Late Start To Cyclone Season

Steve Shearer picture
Steve Shearer (freeride76)
Swellnet Analysis

After an off-kilter start to summer where our easterly trade-wind belt took extended smoko then failed to return, and the standard Northern Australian Monsoon (NAM) has registered its latest start in recorded history* we are finally looking at some action across the tropics.

The BOM-issued Tropical Cyclone outlook was for an average season with eleven cyclones, with four in the Coral Sea. Under La Niña (or La Niña-tending) conditions an early start to the monsoon and TC season was predicted, although the link between monsoon onset is stronger for El Niño years.

Monsoon onset and low pressure development - which is the basis for cyclones - is normally linked to active phases of the Madden-Julian Oscillation (MJO) moving west to east from the Indian Ocean into the Pacific Ocean. We currently have a moderate/strong phase of the MJO moving over northern Australia which is expected to both signal the official start of the monsoon and potentially spawn single or multiple cyclones.

The BOM's outlook for this coming Sunday showing five areas of low pressure being watched for cyclone development (Note: cross-hatching indicates areas outside Australia's watch zones)

It hasn't been the first active phase of the MJO this season. A strong phase of the MJO in late November/early December bought on the wet season in Indonesia, spawning twin cyclones from low pressures off Sumatra. TC Fengal headed west to bring death and destruction to Sri Lanka and India, while TC Robyn drifted southwards into the Australian Area of Responsibility to become our first named cyclone of the season before washing out near the Cocos Islands after causing lethal flooding and landslides in Indonesia. Monsoonal westerly winds from that event stalled in the Arafura Sea and failed to impact areas to the north of Australia and Coral Sea.

The late-developing La Niña and associated strong trade-wind surges in the tropical Pacific seem to have repelled all previous MJO phases, almost as if the MJO were hitting an impenetrable wall.

Why the late onset? There are no firm answers, only tentative hypotheses. Chief among them a changing climate which is reducing confidence in the timing and amplitude of seasonal norms. Our surf seasons have been affected by these reductions or reversals in typical weather patterns. Tropical low pressure in October for example, a feature of the last several years. Despite an El Niño pattern last year and predictions of lower cyclone frequency and intensity and later onset we saw Category 5 TC Lola develop in October - the earliest Cat 5 storm ever recorded in the South Pacific.

Seasonal predictions may become of diminishing utility as we move further into a new period of changing climate.

One prediction climate scientists have made has so far held true. Overall number of cyclones in the South Pacific, including the Coral Sea has decreased in line with climate predictions.

This increasing seasonal variability and overall trend of fewer cyclones may spell the end of the mythical Christmas cyclone swell, relegated to the stories told by red-blotched faces around the front bar.

First Point Noosa unwrapping itself during a cyclone swell (Craig Brokensha)

Back to the present. A flurry of activity is expected as the wave of tropical instability caused by the MJO pushes across the top end and into the Coral Sea.

The Joint Typhoon Warning Centre is interested in a low due north of Cairns with a high probability for cyclogenesis in the next 24hrs. If this beats a low in the Gulf of Carpenteria to the punch it would be named TC Taliah. Potential also exists for TC's Vince and Zelia to follow. With the current instability along the trough line, confidence remains very low over specific outcomes so don't get too frothed up or disappointed over single model runs - we will see a lot of to and fro through this week and into the weekend.

Of more importance will be the broad easterly windfield supporting the developing low pressure centres which should at a minimum set up a long-lasting drumbeat of pulsey easterly swells.

Keep tabs on the actual surf potential from this set-up in the Northern NSW and Queensland Forecaster Notes over the following days, and also in the comments below the line.

//STEVE SHEARER

*Over 70 years since records began.

