La Niña's Final Chance
Will she? Won't she?
It’s taken until the final month of the year, but it looks like the little girl - La Niña - will finally arrive.
After many false dawns, times when it seemed certain we'd have La Niña develop only to have the numbers retreat, the process is finally starting to take shape across the equatorial Pacific Ocean.
While sea surface temperature anomalies - which is the difference from the long-term average - across the Pacific are yet to dip below La Niña thresholds, the atmosphere is already acting very Niña like.
A quick look at the sea surface temperature anomaly charts reveals a classic La Niña set up: a cool water anomaly is spreading its tentacles west across the Pacific Ocean, while Australia is surrounded by warmer than normal water on nearly all flanks.
Sea surface temperature anomaly as of 8th December (NOAA)
All winter and spring the atmosphere and ocean never really got into synch - hence the false dawns - but now we’ve got a fully coupled feedback system in place. What we mean by this, is that the atmosphere is now responding to the difference in sea surface temperatures across the Pacific basin.
Since mid-November, stronger than normal easterly trade-winds have upwelled cooler than normal water across the equator while at the same time, piled up warmer water across the western Pacific Ocean.
The atmosphere has responded with rising air and lower than normal pressure developing north of Australia (above the warmer than normal seas), then flowing back to the east and falling across the Pacific Ocean.
The difference in pressure between the west and east promotes even stronger easterly trade-winds feeding towards the rising air in the west, inducing more upwelling and setting in motion positive feedback loop. This is known as a coupled ocean/atmosphere and can be confirmed by looking at the Southern Oscillation Index (the difference in pressure between Darwin and Tahiti).
When in La Niña, the pressure over Darwin is less than that of Tahiti in the Pacific Ocean, producing a positive value, and after slowly trending this way over the last month, we’re now clearly above the Niña threshold (+7) with the latest reading coming in at +14.6.
A classic La Niña summer scene with heavy lines under heavy skies (Shield)
Current forecasts have stronger than normal trades persisting all December, further enhancing the ocean/atmosphere coupling and pushing us towards a La Niña event - though it'll be short-lived thanks to its late formation.
Whether or not we reach the technical Niña threshold, the coming summer and autumn will play out like La Niña thanks to the coupled ocean/atmosphere and those warm pools of water surrounding the country.
Below is the next three months Mean Sea Level Pressure anomaly outlook. Of note is the lower than normal pressure expected across the Tasman and Corals Seas, through central Southern Australia and off Western Austalia.
Forecast of Mean Sea Level Pressure anomaly for January/February/March 2025 (ECMWF)
Those in South Australia and Victoria would have noticed the increased humidity thanks to the tropical air mass off our north-west being dragged down across the continent.
In the months ahead (January/February/March), this warm water signal will result in persistent, lower than normal pressure across the Australian region and a subsequent shift of the sub-tropical high pressure belt further south.
This will expose the East Coast to more easterly trade-swell energy while also favouring Tasmania's East Coast due to their exposure to east and north-east swells. That coast usually falls in the doldrums between the Roaring Forties and being too far south to benefit from east and north-east swells, yet a La Niña brings much better swell prospects to the region.
For the southern states, the lower pressure across the continent makes for more favourable local winds out of the eastern quadrant (north-eastern for South Australia) compared to the usual south-east onslaught, but with smaller, more southerly aligned swells thanks to the refraction of the westerly storm track further to the south.
Western Australia is looking at more heatwave conditions compared to normal across the coastal regions thanks to lower than normal pressure setting up west of the state, drawing in desert heat. This will come in the form of strong morning offshore winds, but at the same time the swell potential will also be reduced.
This general trend looks to persist into autumn before slowly breaking down into winter as any proxy La Niña signature through the Pacific starts to dissipate.
Comments
Great article, I'm beginning to understand the setup now so a dry west coast and wet east coast. I can't remember what happened last La Nina in Indo. Does it fire? - because of closer proximity swell sources through the indian ocean? Do those pacific easterly trades carry across to indo during our summer?
For Indonesia, we see more mid-latitude systems which brings mid-period swells with a bit more south in them. Not classic years.
https://m.
