Analysis : La Nina watch
While there've been local indicators, such as heavy, persistent rain events, we're now officially on La Nina watch for this coming summer.
The Bureau of Meteorology made the switch earlier this week which puts the chance of La Nina developing over the coming months at 50% (double the the average likelihood). NOAA's Climate Prediction Centre are also on board with 40-50% chance of La Nina forming.
If we take a look at the sea surface temperature indicators across the equatorial Pacific (see image below), a clear cooling has taken place in the eastern and central equatorial Pacific Ocean, while there's been some warming in the western Pacific. This setup usually drives a feedback loop, with strengthening easterly trade-winds across the Pacific Ocean, promoting further upwelling and cooling off the South American coast.
Global Sea Surface Temperature Anomalies (notice cool water across the central and eastern equatorial Pacific Ocean)
Easterly trade-wind anomalies (difference from normal) are slightly stronger and the sub-surface temperature profile is also pointing towards a La Nina event. That being cool water extending deep below the sea surface to the east, with warm water throughout the water column to the west.
Whether this continues and develops into a La Nina event is still uncertain, though as mentioned, most climate models are trending towards either a neutral or La Nina event.
If we do see La Nina developing it will mean an increase in rainfall across central and eastern Australia. The last significant event being 2010/11 when we saw wide-spread flooding across many locations. That was the summer of the Brisbane floods, when the rising waters caused havoc in the Lockyer Valley, 2010 was also the wettest calender year for the Murray-Darling Basin.
With the current forecasts only just reaching La Nina thresholds, a repeat of 2010/11 is unlikely, if it occurs at all.
Here on Swellnet we've frequently discussed the Indian Ocean Dipole (IOD. The difference between this and El Nino/La Nina is that the IOD, which develops during winter, effects rainfall across central and inland Australia through our spring and early-mid summer. While El Nino/La Nina effect rainfall throughout the entire year though focussing on the central and eastern half of the country.
So what does this mean for surf potential?
In 2015 we penned an article looking at the effects on mean significant wave height during El Nino/La Nina. That article used data sourced from a 2011 study by Mark Hemer, “The wind-wave climate of the Pacific Ocean”.
During La Nina years the mean significant wave height increases through the Coral Sea and northern Tasman Sea , largely owing to more frequent easterly trade-swell. However, there's a reduction in swell size for Tasmania and Victoria that's linked to blocking highs setting up across Victorian latitudes.
Change in Mean Significant Wave Height (m) compared to neutral conditions
While having more swell is all well and good, it's the local winds that will make or break a good surf season, and that's yet to be seen.
So sit tight over the coming months as we monitor the developments through the equatorial Pacific Ocean.
Comments
It'll be interesting to see whether this developing La Nina or even tendency towards one alters the trade wind flow back to normal seasonal patterns or whether we get another toxic summer with the dry northerly pattern prevailing.
Oh man, those northerlies were horrible.
I'll second that!!!
With winter so far that's had more summery looking patterns than the norm, I'm not counting my chickens for a good spring this year!!
well spring is spring.
Normally the northerly pattern would start to relax during December- or November in a good year- and we'd get Tradewinds through the summer.
The new normal is the northerly pattern running right through summer.
New normal or stochastic cycles?
good question.
doesn't seem to be a truly stochastic system, but who knows.
The last few years have also seen unseasonal prolonged spurts of noreasters through both autumn and winter. This year has seen more traditional winds through the S and W quadrants with just a few single days of prefrontal N winds. And we've seen a good run of waves. One thing I've noticed during the bad run of the last few years is the belt of high pressure, rather than nice big separated high pressure systems. I reckon we're looking in better shape going into this summer.
yeah, the highs have been in much better shape and located at the correct lats.
This is easily the most consistent year (waves, wind, banks) I can recall for the past 10 or so.
I'll be expecting a few more decent swells or a couple of all day offshores this winter and something good to round out September if we're lucky too. Howling northerlies from Oct through Nov. Hopefully a nice trade pattern returns by early December. Not asking for much (ha!)...….but the way its going it wouldn't be out of the question.
Havent even read it yet, but i know this is going to be a good article, these articles are what makes Swellnet one of the best surfing related sites on the internet.