Comments

tail high to the sky's picture
tail high to the sky's picture
tail high to the sky Wednesday, 29 Jan 2025 at 10:45am

Interesting article. I'm wondering abouth the prediction regarding the numbers of cyclones decreasing in the south pacific. Was this a BOM prediction? All I've ever heard was that cyclones were increasing in both frequency AND strength.

thermalben's picture
thermalben's picture
thermalben Wednesday, 29 Jan 2025 at 11:07am

Only climate-change related TC trend prediction I have heard was a decrease in frequency but an increase in strength.

https://www.climatecouncil.org.au/resources/fact-sheet-tropical-cyclones...

freeride76's picture
freeride76's picture
freeride76 Wednesday, 29 Jan 2025 at 11:11am

I first heard it in conversation with Prof Roger Tomlinson of the Griffith Centre for Coastal Management in the early 2000's.

Since then, it seems to have become a widely adopted position.

Mentioned in this piece. https://news.griffith.edu.au/2023/01/19/half-century-of-cyclone-data-put...“Although%20there%20was%20a%20statistically,tracks%20in%20this%20cluster%20are

tail high to the sky's picture
tail high to the sky's picture
tail high to the sky Wednesday, 29 Jan 2025 at 11:57am

Thanks for clarifying guys. I wonder if the same pattern is observed for more local events such as storms. Frequency unchanged but intensity more severe? Probably harder to quantify given how much smaller they are compared to cyclones.

thermalben's picture
thermalben's picture
thermalben Wednesday, 29 Jan 2025 at 2:57pm

That's certainly been inline with my observations. Although there hasn't been any significant trend increase for the number of seasonal storms, local events have higher precipitation totals in shorter time frames, which is causing more damage (drainage can't cope with short term water volumes etc).

Lanky Dean's picture
Lanky Dean's picture
Lanky Dean Wednesday, 29 Jan 2025 at 5:09pm

Growing up on the east coast as a kid. Summer storms and days to weeks of heavy rain in Feb quite common around the old zone.

Nolan's picture
Nolan's picture
Nolan Wednesday, 29 Jan 2025 at 3:50pm

Modelling* commissioned by my employer (an insurer) suggests:
1) Decrease in the frequency of winter East Coast Lows with decrease strongest at higher global emissions scenarios.
2) Increase in rainfall intensity during storms (anywhere from 5-20% increase in intensity per degree of warming).
3) Change in wind intensity, geographic size and pressure level of storm systems is unclear
4) Decrease in cyclone frequency, especially for WA, with decreases mainly in smaller systems
(CAT 1-3). Projected changes in the larger systems (CAT 4-5) unclear. Future decades may bring fewer cyclones overall but when they do hit, they may be stronger in severity
5) There is a potential for cyclones to slow down in forward speed, see their total footprint area of damaging wind speeds grow, and increase in their maximum gust speed
6) Poleward expansion of cyclone systems and increase in rainfall intensity associated with cyclones (as with storm, flood & hail)
* Remembering that projections relating to extreme weather remain uncertain

mowgli's picture
mowgli's picture
mowgli Tuesday, 11 Feb 2025 at 10:21am

I've done some work at an insurer too! Albeit, this one was more a bury-head-in-sand she'll be right we'll figure it out on the day type of exec team. So your employer would likely be one of 3 that have pulled their finger out and commissioned modelling.

I saw some interesting work (out of UNSW i think) indicating an increase in freq and sev of storm cells, and in particular hail storms, over the last 30-40 years. My understanding is the confidence re. storm cells isn't as high as for rainfall, but it's high enough that the general consensus is more of them but they'll be smaller in footprint but more intense and harder to predict. That match up with what you've seen/heard?

dave's picture
dave's picture
dave Wednesday, 29 Jan 2025 at 10:45am

cyclogenesis = is a word I dont hear enough

Craig's picture
Craig's picture
Craig Wednesday, 29 Jan 2025 at 11:13am

The tropical depressions currently in question..

donweather's picture
donweather's picture
donweather Wednesday, 29 Jan 2025 at 12:29pm

I’m thinking most of these tropical lows/TCs progged over the next week or two will get whisked away to the SPCZ. And if no supporting high below then not a huge amount of swell potential from the TCs then. The high itself looks to be the bigger swell producer in terms of swell height and longevity.

