at the basin wide sea surface temperature anomalies shows this pattern clearly, with the PDO index currently showing a reading of negative four, the coolest reading on the reconstructed record dating back to 1854.
With such a low reading, the current setup also increases the chance of a developing La Niña.
The Pacific Decadal Oscillation (PDO) over the past thirty years, showing a record negative dip into July (NOAA)
Lastly, the Indian Ocean Dipole - another regional climate driver - is also hinting at a coming La Niña.
Currently, the difference in water temperature across the Indian Ocean basin - cool off eastern Africa and warmer off Indonesia - makes it a quasi-negative Indian Ocean Dipole (IOD) setup.
A negative IOD and La Niña typically complement each other, which makes it one last point of persuasion. It also makes the weather outlook lean towards wet and the swell more easterly.
We’ll provide updates on any cooling or increased chance of La Niña in the commentary below and future articles.
Comments
So WSL final is going to be crappy
Outlook isn’t great.
I was in Fiji all July and we had one 3 day run mid month of waves and the rest was under head high. Cloudy under head high is very average. And SE trades were very strong so even when there has been waves the surface conditions have been average. In the two weeks since returning there’s been nothing and outlook for next 2 weeks looks dire as well.
The unseasonal easterly trades enjoyed by East Coast are not good for Fiji.
god just has to do fart and there will be waves in the pacific ocean. but sn telling us looking not likely that lines stacked to the horizon.
We'll take the 2022 and 2024 La Nina summers over here, thank you.
You can take every year since 2020, farrrk.
Go away, I’m so sick of all this rain. I’m seriously thinking of moving elsewhere.
Come join us for some algae loving
Id rather the rain than the our lovely algae bloom any day.
No more perfect off shore easterly swells my local just hates them.
Nothing works bring back the south swells and my local lights up.
The rain go away not to mention the now resident white pointer
he has become a unwanted blow in.
Craig -- Jeffreys Bay bodyboarder here. Your weather/surf forecast is top notch. Grateful to learn from you.
What does this mean for the wider Indian Ocean and South Africa in particular? You mention an IOD at the end of your piece. Can you say a bit more on that? We were having an all-time June/first part of July and the day after the JBay Final, it feels like the swell just stopped/switched. Been off and on (mostly off) since then.
Thanks CK, will get back to you when I get a second.
NOAA have just switched to La Niña watch..
https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory...
This image below shows the current relative, sea surface temperature anomalies across the world, and below that the incoming easterly trade-wind burst which might kicks things over.
And where did the "the incoming easterly trade-wind burst which might kicks things over." come from?
And BOM, in their infinite wisdom, are not doing the ENSO Outlook anymore. Have they got rocks in their heads?
Doesn't make any sense at all. They just need to get their messaging in order.
Noooooo! No more rain!
Thanks Craig
Another La Nina wont be welcomed on the Surf Coast by too many people. The autumns and winters have been below average down here since 2020/ 21 when we got 3 in a row. This winter has been below average again as far as I'm concerned. Just don't seem to get many good runs of W and NW winds and swell. Last September was a good one though.
La Niña is on the whole good for waves in NZ. Apart from when we get wacked by Cyclones. West Coast is clean and offshore. East Coast gets plenty of East Swell. The southern tips of both Island get less of the wind that can plague those locations. In 2022 I did a two week boat trip to Fiordland and it only rained once.
I'm sure everyone's opinion will reflect how their local fares during LN conditions, so I'm the same Spud.
On the whole, this coast works better when the swells swing more east and the banks are also better when flash floods blast the beaches and nearshore zone. So I'm feeling for other people but quietly happy about what's to come. Call if conflicted.
All that said, there will be local casualties. Already a string of houses above a popular wave are threatened, steadily losing land each swell or rain event (they're built on clay above coal seams so when the clay gets waterlogged it gives way at the cliff).
A day after last week's east swell I noticed a concrete seawall built to protect one of the houses had given way and already the land behind is subsiding. Built in a different age, I doubt they'd get permission to rebuild the seawall as it's on top of a rock platform.
I think Spuddups might be indulging the rose tinted glasses a little; also being a resident in his city. Like the Victoria region we were fully skunked for good Sth angled swells and we were subjected to weeks of cold miserable Sth East systems through what were meant to be our summers. Perhaps he doesn't remember so well because he was away for decent portions of these un-summers scoring waves elsewhere.