&pp=ygUQcmFjZXkgc29tZSBnaXJscw%3D%3DThanks Craig, Great update & fingers crossed down on the MP.
Booo hisss. Thanks Craig?
So another fucked summer for Victoria surf wise.
Fuck
Xox
3/4 of Victoria’s main surf zones absolutely love these conditions.
5th one likes your wallet and etag. no matter what the condition
Cheers Craig
How does La Niña/El Nino impact the Philippines in terms of weather/surf?
So good for East of Melbourne beach breaks predominantly facing the SW/W, but dismal for West of Melbourne reefs facing SE/E ?
Negative Sam’s at moment? Might help the southern states
Currently yes, but that will change into the New Year.
Fantastic write up Craig! Do you think this may be a modoki event given the tongue of cold water is stretching out further into the west pacific?
The temps off the EC are pretty concerning too and given how saturated the catchments are in SEQLD/NENSW, I think we could be in for some trouble if the elements come together!
Hey Murderinc, you make a solid observation. Heading into a major flood cycle 2025-2029. 100 years of BOM records are just puddles (some bigger ones at times but still puddles. Go back 300 years to the 1700s if you want true representation on the matter. Aboriginal records support this. And most certainly when the dams and catchments are full. Shit is going to get real unfortunately. Batten down the hatches and move to higher ground if you haven’t already
Yep out back of Maroochy on the flat where the shopping centre is built I think, mum said that floods big time every 50 years. She thought so much being built on the flats in that locality was really silly.
1956 was the last big one, but only a puddle in comparison to what’s happened prior. The floods took 9 months to travel down from QLD. I’ve played on a tennis court in Alphington that in 1956 was 11m under water. My sister house is on Merri creek in Northcote. Bloody beautiful home. She bought at the low of interest rates and/or before my knowledge of the ‘56 floods. This can bury someone’s life for a long period, so I’m personally invested. Mother Nature is king. Knowledge is power. I do not want this trouble for my sister
It’s interesting what Maroochydores golf clubs plans are too.. look into it. It’s idiotic
Hey Ruckus, you sound like another Inigo Jones observer. Very interesting times?
100% mate and I have keep my eyes on his extended rain dates - he rarely misses from a month or 2 out and its helped run our company with less down time avoiding or mitigating expected rain events given our industry. Its impressive. Worth observation / consideration alone to protect yourself and to position yourself correctly.
It will be very interesting in how these next few years pan out - one would hope for the best but why not considered preparing for the worst.. that way you can protect family and/or friends alongside assets and your wellbeing. Not unfounded to consider
IJ aside I have read some very interesting articles on rising sea levels (in what we would call recent times).
Take the rock platform with the wave cut notch around Boiling Point Noosa as an example - look into it, Very interesting also
Ruckus, you're preaching to the converted! If only it could gain mainstream awareness? Cheers.
Would be very nice, by experience and observation his track record is very very good.
Its a little hard to wrap your head around to a degree (lots of reading ahead) but I am a strong believer in cycles..
We are in a boom (realestate, sharemarket, etc) until middish/late 2026.. (don't quote me on those exact timings) then things go to absolute shit (potentially a stinking pile of it unlike anything we have ever seen before)
If you educate yourself you can ride it out to a large degree, been unprepared will leave you, family & friends in the worst case scenario
Have a good day fine sir
Yeah I had a job up at Coffs and I noticed the old town was built on the high ground (wasn't much of it) whereas the new town is all built on the flood plain. Not hard to work out what happens...our insurance premiums go up.
This is the image that shows the coupled atmosphere with the stronger than normal trades (purple) across the Pacific, while strong west winds (brown) feed in from the Indian Ocean.
The west winds are thanks to an active MJO cycle but it can't penetrate east as it usually does thanks to the proverbial easterly wind wall.
It's set up a standing wave pattern and indicates La Niña like conditions..
That's cool chart. I had to stare at it for a while to figure out what's going on. It's amazing what's on offer these days, even on a big standard site like Windy.
Bring on the waves! God knows we've (east coasters) paid our penance this spring.
You'd expect convergence and vorticity eventually from the W'ly winds hitting the E'ly trade wall.