Ray Shirlaw's picture
Ray Shirlaw's picture
Ray Shirlaw Wednesday, 29 Jan 2025 at 2:38pm

Can anyone tell me of anywhere on the planet where the Surf quality/quantity has actually improved since the 70s and is likely to keep improving? (Vague suggestions only ofcourse. Promise i wont tell anyone)

Pops's picture
Pops's picture
Pops Wednesday, 29 Jan 2025 at 2:40pm

Homebush, Tullamarine, Abu Dhabi, Lemoore,...

thermalben's picture
thermalben's picture
thermalben Wednesday, 29 Jan 2025 at 2:50pm

This is a difficult question to answer, because you also have to factor in advancements such as technology (surfboards, wetsuits) as well as accessibility (roads, boats, airlines) plus the perennial debate on surf forecasting.

Many of the 'great' waves of the 70's have shifted down the bucket-list scale. Meanwhile, surf spots that were never given a second look at, as recently as the 90's and early 00's, are now part of the weekly social media highlight reel.

Nevertheless, this is a fascinating talking point.

thermalben's picture
thermalben's picture
thermalben Wednesday, 29 Jan 2025 at 2:57pm

Anyway, here's an article Craig wrote fourteen and a half years ago (!) on Skeleton Bay:

https://www.swellnet.com/news/surfpolitik/2012/09/28/skeleton-bay-death-...

Vince Neil's picture
Vince Neil's picture
Vince Neil Wednesday, 29 Jan 2025 at 5:17pm

Totally agree, mutant slabs and tow ins / step offs are all the rage, hence Nates slab tour and JJF taking a year off...

The long walls of Ulus caught surfers imagination in the 70's...a few years ago the focus transferred to canggu, black t-shirt and boardies de rigueur, crew attempting (and mostly failing) airs...

paddling big waves will never go out of style, but that's not everyones cup of tea

freeride76's picture
freeride76's picture
freeride76 Wednesday, 29 Jan 2025 at 3:02pm

NSW over the last 4 years of La Niña dominated patterns.

Vince Neil's picture
Vince Neil's picture
Vince Neil Wednesday, 29 Jan 2025 at 5:09pm

Superbank?

bbbird's picture
bbbird's picture
bbbird Wednesday, 29 Jan 2025 at 7:27pm

Surf quality/quantity is a relative measure. A grom will froth at 2ft.
In North Qld, the trades winds would blow every afternoon and deliver at 3ft mushberger & the locals still surf some bays today.
Big wave chargers seem to want the next big thing... for a dopamine fix.
If I was a teen with P plates or retired, Id say every surf beach in Oz on a hot summer day, is an improvement to school, work, Uni, TAFE, Mc'malls, hot tar burbs, chlorine soaked pools, etc .

GONAD_MAN's picture
GONAD_MAN's picture
GONAD_MAN Thursday, 30 Jan 2025 at 6:35am

Skeleton Bay

BD's picture
BD's picture
BD Wednesday, 29 Jan 2025 at 3:15pm

Sunny coast is bleak lately
Does this lack of swell in prime season indicate that autumn as well will be poor? It deadset feels like we can’t get waves so bad it’s been

bbbird's picture
bbbird's picture
bbbird Wednesday, 29 Jan 2025 at 7:02pm

Deadset, there will be waves up your way next week. Heaps of sealife floating around atm.
SE winds will blow in the bluebottles & other current creatures though. Lycra has its uses.

BD's picture
BD's picture
BD Wednesday, 29 Jan 2025 at 7:13pm

Haha hope so, I’ve lost hope would be stoked to be wrong

bbbird's picture
bbbird's picture
bbbird Wednesday, 29 Jan 2025 at 8:48pm

jimbrown's picture
jimbrown's picture
jimbrown Thursday, 30 Jan 2025 at 2:21am

What's the explanation for decreasing tropical storm frequency? I suspect something to do with wind shear?