Haha, so no I don't really share his positive outlook on the La Ninãs, although they're all a bit different so who knows.
You're right about our fair city Yendor, generally pretty crappy in La Niña, other than the relative lack of wind. I was talking about NZ in General.
Wow Stu, that is nuts. In similar vein to the Thommo's question - who was McCauley?
Samuel McAuley. From the WCC website:
"From the Parish map for the area, it appears that the first land grant in Thirroul was made to Samuel McAuley (later referred to as McCauley) on 1 June 1855. Other original land grantees were Joseph Roberts, James Holt, Jane Rose, Thomas Rose and David Ballantyne (Map of the Parish of Southend, County of Cumberland, 1921)."
There's also an occasional back-and-forth on the Thirroul Living FB page about people calling the whole beach McCauleys, when it was first known as South Thirroul Beach (AKA Southy), and only the reef at the end of Corbett Ave was named McCauleys.
Over time that shifted so the whole beach is now called McCauley's - that's even the offical name on land maps - and only the southern end gets called Southy.
Thanks for that.
On the back and forth.. McAuley's for us was always the reef/sand at the base of the cliff. However I've heard some younger crew use it to refer to the beachie, as you say.
Brings back great memories of being the youngest who got thrown in the back of a hilux sucking exhaust as a young fella.
In a material sense, the formal classification is irrelevant now.
The wet signal is here and it's profound.
It's rained every day this August, the ground is fully saturated and we're ringed by huge cumulus towers with monsoonal rain plumes everywhere.
I've had this conversation with colleagues before. Often the wet signal precedes the formal classification, it's the tendency towards one state or another that matters.
La Nina's can go either way here. 2020 was almost the perfect year, and 2021 was very close to it as well.
2022 was disastrous flooding.
2024 had moments before the bank got washed out.
2025 has been a mess.
It does completely transform the seasonal expectations though. Autumn can be a soggy mess.
Spring can now be almost completely devoid of NE wind episodes and have the best surf of the year.
The current outlook is almost frightening - EC now progging some disastrous looking black nor-easter set-up with a deep infeed into a coastal trough.
Almost frightening you say?
Not to quote myself but to quote myself:
"Buckle up. This event is going to create some "interesting" outcomes.
The current rain event is impressive and behind it and on it's heals will be something for sure. Exactly what I couldn't tell you he wheels are in motion and the anomalous outcome merely a formality. "
https://www.swellnet.com/comment/1096989#comment-1096989
So those El Niño years when there is hardly an east swell and just south swells is the sand at the point usually a lot better… or just hit and miss
Such annual variability over here too.
2022 had very bad floods in the W/NW of the South Island, with loss of life. Rained twice in 6 months here in Raglan, and it pumped.
2023 very wet here.
2024 the best summer of swell I've ever seen, with 5 or 6 proper 10ft swells in Jan-Feb.
We've just had two weeks of bone dry air, bright winter sunshine, and decent swell. Been building steps in the garden, and digging through the clay pan was easy and not soggy. Not your normal winter.
Despite the algae the Middleton to Goolwa stretch has had great waves from April to July. Best in years, given the shitstorm we endured since COVID. I should say that stretch is currently algae free, but Waits side its back with a vengeance. And the mid coast is rife with it.
Thanks so much for the oceanography tutorial !! , It is great to learn more about the wild ocean and our planet while planning the next days surf or fishing trip .
This weather is getting to me. Ridiculous number of rainy days.
Very depressing week or more ahead.
the La Niña will continue until morale improves
9 out of the last 12 months have had above mean rainfall for this area.
Most months well above.
This has been particularly pronounced through traditional dry times of late winter/spring.
This year so far at Ballina airport -
1648mm
129/232 days have had rain, so 55% of days.
June/July/August have seen over half a metre of rain - so much for traditionally dry winters in this part of the world.
Yep, and my gauge here, less than 5nm from Ballina airport has recorded way, way more rainfall.
I think that AWS gauge runs very conservative. Not sure why.
Same thing happens here though the reason is clear. Local AWS is at Bellambi which is about 5kms from the escarpment, which causes orographic lifting and increased rainfall for the suburbs under the 'scarp, but not so Bellambi.
Same goes downslope winds. Thirroul can have fully laden wheelie bins taking flight as katabatic winds reach their gravitational peak, but they slow the further from the scarp they travel so Bellambi can be half the strength.