Personally I don’t want another wet summer, just an average one, la Nina is good after dry years, but this is like the 3rd in the last couple of years. So when La Niña breaks down is it a good chance we’ll go into a El Niño? Haven’t had one since 2018/2019 early 2020 before the big shift to La Niña ….
Last year was El Niño, and quite significant looking at the Niño 3.4 numbers, but lingering warm water around Australia, hanging in from the past Niña's reduced its impact for us.
Copy, hence the small south swells and lack of east swell of winter 2023 on the EC and the build up of sand all along the beaches.. memory had to be jogged. Ha. Good article on that too last year I remember
Yep, this one.. https://www.swellnet.com/news/swellnet-analysis/2023/10/05/sand-in-the-e...
some flashback to get the excitment building
sunday 2nd jan 2022. annual inlaws xmas @grafton. was a solid "4garrys"
https://photos.app.goo.gl/ubXoKDQYfhJqqCj16
https://photos.app.goo.gl/GQxUMoJ1CvSrgpUMA
good stuff. thanks.
Thanks for the climate update. Wondering when the bofins & models could agree.... Its the summer of the cicada.
https://theconversation.com/prime-time-for-cicadas-what-a-once-in-1-547-...
Before the cloud & rain sets in on the east coast, catch some clean waves.
There is a meteor shower show on this weekend; worth seeing just after the moons sets about 5am.
https://www.space.com/34921-geminid-meteor-shower-guide.html
https://www.mooninfo.org/moon-phases/december-2024.html
If you believe in omens, its a sign of your imagination. A horror movie for some....
Epic surf for others
https://www.redbull.com/au-en/episodes/west-oz-cyclone-surf-sessions-s03...
Loved the article on Cicadas and mathematics!
42 years since the album came out- fits the 7 year cycle. Still time to get the band back together-
?si=6xxqS07eoNvcvldhTop track that. Long gone are the days when they'd let riff raff like them anywhere near Five Dock!
Hey Craig
Really appreciate ur articles in this space
Do you ever consider you might have a bais to seeing La Nina events coz ur an east coast based frother and it means better waves for east coasters. If you have considered it - do you do anything to try and adjust for it.
I'm not being a smart arse. You and many others on this forum clearly know a lot more about this knowledge domain than me. But I'm a data scientist in other domains so v curious about forecasters/predictors, how they perceive their own biases, and how they try and adjust for them>
If I'm not mistaken you called an imminent La Nina early this calendar year and I don't believe it ever officically crossed the thresholds and became one? Then I think in Spring this year you called it again? And now I think you're saying, 'it still might happen but officially it hasn't'?
I wonder about this effect about the short-term surf-forecasting also, on swellnet and generally. As it's often (always?) surfers doing the forecast, the forecaster's notes etc.. As surfers they're hoping for good surf so that they have their 'good surf' lenses on when they assess the predictive data. So, they then tend to predict the upcoming surf window with a 'good surf' bias - we see in the data what we are hoping to see, not necessarily what is there kinda thing
cheers mate
NDC, great questions and line of thought.
Regarding bias for La Niña, I think more so other than that it's bias for something to happen, be it La Niña, El Niño or neutral.
Seasonal forecasting is always tricky and I try and not go all in on the outlook, but rather look at the drivers, possible sub-surface warm/cool pools and then watch things slowly play out.
I do enjoy La Niña in regards to the East Coast outlook so maybe there is some bias towards that but I try and keep that aside. As you've noted though I'm more a glass half full kinda guy instead of vice versa, but always keep this in mind and try to not over hype swells etc.
thx craig... the bias for something over nothing - yeah, I should probs be more aware of that one too
I think you'll find if you go back through Signor Brokensha's posts etc., you'll find most (if not all) statements that have a predictive flavour to them are couched in uncertainty and carefully phrased and embedded with get out of jail cards because (1) the data don't lie, but (2) the data don't tell the full story, and (3) the climate is a complicated woman with an ever-present 20% air of mystery/WTF
As a data sci I'm sure you've noticed the cognitive blindspot most people have is they'll read a statement such as "all indicators/data currently pointing pretty strongly to XYZ outcome" and walk away from that reading with the conclusion "it's a sure thing mate!" in their head, and often oblivious they've even done it. Of course, when that outcome doesn't eventuate they'll blame the forecaster for "getting it wrong" or perhaps.....bias. :P
v true mowgli - I knida know Craig approriately qualifies and I dare say I probs did walk away with a simplified and more balck and white conclusion in my head than he may have portrayed in his articles. Seems in pointing out someonelse's possible bias you have cleverly shown me I revealed my own. Too funny. Mostly life's one long lesson in humility I'm finding ... n that aint bad like it might at first seem to be
Cheers
I like the term 'reasoned potentiality'.