Craig's picture
Craig's picture
Craig Thursday, 30 Jan 2025 at 6:23am

Yep, wind shear and a couple of other factors...

"TCs can form only when an initial circulation is protected from environmental wind shear and dry air intrusions, within which prolonged deep convection can moisten the protected region sufficiently to allow a precursor to develop into a TC..

Even in the current climate, much of the tropics are typically hostile to TC formation with the middle troposphere being too dry and wind shear often too strong. In a warming climate, changes in deep convection, wind shear and middle tropospheric humidity are likely to contribute to an even more hostile TC formation environment globally."

With the warming atmosphere, it can hold more moisture which in turn results in a drop in the relative humidity, inhibiting tropical cyclone formation. Interesting eh.

moose68's picture
moose68's picture
moose68 Thursday, 30 Jan 2025 at 3:21pm

Also there has been some evidence that the SWP is experiencing a slowing of the Walker Circulation due to climate change i.e moving to more El Nino like state.
At the same time though, sea surface temperatures are rising exponentially from climate change so more energy available for TCs when they do form. Climate change is accelerating making modelling into the future full of uncertainties for extreme events like TCs. Traditional El Nino/ La Nina patterns may not be reliable.

smokeydogg's picture
smokeydogg's picture
smokeydogg Thursday, 30 Jan 2025 at 10:26am

I appreciate the long term outlook forecasts from swellnet, I mean predicting next weeks swell is tricky enough let alone trying to predict what the next 3 montha may look like.
The win for us WA surfers is la Nina didn't kick into gear and there has been consistent 6 - 10ft swells all summer , imo it has been the best summer for many many years. Hopefully Autumn continues this trend with light winds to top it off, yeeeew !
I think Northern NSW/QLD got enough waves during all those lanina's to share a few with the southern states this summer.

hamishbro's picture
hamishbro's picture
hamishbro Thursday, 30 Jan 2025 at 5:30pm

Quantity not quality/size what most recreational surfers need.
Give us weeks of easterly trade swell varying between 2-4 ft over a massive bank busting cyclone swell.
I’ve got a good feeling this is what February will be like.

tip-top1's picture
tip-top1's picture
tip-top1 Friday, 31 Jan 2025 at 7:03pm

bang on hamish

Solitude's picture
Solitude's picture
Solitude Sunday, 2 Feb 2025 at 4:55am

^^this

Halfscousehalfcockneyfullaussie's picture
Halfscousehalfcockneyfullaussie's picture
Halfscousehalfc... Friday, 31 Jan 2025 at 5:06pm

Hopefully enough easterly spread for the central coast of nsw too….

Andrew71's picture
Andrew71's picture
Andrew71 Saturday, 1 Feb 2025 at 3:10pm

I was just having a read of this article and thought i'd set up an account here so i could make a comment, which is that i'd encourage you all to have a good look at the site geoengineeringwatch.org and in particular watch the doco on there called the dimming. The site and the doco are all about what is happening to our weather. For those that don't watch it for whatever reason, ill give a slight intro. It's about as the name implies geoengineering which is weather manipulation. The american's have been able to do this for decades and can use it for warfare purposes. In one of the doco's ive watched on it ex military people have given testimoney about there involvemnet in it. The dimming might be it, i can't remember exactly. Spraying aerosols in the sky and bombarding the atmosphere at various levels with electromagnetic frequencies(EMF's) are part of the process. For those of you who haven't seen the aerosol trails in the skies as yet, i'm sure you will now that ive mentoined it, just look up more often and you'll see them as well as the seeded cloud that we always get now and the rippled cloud that we sometimes see as well. This is going on right under our noses, and no there not contrails, contrails disappear if they ever appear at all, they don't expand in the sky like the chemical trails do. I'll leave it that, please look at the site and watch the doco the dimming to get clued up on whats actually going regarding our weather.

thermalben's picture
thermalben's picture
thermalben Saturday, 1 Feb 2025 at 3:20pm

Yeah, nah.

udo's picture
udo's picture
udo Saturday, 1 Feb 2025 at 4:05pm

He He.