Something about proximity to elevation at Lennox compared to flood plain at Ballina airport, or measuring setup at the airport (or yours), or just the luck of the draw?
Not sure, East Ballina seems to also run high compared to Airport.
Anyway, fricking wet, any way you measure it.
Keep your head above the red muck there, solid totals coming up.
4WD only in the yard here- had to tow my parents out the other day when they parked in the front yard.
The Pacific has already started cooling and things have only just kicked off.
Vicco cops it from the northern states for its weather. Whatever system we’ve been in since last Spring, it’s been the most settled, pleasant weather I can remember. Summer felt like it went for 5 months…. Would take this any year, if we could add a bit more consistency in for the surf coast of course!
I need to find an escape.
Does it rain in South Oz during La Nina's?
No, but the toxic algae takes a bit of getting used to.
which would be preferred re less algae (i realise its a broad brush to paint with)
Not a La Niña. I'd say more so El Niño to stir things up with strong south-east winds and upwelling.
It's just brooding and dark out at sea, everything is soddened, south side walls of the house getting a green tinge to them. Used to surf most days of the week, now it's down to a few days a month. Banks are shite, brown water runoff everywhere, so depressing, even the dog is over it. On the flipside, guitar chops are improving.
Jeezus that sounds grim.
How are the concreters and brick layers and renderers and anyone else who needs dry days to work going?
A lot of people must be hitting the pub early.
Confirming La Niña indications from western pacific latitude 10 north. Unseasonal rain and crap surf
Two typhoons in the forecast period...
...both sending swell to higher latitudes unfortunately.
Heading towards our first 100mm+ day of the year. Ground is already sodden. Creeks running hard and blowing out the entrances.
Pano shot of the north end of McCauleys showing waterlogged clay cliff face slowly giving way.
Wow, not far off those dwellings.
The house you can see on the left also owns the block of 'land' seaward of it. Last year, in a stunning display of chutzpah, they put that block of 'land' up for sale.
No takers unsurprisingly.
Crazy that council has that as a house block. I wonder how much land was seaward of that block, and also #2 with the seawall to the south, when it was all surveyed. Like Collaroy etc. should have been park land > road > houses.
''Should have been...''
Taking a generous view, when it was first zoned you couldn't even call it a short-sighted move, as, for one, beaches and the coast just weren't valued the way they are now. Prior to stainless steel, living on the coast meant everything rusted and few people cared for the aesthetics of the beach.
Around here, the beaches, McCauleys in particular, were dumping grounds. Why build a park overlooking a dumping ground?
Secondly, coastal processes simply weren't understood. It was assumed the coast was a static place.
It's harder to extend that magnanimity towards people who have moved into those houses in more recent times, when coastal processes are understood and observed.
RE dumping grounds. Here's a brick path I'm currently building out of weathered bricks, all of them found on either McCauleys or Thirroul Beaches. Since I took this photo I've collected probably half as many again. All dumped on the beaches years ago.
Interesting, benefit of hindsight, thanks stu. That path looks fantastic!
How cool is that path! You going to link it up to the shed?
Sweep some beach sand into it when you’re done.
Yeah, gonna link to the shed. Need to build decking off the shed first. In that photo I was just laying them out for visuals and to get a count on how many I needed.
When I lay them I'll probably dig a shallow trench, lay a light coat of mortar to help level and stabilise, then sweep sand into the gaps. Gonna put up a new fence, then re-turf the yard this spring, maybe put something different in that island.
Awesome Stu.
110 mm in my gauge from 9am yesterday.
Bucketing down last night in torrential monsoonal downpours under slow moving t-storm cells.
Flash flooding down the end of my street.
A few proper heavy, windless, torrential, summer style tropical downpours here recently too.
sheeeeesh! out of curiosity, is there a BOM-esque site that tells you how much rainfall fell in any given region over any given time? all i see is estimates
Not sure Alex.
If I were living in Lismore or any other flood plain town I'd be feeling very, very stressed right now.
Torrential here.
Again.
Over it!
About 150mm for the 24hrs to 9am here and has smashed the previous 24hr record for August. Still torrential now.
It’s like autumn hasn’t finished.
Where are you?
Mid North Coast
130mm at Kingscliff in the 10 hours since 9am.
