Summer 2024/25 Seasonal Outlook

Craig Brokensha (Craig)
Swellnet Analysis

The seasonal shifts are well underway and with this our weather eye shifts from south to north: from the Southern Ocean to the tropics.

Cold fronts are losing their sting as the westerly storm track retracts to the south, while the warming waters off the East Coast are beginning to stir.

Last week, the Bureau of Meteorology released their tropical cyclone outlook, forecasting an average year of tropical cyclone activity region-wide (eleven to be exact).

A glimpse of what's to come this summer (Greg Neverka)

However, of the four Australian cyclone regions, only one is a consistent swell producer - the Eastern Region - and even it doesn't extend very far offshore. Its eastern boundary includes Lord Howe Island, but not Norfolk Island, New Caledonia, or at least half of the Coral Sea.

This is important as the best swell-producing cyclones usually form in the distant Coral Sea, or they deepen there. This means they're not accounted for in the BOM's seasonal outlook.

Therefore, if East Coast surfers are to get a better sense of what to expect we've got to look further afield, into the South Pacific basin, specifically the region north of New Zealand, extending west into the Coral Sea.

All things considered, this cyclone region has the greatest influence on East Coast surf, especially when considering the potential for systems to spread swell energy down the New South Wales coast.

Recently, New Zealand’s National Institute of Water and Atmospheric Research (NIWA) put together their tropical cyclone outlook for surrounding waters and it provides a more useful outlook for the swell generating regions in question.

2024/2025 Tropical Cyclone Outlook (NIWA)

The outlook shows the majority of possible cyclone activity forming to the east and north-east of the country which is favourable for swell production across Queensland and northern New South Wales. Compared to long-term averages, the expected activity around New Caledonia and Vanuatu looks to be be normal, with slightly elevated risk around the Solomon Islands, Papua New Guinea, and New Zealand’s North Island.

The outlook revolves around increased sea surface temperatures to Australia’s north-east thanks to a likely La Niña event - albeit a weak one - over the coming months.

Assessing all the regions, those monitored by both Australia and by New Zealand, the outlook for East Coast tropical cyclones still appears average. For surfers that's neither good news nor bad, yet any form of La Niña also increases our odds of swell generation - just not necessarily from tropical cyclones.

La Niña seasons, even weak ones, results in a shift of the subtropical high pressure belt further south than is normal, opening up the East Coast to increased trade-wind and swell activity.

The warmer than normal water building up to the north and east of the country results in increased instability, lower pressure and in turn stronger than normal trade-wind activity when squeezed against the high pressure to the south.

The below image shows the probability of a difference in Mean Sea Level Pressure from the long term average over the months January, February, and March.

Probability of Mean Sea Level Pressure being higher (orange)/lower(blue) than normal for January/February/March 2025 (ECMWF)

Readers can make out the increased trade-swell setup for the East Coast (lower pressure immediately to the east) along with more favourable winds from the north-eastern quadrant for South Australia, Victoria, and Western Australia (but with less swell thanks to chances of higher than normal pressure to the south-west).

This outlook favours the East Coast over the southern states, but with an improved wind outlook for South Australia and Victoria compared to the normal south-east blow. This latter point can also be taken as a positive, especially on coastlines exposed to southerly swell. Also, expect more humid weather (relative to normal) along with this lower pressure across South Australia and Western Australia.

Comments

mowgli Tuesday, 15 Oct 2024 at 12:35 pm

DI here I come

NoUseforaName Tuesday, 15 Oct 2024 at 03:43 pm

Let me know when your going and I’ll text all my mates and get them to text all their mates and we’ll all go together.

Sprout Tuesday, 15 Oct 2024 at 06:16 pm

They were going already, along with all their 2nd and 3rd cousins and long lost international relatives. Everyone else is off to Cylinders.

bbbird Friday, 18 Oct 2024 at 11:41 pm
billie Wednesday, 16 Oct 2024 at 09:10 am

I used to see a fella in Cronulla that often wore a "NoUseForAName" t-shirt. I thought it was nouse as in "mouse". For further crappy stories, refer to my snappychat and other various social media platforms that I post on incessantly.

caml Tuesday, 15 Oct 2024 at 01:53 pm

Thank you for the information Craig

Dx3 Tuesday, 15 Oct 2024 at 02:31 pm

To be honest through Spring and Summer I'm resigned to lower levels of swell in Vicco and am fine with it. For my general well-being and enjoyment, I'll take NE's every single day of the week over the brutality of SE's. A cold shit wind that just makes life depressing in or out of the ocean on the west coast of Vic.