Ok La Ninas IMHO are better than La Nino's
Good for Vicco beachies and ok for Indo not like La Ninos that cause southerlies for months in Sumatra
El Nino Indo, and the southerlies in Indonesia are linked to the Indian Ocean Dipole and it's positive phase. There are correlations between El Nino and + IOD events but not always.
Any more details and range on the figure above?
Why the significant difference in the Caribbean and the Indian ocean in the figure?
I know they say the correlations are only weak, but I imagine they modeled the globe, not just the Pacific, for comparison.
I assume its NOAA source? Any for IOD and the indian ocean?
Re the Caribbean, during El Nino trade-winds are stronger across that region, hence the increase in size.
The study above is centred around Australia and the Pacific Ocean so don't have more data for the Indian Ocean sorry. Will try and dig deeper for it.
Ok, thanks Craig.
Niña
Niño
Option/alt+N then N on a Mac keyboard. Just saying. It's a small thing but it shits me to tears.
As you were...
Cálmate, surfstarved! There's enough la Niños and el Niñas to go around!
I certainly don't care. But for correctness is would be los niños and las niñas. Plural and gender and all that.
You’ll never find this level of gramma nazi on any other surf related website ever. Another reason I subscribe
Or grammar Nazis.
The heat map in the central / southern pacific is an interesting feature (and the corresponding increased heights in central america)
The lows in that region at the moment look like they are tending towards a stretched out south - north fetch.
I didn't really take any notice at the time but I imagine the june 2006 mexico swell before the search comp was formed out of this pattern. Covid dreaming...
That would be more so linked to the positioning and alignment of the Long Wave Trough rather than the current Sea Surface Temperature developments.
Where I am in Japan, strong La Nina's aren't the best news. The sub tropical ridge tends to extend over the Philippines into the South China Sea, inhibiting typhoon development and pushing the ones that do form too far west to produce decent swell.
Better news if you're a skier though.
Probably not related to this, but the article got me looking at the charts and it seems like all the southern oceans are pretty lined up at the moment. I spose its just the normal winter pattern?
I read that the SAM is heading negative too
That’s should push the southerly storm track further north, and combining with a neutral ENSO or La Niña should bring more snow?
And if these storms are closer does that mean less long period swell and and more dicey winds?
La Nina hasn't formed yet, but yes the SAM is dipping strong negative, though the frontal activity linked to this is being aimed into WA and SA rather than Victoria/NSW. It looks (the SAM) to weaken once the frontal activity moves east over to Victoria, with another strong dip in 1.5/2 weeks time.
So snow wise, while a negative SAM is favourable for bringing the fronts further north and across the country, it's all down to luck on where they are focussed, and right now it's WA.
Spot on Craig!
Keep up your great work...
Cheers Craig...thought you'd be all over it!
I dont think that's enough to get snow on Bluff Knoll!!
I'll keep my fingers crossed for August. Models seem more positive late in the season.
We have had the best Autumn and early winter swell patterns for as long as I can remember. I’ve been surfing for 35 years and can only remember 1-2 years where it had been similar. Consistent swell with reasonable winds on both coasts and more than fair share of waves. Crowds though have never been so bad and that is unfortunately the fault of our lifestyle being sold out to every Tom, Dick and Fukwit. Seems as though Covid has ruined many a thing over the last few months but the ocean has had no worries delivering the goods.
I'll second that Southern. Great conditions by and large all year but circus like crowds. I completely understand why but doesn't make it any easier to like.
Love these articles and commentary. The only thing i really wish is for our surf reporter to stop saying the surf is great when the reality is the conditions are great but surf is crowded straight handers
Covid was a surfest here:)
It’s been fairly epic here in NZ for the last couple of months. Swell from all directions. Good winds.
Interesting . This looked like a lock in the sub surface for a long time . Funny how the professionals at BOM and others inputting data into the seasonal models are so slow to publically recognise the potential of the La Niña .
The subsurface and another milder version of the Nth East Pacific's ( the blob ) of warmer surface waters may temper this La Niña 's strength . ( Atleast thats what the SST feed in signals are telling me) . Buts it's too early to tell what reinforcing effects the resultant Rossby wave of this burgeoning La Niña will deliver .
Another note after we saw a halt to the earlier chances of a strong Negative IOD forming is that the South China Sea already charged which maybe captured from early IOD activity , but maybe early signs of the La Nina's influence on the Indian .