AndyM's picture
AndyM's picture
AndyM Sunday, 2 Feb 2025 at 2:11pm

Whistleblowers have leaked that chemtrail pilots are chosen from the elite ranks of military pilots, are indifferent to humanity and couldn't care less about killing off unwanted aspects of America and the world.
It's been proven beyond doubt that chemtrails are causing accumulations of aluminium even in the most remote parts of the earth.
Wake up sheeple!

ruckus's picture
ruckus's picture
ruckus Monday, 3 Feb 2025 at 2:07am

Yeah nah

https://www.legislation.vic.gov.au/in-force/acts/rain-making-control-act...

It’s been going on for years on (1967 at least) and/or particularly on the snowy hydro project

The interesting thing is other states can under take weather modification cross border to affect Victoria’s weather and vice versa

Say it ain’t so

Nah yeah

bbbird's picture
bbbird's picture
bbbird Saturday, 1 Feb 2025 at 7:16pm

Most scientists have put their reputation on the line & advised the people and the planets leaders of what is happening now. Many want a quick fix and/or point the finger bone at some badboy bogieman.
Were still burning fuel and throwing out plastic that will be around for 500 yrs in a tip, ocean, etc.

Geoengineering by planting trees for CO2 absorbtion & micro habitat modification is easy pleasy.
References
https://www.forbes.com/sites/arielcohen/2023/09/30/earths-greener-cities...
https://en.wikipedia.org/wiki/World_Scientists%27_Warning_to_Humanity

The "World Scientists' Warning to Humanity" was a document written in 1992 by Henry W. Kendall and signed by about 1,700 leading scientists.

Twenty-five years later, in Nov 2017, 15,364 scientists signed "World Scientists' Warning to Humanity: A Second Notice" written by William J. Ripple and seven co-authors calling for, among other things, human population planning, and drastically diminishing per capita consumption of fossil fuels, meat, and other resources. The second notice has more scientist cosigners and formal supporters than any other journal article ever published.

In November 2019, a group of more than 11,000 scientists from 153 countries named climate change an "emergency" that would lead to "untold human suffering" if no big shifts in action take place:

" We declare clearly and unequivocally that planet Earth is facing a climate emergency. To secure a sustainable future, we must change how we live. [This] entails major transformations in the ways our global society functions and interacts with natural ecosystems."

bbbird's picture
bbbird's picture
bbbird Saturday, 1 Feb 2025 at 7:19pm

If the models cant agree, were in new territory.

dawnperiscope's picture
dawnperiscope's picture
dawnperiscope Saturday, 1 Feb 2025 at 10:05pm

The models seem to have started negotiating and looking to meet half way.
Looks to me like this current low is going to supercharge the coral sea for the next one.

topgeer's picture
topgeer's picture
topgeer Sunday, 2 Feb 2025 at 6:48am

Meanwhile in NZ, the north Island east and west coasts have had the worst surf season over this summer, for at least 6+ years... no swell production out in the Pacific, resulting in flat to 1ft with clean Sw wind offshore.. meanwhile west coast from Raglan north has seen continuous 4-6 ft (and biiger) southern ocean swells, with very few NE offshore winds... even Gisborne has been woeful.

Only places with regular decent waves have been Raglan and Taranaki.

The next few months dont look flash, any EC lows seem to be moving through on SE track at a rate of knots, no fetch and no swell. And they are well out into 5e Pac so none coming down onto north island, therefore no offshore E/Ne winds for west coast.