Nick Bone Tuesday, 15 Oct 2024 at 05:53 pm

One mans trash is another mans treasure

dbut Tuesday, 15 Oct 2024 at 05:57 pm

IMG-2889
Yea what gives you the confidence of more NEs and the Bite not being bound for one of these high pressures locking up that’s defined the past couple summers and creating endless SE and upwelling west of Portland.

geek Tuesday, 15 Oct 2024 at 10:04 pm

Makes for good MTB weather but give me a warm NE'ster and 3-4ft any day

Craig Wednesday, 16 Oct 2024 at 07:36 am

The position of the inland low pressure. It's not going to be E/NE-NE all summer but more so than usually seen.

Island Bay Tuesday, 15 Oct 2024 at 05:41 pm

I believe that first chart is first collaboration effort between MetService and NIWA since we got split in two in the 90s. More to come!

And fwiw, NZ gets more cyclones in neutral years.

only-sams Tuesday, 15 Oct 2024 at 09:11 pm

First tropical activity of the season looks like it’s about to hammer east coast NZ later this week. If you ever wanted to do a strike mission that’s the kind of swell you wanna do it on.

Mickieyoyo Wednesday, 16 Oct 2024 at 06:21 pm
Lanky Dean Wednesday, 16 Oct 2024 at 12:52 am

Very informative, thanks Craig.

freeride76 Wednesday, 16 Oct 2024 at 08:24 am

As Craig mentioned, seasonal shift well underway and already strongly into that cool ENSO phase pattern.

Question I keep asking: is this a structural shift?

Is the West Pacific warm pool and EAC strengthening such that this pattern is becoming the defacto new normal, even allowing for cool and warm ENSO phases?

I know I've kept harping on about it but seasonal reversals now seem common. Look at the current pattern: lingering low in Tasman, tropical low forming in trough near Fiji. Warm Bluewater across the sub-tropics, constant strong S-SE surges with only brief N'ly interludes (not extended episodes).
We've already had a strong low forming off the North Coast.
Record rainfall for Lismore for Sep.
Flood plumes out of the Northern Rivers.

This is all typical late summer/autumn stuff, not October.

If this was a structural change the big winners would be eastern seaboard and losers would be Vicco/SA.

Of course, it could be temporary "noise" and not a true signal.

Sprout Wednesday, 16 Oct 2024 at 11:12 am

2015/16 - Last 'good' years here, as in it's not been better since.
2025/26 - Will see a return to good because reasons *cries in blind hope*.

Distracted Wednesday, 16 Oct 2024 at 12:44 pm

@Freeride, I recall thinking in the 19/20 East Coast drought if it was a sign of the future climate and also that I would never complain about too much rain again.

Hasn’t panned out that way since then and if this summer is another La Niña it’s really going to test my non complaining intentions!

Mickieyoyo Wednesday, 16 Oct 2024 at 12:57 pm

Moving to Waihi beach NZ
Looking forward to fun summer swells from the NE

only-sams Wednesday, 16 Oct 2024 at 03:50 pm

Waihi-a-mea Bay as my old man calls it

Some fun waves around there out of the westerlies and with a bit of snooping some thumping beachies.

Buy a little tinny to launch off the beach because the fishing is world class.

Mickieyoyo Wednesday, 16 Oct 2024 at 06:22 pm

Frothing for some matakana action

Island Bay Wednesday, 16 Oct 2024 at 06:40 pm

Good luck, mate. Let us know how you go.

Edit: And during the inevitable flat spells, you can always drive west for two hours. You would have loved today (faaark!).

bbbird Wednesday, 16 Oct 2024 at 09:10 pm

Thanks for the update Craig. The ocean is energised.
The whales are flying down the east coast to Taz atm.
There's plenty of powerful arching airs on display, males leaping for joy. A great show tonight.
https://www.windy.com/-Menu/menu?currents,-31.971,161.719,5
Maybe enjoying a cruise with their mates, before the next deep low slows them down... east of Eden.
An interesting roadtrip story. eg. Ch2. Brothers & rivals

Audiobook 4hrs for the big surf trip
or the musical (only 14minutes)

Herman was an immigration officer on Ellis Island...recalling wild stories, reading & then writing a tall tale looking for the white whale..

bbbird Wednesday, 16 Oct 2024 at 10:58 pm

9hrs audio of the years in the hot pursuit of pleasure.

velocityjohnno Thursday, 17 Oct 2024 at 09:50 am

Great booklist there!

Bring on the NE summers and warm sunny fun swells, with huge amounts of daylight to surf from 5 till 9

Tooold2bakook Thursday, 17 Oct 2024 at 11:59 am

Good news for MP!