Haha I like this comment mowgli specially point 3 and Signor Brokensha's Bahahaha. Plus great comment thread NDC
craig, forecast for pipe master looking any good? couple stray good ones atm. meant to get any better?
Bah humbug.
Always enjoy learning stuff here.. So here when it rains sand build up is pretty crazy.. the more the rain the better but naturally to a point. So how does that effect things your way?
Todays GFS models have forecast two lows dancing around New Zealand before Christmas... maybe a cyclone swell?
https://www.tropicaltidbits.com/analysis/models/?model=gfs®ion=swpac&...
That's the ticket
Hi Craig - what impact will La Nina have on the Hawaain Islands surf/trade wind wise?
Generally La Niña's see the Jet Stream retracted to the north = not as active large swell season, but as of now, the Aleutian Low is going crazy and the next fortnight is overactive. This looks to be feeding off the warm sea surface temperatures east of Japan though.
Just a note regarding the current Niño 3.4 SST anomaly values using the 30 year baseline period from 1990-2020.
The last few years have seen global ocean SST's pushing significantly higher than this baseline and if we compare the current cool water anomalies in the Niño 3.4 region against the average of the surrounding, warm tropical seas, we get a much stronger difference across the Pacific.
This is known as the Relative Niño 3.4 Index and puts us already in La Niña (in line with what we're seeing in the atmosphere).
The science is constantly evolving, but for future outlooks this Relative Index might become more useful as it more clearly depicts where increased/decreased convection, lower/higher pressure would occur.
Traditional:
Relative:
Traditional:
Relative:
NOAA have also done a great article here: https://www.climate.gov/news-features/blogs/enso/december-2024-enso-upda...
For that FN perspective, was re-reading this amazing compendium of First Peoples climate knowledge from D'Harawal Elder Aunty Fran Bodkin and her network. The appearance of the Aurora Australis (the October 2024 Aurora was visible on D'Harawal country) signals the start of the 11-12 year climate cycle and a hot-dry season called Djuli which lasts for up to 20 moons (so has some variability in duration, as you'd expect). The close of the last season in the cycle (called Garuk) is marked by a boom in cicadas. Garuk is a warmer and drier period of 12-15 moons. We seem to have an overlap of those markers this year which would normally herald some hotter and drier times ahead. Do we ever get hot-dry La Ninia's, Craig? Or does the ocean temp dominate the other factors.
Do yourself a favour, get the book:
https://botanicalbookshop.com.au/products/dharawal-climate-and-natural-r...
It may be benefitial to observe, follow the cues of nature & some wise folk whom have lived through or studied the changes of the seasons.
eg. https://journals.sagepub.com/doi/abs/10.1177/0959683609104034
Meanwhile, back at the ranch.... its windy; most of the Indian, Antarctic and Pacific swell is in the holy colours of purple and red.
https://www.windy.com/-Menu/menu?waves,-42.488,158.555,3
Thank God Im not a cowboy riding 6m swell@40km/hr,...or using AI translations;.... atm.
More glamorous than windfarms
Update:
The strong episode of easterly trade-winds has cooled the equatorial Pacific Ocean further and it's now below NOAA's threshold of -0.5°C and sitting just on the BOM's -0.8°C.
We've got another easterly trade-burst to come as well over the coming week.
Nino 3.4 index.. I've also got the past three La Niña years on the chart as well to compare (light grey lines).
Nice updates Craig. For me, decisions around the atmosphere/ocean require consideration of the reliability of the forecast system. ECMWF SEAS5 correlation somewhat good for the increased probability of low pressure from the Jan/Feb/Mar pressure anomaly map posted for east coast area and SA, and very good for the Indian Ocean off west coast - https://charts.ecmwf.int/products/seasonal_system5_anomaly_correlation_m...