No one can convince me that we will have a late season.

dawnperiscope's picture
dawnperiscope's picture
dawnperiscope Monday, 3 Feb 2025 at 6:07am

Hopefully it comes good. The next week out in the South Pacific has a bit of potential!

smokeydogg's picture
smokeydogg's picture
smokeydogg Monday, 3 Feb 2025 at 1:42pm

Don't worry bro, the NE winds will settle in late March - May will have plenty of offshore days for the NW coast.
Perfect timing for my 3 week trip home from WA

thermalben's picture
thermalben's picture
thermalben Sunday, 2 Feb 2025 at 9:14am

Unrelated to the surf outlook but holy moly - how are some of the rain totals around Townsville under this current setup.

Paluma has recorded 699mm since 9am yesty, and picked up 182mm the day before - that's just under 900mm in 48 hours... almost a metre of rain in two days.

They also scored 200mm between Mon-Wed this week.

thermalben's picture
thermalben's picture
thermalben Monday, 3 Feb 2025 at 6:40am

Hmm, Saturday's rainfall totals were QC'd (not surprising, I suppose.. may have been an equipment malfunction) but Paluma Dam ended up with 571mm for the 24 hours until 9am (and not 699mm as was showing on the BOM website).

However it's picked up an additional 625mm since then (!) which means they've had 1,196mm in 44 hours.

Add in Friday's 182mm and that's a three-day total of 1,378mm.

That's one point four METRES of rain over the course of a long weekend.

Fark.

Halfscousehalfcockneyfullaussie's picture
Halfscousehalfcockneyfullaussie's picture
Halfscousehalfc... Tuesday, 4 Feb 2025 at 2:20pm

In comparison, Sydney gets roughly 1200 mm a year…. That’s a a lot of rain

dawnperiscope's picture
dawnperiscope's picture
dawnperiscope Sunday, 2 Feb 2025 at 6:42pm

Wow and it looks like a few more days to come.

Spuddups's picture
Spuddups's picture
Spuddups Monday, 3 Feb 2025 at 6:51am

That's a lot of water. Amazing when those floods can make their way across the outback to places miles away from the weather event. You're minding your own business under hot blue skys and suddenly your whole farm is a foot underwater.
A mate of mine works for a mining prospecting company mostly in NT and Nth Queensland. It's the most incredible country up there.

memlasurf's picture
memlasurf's picture
memlasurf Monday, 3 Feb 2025 at 10:58am

Swellnet gold:

'relegated to the stories told by red-blotched faces around the front bar'

bbbird's picture
bbbird's picture
bbbird Monday, 3 Feb 2025 at 8:27pm

Looking at the top BOM graphic & GFS weather models, this could be arrival of the Wandjina; cloud and rain spirits.
https://www.weatherzone.com.au/models/charts/gfs/aus?chartCode=prmsl_thk...
The first Australian weather forecasters?
https://en.wikipedia.org/wiki/Wandjina#/media/File:Wandjina_rock_art.jpg
"Some Dreamtime stories say the Wandjina created the landscape and its inhabitants, and continue to have influence over both. When the spirits found the place they would die, they painted their images on cave walls and entered a nearby waterhole. "The Wandjina can punish those who break the law with floods, lightning and cyclones"
Refererence https://en.wikipedia.org/wiki/Wandjina

bbbird's picture
bbbird's picture
bbbird Tuesday, 4 Feb 2025 at 10:45pm

The first Australian geologists?
Western Australia's Kimberley Ancient Great Barrier Reef (375 million years old)
https://storymaps.arcgis.com/stories/ca4ba29c786b499f8c32d278d83bf1ab

ruckus's picture
ruckus's picture
ruckus Wednesday, 5 Feb 2025 at 7:54am

Crazy that was once a warm, tropical coastline, and home to an extensive barrier reef system. Mind blown great post / link bbbirdman

Look into the wave cut notch / ledge at boiling pot

It’s suggested the platform / wave cut notch could date to the Eemian high stand that was around 120,000 years ago in which the Greenland Ice Sheet melted approximately 25% more than it is now and temperatures were approximately 6 to 8 degrees warmer

We are all but a spec on the timeline