Oink Friday, 18 Oct 2024 at 08:01 pm

What's the latest on La Nina?

Craig Tuesday, 22 Oct 2024 at 01:27 pm

The Pacific is still showing a nice cool signal across the central regions and the Niño 3.4 region is hovering around -1°C with a strong trade-wind burst underway (blue/purple shading) which will cool things further.

https://i.imgur.com/BrF9BW5.png

https://i.imgur.com/RPML9ht.png

https://i.imgur.com/27TfTWL.png

Oink Wednesday, 23 Oct 2024 at 11:56 am

cheers Craig,
so does that mean it's going to be pissing down all summer along the east coast or sunny or a bit of both?

Craig Wednesday, 23 Oct 2024 at 03:31 pm

Depends where you are situated. The wetter signal looks to be central NSW based rather than northern or far south..

Dec/Jan/Feb
https://i.imgur.com/2uENOoJ.png

Also here's the relative Niño against the warmer than normal global signal, shows a stronger Niña than current observations tell..

freeride76 Friday, 18 Oct 2024 at 08:28 pm

From BOM climate driver update: The chance of a La Niña event developing in the coming months has decreased compared to recent outlooks. If a La Niña were to develop, it is forecast to be relatively weak (in terms of the strength of the SST anomaly) and short-lived, with all models forecasting neutral values in February.

Solitude Friday, 18 Oct 2024 at 09:39 pm

Yeah right. I thought last update had it being a near foregone conclusion.

bbbird Friday, 18 Oct 2024 at 11:16 pm

I wonder if whales sing songlines, folklore fables & wild stories of close encounters

bbbird Friday, 18 Oct 2024 at 11:29 pm
Spuddups Saturday, 19 Oct 2024 at 06:06 pm

Anyone know how common is it for cyclones to make landfall in Northern NSW, SE Queensland?

southernraw Sunday, 20 Oct 2024 at 09:45 am

Sunday morning around the grounds on the cams with a cuppa, and it appears the whole country has miserable surf this morning. 2ft semi clean Dbah was the best i could find.

freeride76 Sunday, 20 Oct 2024 at 10:25 am

I had a fun little splash in some b-grade but unattended waves.
1 or 2 turns and a close-out reo.

thermalben Sunday, 20 Oct 2024 at 10:48 am

Terrible 'round here. Poorly formed windswell, couldn't find any pockets. Scored a clean half hour window of SW winds as a cell moved across the region, then it went onshore. Blergh.

MrBungle Wednesday, 6 Nov 2024 at 10:54 am

Hopefully we get some good winds at least in the mornings in NSW.

Clam Tuesday, 26 Nov 2024 at 06:33 pm

Hi Craig and co, checking in here to follow up from Craig’s predictions last month and a half back, down in SA eyre pen those nor’easters Craig spoke about have been for real , at least 3/4 days lately have been north east winds , and a few moments with norwesters, big swell as well! surprisingly not much blowvember , more so some nice winds surfable all morn at times, without howling sea breeze by 10 am ! As of late there’s been a lot of moisture and some rains , quite a few 5mil rains which is better than average around this desert climate zone ! I’m wondering if the iod has gone negative? I’ve been told today the SAM is negative , there’s been clouds and moisture from the north and nor west quadrants last few weeks, seems to be typical La Niña weather reminiscent of 2/3 years ago , can we get an update on the weather situation / climate drivers please ? The rains are good, sadly it has ruined some fruit that was just ripening , but it will benefit other fruit at a later stage I’m hopeful , got me some apricot and fig just days before the rain! Some nor east winds forecast so maybe it’s going into December getting some small surfable windows, thanks in advance swellnetter team

Craig Tuesday, 3 Dec 2024 at 10:04 am

Cheers Clam, I'll try and have one Thursday once the updated seasonal outlooks become available.

The current moisture is thanks to those warm SST's off north-west Western Australia. This is feeding north-west cloud bands that drift south-east across the country.

https://i.imgur.com/OkDBn7I.png

ron Tuesday, 3 Dec 2024 at 10:38 am

Swell in Vic is rarely the issue, Gimme NE all summer! Surely vic as a whole there's more fun options with a smallish swell running and NE winds than any other combo.

Not sure if it's just my memory but my wife is sick of hearing about how summers didn't always blow SE for 2 out of 3 months and that Northerlies for a week straight with temps going from 25-40 progressively to a change day back to SW for a few days was the standard cycle.

Late 90's i damn near lived in the dunes around the peninsula checking set ups and surfing 3 times a day. A handful of my best surfs ever were down there in that period, usually Feb after holiday crowds had gone home and the All day N-NE seemed to be the norm.