If the ITF does its thing and these Cool upwellings continue to rapidly spread in the NW Indian Ocean then regardless of La Niña's strength , Australia will see effects similar to 2010/11 . As it was the double influence that made that year's ENSO cycle stand out . If you look at the Anomaly SST chart Craig showed at the top of the above article you can see the seed of NW Indian upwelling . And in a few short days its now significantly bigger/ broader .
Shout out to Surfstarved , us PC plebs just wait for people like yourself to do the hard work so we can cut and paste for correct Granma ;-)
The true story here is whether or not this El Viejo is up for what Hughie delivers from all this anti-El Niño .!!
Peace out , this Gringo is going to move to higher ground and crawl back under a rock .
"However, there's a reduction in swell size for Tasmania and Victoria that's linked to blocking highs setting up across Victorian latitudes."
Assume this means the same scenario for SA?
Looking at the charts above, it looks about average, if not a touch bigger regarding west swells through the Bight. Swell direction is hard to gauge there though but seeing the flow on effects from WA, I'm inferring it's west in nature.
Cool thanks Craig. Appreciate the response.
I dunno, but if you look at that map about half way up or more on the right side, there’s some pretty cool looking waves!!
And we're on La Nina ALERT.. No real surprise after the last few months of weather and swells.
"The El Niño–Southern Oscillation (ENSO) is currently neutral. However, continued cooling of the surface of the tropical Pacific Ocean, changes in tropical weather patterns, and climate model outlooks shifting further towards La Niña mean the Bureau's ENSO Outlook has moved to La Niña ALERT.
La Niña ALERT indicates the chance of La Niña forming in 2020 is around 70%—roughly three times the average likelihood."
http://www.bom.gov.au/climate/enso/
Dear swellnet weather Guru Dr Craig,
Last night the Gold Coast had it's first Summer Rains for 2020/21 Xmas season.
With an emphasis on Rain as opposed to Lightning Display.
Seemingly forever now, a Typical Qld El Nino Storm was all Show & No Rain.
We usually wait until Years End for 4 hr Lightning grumblebum Display without rain.
El Nino storms take forever to brew just one drop as rain gauges die of thirst.
Experts flicked the La Nina switch but what local offering do our Rain Godz bring.
As said last night's storm shaped up entirely opposite to El Nino Lightning Shows.
* More orderly Thunder was heard from afar with less subterranean shaking...(Qld)
* No 4hr Star Wars Sabre Rattling...in fact not one Lightning Strike of note. Huh!
* The Storm was upon us fast with bugger all time to clear the washing from the line.
* Gold Coast's La Nina storm showered us fast & efficiently & departed just as quick.
* What Show? There was no show...it just rocked up, did it's thing & pissed off!
* This was no Disco Ball El Nino dry heaving...('Could yer just hold my hair...Ta!')
* Most business like was our La Nina Rain Event.
* Weird part being the Storm self propelled fast with no driving wind...(But How?)
Q: La Nina Storms brew & travel faster, but can it be timed as to EL Nino Fireworks?
Q: Storm Fronts / Wind Gusts / Cyclonic / Rolling > (Wot powers midnite scuds?)
Of course tbb includes the hidden meaning Song Version
(Dancing with you in the...Summer Rain)
This lyrics include Santa Ana winds & Video includes nerdy Weather Radar tech?
Certainly the Song is referencing "Mega Weather Systems" beneath the Radar!
'La Nina rains' are the instrumental driving force in this lifestyle Power Ballad.
Everytime I see the Lightning
Everytime I hear the Thunder
Everytime I close the Window
When this happens in the Summer > (La Nina Summer Rain is Everytime)
Oh, the night is so inviting
I can feel that you are so close
I can feel you when when the wind blows
Blows right thru my heart...
(Song records milestones married to life giving Seasonal Rain)
It naturally & instinctively parallels reliable efficient La Nina migration effect.
It's also drenched in Aussie Summer slip'n'slide pash offs.
1990 As predicted, Summer Rain weathered Oz charts quite a bit longer than o/s.
Oz Mud Army knows what it likes...bring on La Nina...It'll be the death of us!
I sense it's coming TBB. Only 1mm up here overnight, but great to hear it and feel the cooler air. Seems something may be brewing later this week. At least I hope so. My place is waiting patiently, hanging in there, ready to burst into lushness.