Gonna be a soggy field for the final U/11 footy match this weekend.
160mm here now from the start of this event and well over 300mm for Aug.
Aug mean rainfall is 75.8 (second driest month after Sep).
The wettest month statistically is March with 260mm.
So the second driest month has smashed mean rainfall for the wettest month.
If this is La Niña just murmuring, god help us when it's full blown and roaring.
maybe this is only the beginning ........
Implications for indo in the coming months and over summer with a return to La Nina?
This most recent summer saw consistent Indo swells.
Sea surface temperatures have dived across the central Pacific Ocean following the recent burst of easterly trades, with a possible stronger event inbound (bottom image)..
Forecast 850hPa zonal wind anomalies
What would this in combination with a negative IOD mean for the east coast Craig?
Wetter than average through the coming spring with less embedded NE wind events.
The IOD has just gone strong negative..
Thanks for the info
Is there any reason why October seems to be extreme (+ or -)?
That's then the signal properly kicks in. It's usually a spring climate driver and then weakens through summer.
Spring rainfall forecasts shown on ABC news last night by Tom. Most of southern Qld, nearly all NSW and Vic expecting above to well above average rainfall.
The only saving grace was that the most was west of the ranges, as you would expect for rain generated from a negative IOD. Sydney Newcastle Wollongong were looking much closer to average.
Just no more atmospheric rivers from the east, please. We have had enough. Can’t think how many times I looked at the radar so see a ball of rain from Newcastle down to almost Ulladulla, just day after day.
Is there a more clear picture of the MECHANISTIC nature of La Ninia?
I'll wait.
Absolutely force feeding through Centro Am. and across the pacific to the Coral Sea...
The 90 day especially very clearly shows the "spinning up of the equatorial zone and large deviation from norm. This has been occurring (being done) for a long time now.
"Just a little trade wind bump", "SST's are the single cause" - yeah, nah.
Very nice. Also I've never said that SST,s are the main driver for these developing La Niña's. It's a consequence of greater atmospheric drivers that then self feeds onwards from there.
ok, thanks for clarifying and agreed. I thought you were tending to say SST's lead or enhance the atmospheric drivers versus interplaying off them or self feeding as you describe it.
Of most note is that the atmospherics in the Atlantic seem to continually be organizing into outcomes that result in huge outflows NE to SW that feed across and enhance the Bermuda high.
This recent blow example (outflow off the enhanced Bermuda high) literally tore the sand from the Sahara in August:
This is being reflected in the Hovmollers consistently.
Cool charts. Where did you get them?
They're available here:
https://mikeventrice.weebly.com/maps.html
Let's do a thought experiment...
That's what you do when you need to delicately suggest stuff a lot of people potentially can't handle the suggestion of.
I think.
Let's continue anyway.
Thought experiment - Could you "construct" or at a minimum enhance La Niña?
Does #1, feed #2, feed #3 here? And does that flow onward (eastward) to result in a strong #4, #5 cycle and "loop" ultimately repeating?
Charts and plots are nice, but satellite's seem to show best what's actually going in the central US and the Atlantic:
This similar (and consistent) setup shows clearly again from August 3rd:
The Bermuda high unified wind field sometimes stretches from Ireland to the Caribbean and that is 7500-8000km's or more - massive. ALL that air has to go somewhere and actually drives atmospheric outcomes and upwelling in the Pacific / Southern hemi.
Another recent date (September 9) matching again to the same general setup...
Sometimes these setups just seem to be visually representative of idealized computer modelling outcomes being realized rather than organic natural patterns.
Over and again, a unified and strong wind field in the Atlantic "spins up" the equatorial zone.... and the mechanics of La Niña play out.
In this thought experiment we won't allude to the how's or what's might be "powering" or making possible #1 - lest we breach one too many controversial topics.
Mature, open minds can hopefully see the possible connection/feasibility here.
Second last line: we won't allude to causes and reason.
Last line: You allude to them.
The last line is actually referring to the entire post and premise of mechanistic enhancement of La Niña.
That's all the feedback you have?
Thought there would be punters defending their precious little paracosm and that the suggestion is absurd.
The second last line I don't get into the specifics of atmospheric manipulation. But once you've observed the tom fuckery as I have here in Toronto (ground zero) and understand that the upper atmosphere controls the lower, it all makes sense and the satellite imagery just completes the picture and confirms it.