Depending on when a decision point is, worth checking in on latest forecast run just ahead of the decision - and quantitatively understanding the forecast system's reliability.
Thanks JCT and great post. It's good to see the decent correlation with the low pressure north of New Zealand in regards to swell potential for the East Coast.
Another update and the Pacific has continue to cool and is clearly in Niña territory for both NOAA and BOM.
The second chart is the Niño 3.4 index and is now at -0.98°C.
Wow, SW Pac is cooking.
Interesting timing of your article Craig, November on the NSW mid north coast had been humid and wet, feeling very La Niña like. Since the article the weather has turned hot and dry with the odd bushfire starting to pop up!
Presumably only temporary and La Niña conditions sound like they will return shortly but I’ve actually enjoyed the hot dry weather for a change.
Yep only temporary and it's been glorious hasn't it. We should see things starting to shift into January.
Hey Signor Brokensha, Lord Mason and Stuart Kettle (always in the cook) Merry Christmas to you all and the Swellnet team. Any chance of a Jan nationwide forecast? I’m sure the paid punters would love it, had a skim across the zones and looks diabolical to a large degree. East coast of Tassie or south coast maybe be the winds not playing ball. Or should we all just move to NZ? Yet to book anywhere but a nation wide / nz overview might be great. Then all the Swellnet punters can go party at the same location. It’ll be one hell of a rambunctious party. Cheers legends. Hope you all had a great Chrissy love to you all x
La Niña has arrived according to NOAA
"La Niña conditions are present and are expected to persist through February-April 2025 (59% chance), with a transition to ENSO-neutral likely during March-May 2025 (60% chance)."
La Niña conditions emerged in December 2024 and were reflected in below-average sea surface temperatures (SSTs) across the central and east-central equatorial Pacific Ocean [Fig. 1]. The latest weekly indices were -0.7°C in Niño-3.4 and -0.6°C in Niño-4, with values close to zero in Niño-1+2 and Niño-3 [Fig. 2]. Subsurface cooling in the equatorial Pacific Ocean strengthened significantly [Fig. 3], with below-average temperatures dominating the central and eastern equatorial Pacific Ocean [Fig. 4]. Low-level wind anomalies were easterly over the western and central Pacific, while upper-level wind anomalies were westerly over the central and eastern Pacific. Convection was suppressed over the Date Line and was enhanced over Indonesia [Fig. 5]. The traditional and equatorial Southern Oscillation indices were positive. Collectively, the coupled ocean-atmosphere system indicated La Niña conditions.
The dynamical models in the IRI plume continue to predict a weak La Niña during the winter seasons, as indicated by the Niño-3.4 index values less than -0.5°C [Fig. 6]. The North American Multi-Model Ensemble (NMME) predicts slightly cooler SST anomalies with La Niña persisting through February-April 2025. The forecast team favors the NMME guidance, predicting weak La Niña conditions through the early spring before transitioning to ENSO-neutral. Weak La Niña conditions are less likely to result in conventional winter/spring impacts, though predictable signals can still influence the forecast guidance (e.g., CPC's seasonal outlooks). In summary, La Niña conditions are present and are expected to persist through February-April 2025 (59% chance), with a transition to ENSO-neutral likely during March-May 2025 (60% chance; [Fig. 7]).
https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml
Also from NOAA..
"Why was La Niña so slow to develop?
The short answer to this is “we don’t yet know.” The emergence of La Niña-like atmospheric conditions before substantial tropical Pacific Ocean surface cooling was unusual, though. The global oceans have been running much, much warmer than average for more than a year, which might have had a hand in La Niña’s delay. When we calculate the Niño-3.4 index but account for the temperature of the tropical oceans (the “Relative Niño-3.4 index”) we get an index that’s been in La Niña territory for months. Only this past year or so has the difference between the traditional and relative Niño-3.4 indexes been so large, and we’re still researching this new measurement and all the implications for ENSO development and impacts in a warmer world."
TLDR: While the current Niño 3.4 values have just reached the thresholds, the relative index taking into account the warmer than normal oceans thanks to climate change, has had us in Niña for months.