XXL swell for southern Australia
It's not uncommon for the Southern Ocean to throw up large surf deep into spring, but it's less so for one of the most significant storms of the year to develop.
A steady supply of westerly swells provided consistently fun waves across the Victorian Surf Coast through the second half of winter and early spring, but nothing large since the weekend of June 24/25th.
South Australia has fared the same with plenty of decent westerly swells and favourable conditions for the South Coast.
However, moving into this weekend we'll see one of the strongest storms of the year developing south-west of Western Australia, strengthening as it projects east through the Bight as it falls under the influence of a strong node of the Long Wave Trough (LWT).
The LWT is the primary steering mechanism for Southern Ocean frontal systems. Surface fronts follow a path similar, but just a touch west of where the LWT is focussed, and through this weekend we'll see the LWT positioned over the south-east of the country. This will steer and strengthen polar fronts from the Indian Ocean up and through the Bight.
We're currently seeing a couple of weaker systems following this track, but as the LWT reaches its peak over the weekend, we'll see a very intense and large mid-latitude low forming south-west of Western Australia, projecting a sustained fetch of storm-force W/SW winds through the Bight, weakening while passing across Victoria and Tasmania.
This fetch alone would generate very large surf for south-east Australia, but as the system is moving on top of an active sea state created by the weaker fronts before it, we'll see more rapid and larger wave growth than normal.
The low will form late in Western Australia's swell window, limiting the size across Margaret River and further north, but the southern coastline will see XXL surf through Sunday, impacting the West Coast of South Australia with the most size on Monday morning.
We're looking at XXL stormy surf in the 20-30ft range along with strong but easing south-west winds.
Victoria's West Coast will also see XXL surf developing through Monday, but due to the westerly swell direction, the Surf Coast will be 1/3rd the size, building rapidly through the mid-late afternoon to 6ft+ by dark, easing steadily Tuesday. Bigger waves are likely, but we’re being a little conservative right now due to the strong westerly component of the swell. If the low shifts any further north or south of its current trajectory we'll see significant change in the expected surf size.
The West Coast of Tasmania will be hammered by XXL surf, but the positioning of the low will be just a touch too north to generate any major size for the protected South Arm.
A secondary deep low will generate an additional reinforcing long-period SW groundswell for mid-week, but not to the size of Monday's swell. Check the local regions forecast on Friday for a final update on how this swell will translate across your region.
16 day Torquay Forecast Graph
16 day Mornington Peninsula Forecast Graph
16 day South Arm Forecast Graph
16 day Middleton Forecast Graph
16 day Mid Coast Forecast Graph
Comments
Off topic but vaguely related-
Big swells are more likely to deplete or replenish a beach with sand?
Deplete.
They take the inshore sand and deposit it further offshore, making a buffer to the the larger energy. A natural defence mechanism.
Then with smaller swells over time the sand is deposited back inshore.
Big close range swells... Increased energy: more water pushing higher up the shoreface; increased transport away from Inshore; more suspension of fine sand further offshore; rips not necessarily more organised and powerful though.
That's how I see it anyway
The longshore sand movement along my local beach is still being broken up and re-deposited inshore from the June '16 black NE swell. Haven't had a decent outside low tide bank since...only sub 3ft high tide shories...any bigger and it's a car trip somewhere else.
Great timing Hughie. Wrong place, wrong time.
How come Tim?
I am in Nazare where its getting flat then flatter with nothing in sight in the swell window.
Oh bugga
Blowing an absolute sideshore gale here in the SE of SA.
English muffins for breakfast lunch and dinner tmoro
Blowing its tits off here in Vic now. Morning was local magnet about 2ft, clean in N wind, felt like summer... Aireys obs have gusts at 41kts, just had a check swell not arrived as of Sunday arvo. Feels dry like a dry front, but I can see the rain going over Mt Gambier now.
VJohnno..... Nah pissing down here now..... Should be hitting portland as I write this.
http://www.bom.gov.au/products/IDR143.loop.shtml#skip
Cheers Sheepy, nice part of the country you are in. Close to the Coonawarra too! Loved working and travelling through it, would like to try for waves one day.
Watching the radar, I can see the NW flow of rain (Ballarat to Lorne line now) and I can also see a separate SW moving line of rain moving in front of it (Ballan to Leongatha) - never seen a perpendicular moving 'mini front' in front of a front before...
Its a Wild looking system on Earthnull
If you like earthnull, look at windy.com
Just did a 400k+ round trip in one day only to be skunked by sand. Anyone else score on this swell.
any surf from this system?
From where I sit, not much.
Maybe with the increase in whale numbers it's kind of bouncing off them out there at sea, so not really reaching the shore? (actually, have you ever seen hundreds of dolphins out in Bass Straight? That is a sight to see, and quite a bit of biomass too.)
Cape Sorrell saying significant of 5m and max spike of >10m, something is out there...
The Cape du Couedic buoy (off Kangaroo Island) recorded max wave heights of 15.6m (51ft) a few hours ago (significat wave heights of around 9m), with peak swell periods around 17 seconds.
Incredibly, Middleton (Victor Harbor region) is only about 4-6ft right now.. though it is building.
Looking at windy.com west of Aus is this massive like cut off or line where the wind changes direction. Its bigger than the width of Australia. Radar malfaction?
How do you post photos in comments?
https://www.swellnet.com/forums/wax/41251
15 meter wave at Sorrell
Today looks like the day to chase it on my coast. Swell more to the south and light NW winds. Still would be a 250km round trip. But I reckon it'd be on today, no sand to rely on.
8 foot, horrific side onshore on the limestone coast.
Nothing to see here, people........ Move on.
Amazing it's only 8ft feet when both the SA and Tas buoys are recording 50ft max wave heights, with an underlying peak swell period of 17 seconds.
For reference, Peahi was 20ft+ over the weekend, and the responsible was recorded at around 15ft at 19-20 seconds (there are very distinct reasons for this difference - windswell loading being the main one - but it's a classic example of how buoy data ain't the same everywhere).
BTW, not disputing your call SD - been watching the surfcams all day, expecting things to really kick in - but it's certainly taking its sweet time.
Quick splash at lunchtime revealed 3ft sets, a bit overhead on guys at point of takeoff. There were big lulls, then groupings of sets that size. Up to 6 or 7 waves, some only 1 to 2 waves though. Some nice sections presenting. NW to W here, wind has picked up & tide around low.
So it is building, should be interesting on dusk.
Which coast VJ?
Nick that line on Windy, would that be the actual front line? Looks about 1500km south of Cape Naturaliste, wind changes from NW to WSW.
Can it really be that sharp/defined for such a distance?
I guess so - Ben & Craig would be the ones to describe front delineations better. I know they sometimes spawn vorticies at the front, particularly if the air masses are very different, eg fronts going over Halls Head in Mandurah area can form tornadoes, and you see roofs removed on the evening news.
Caveat, we are looking at a virtual recreation of the actual pattern when we view nullschool or windy, so it may not be exactly what the planet is doing. TBH it is far more detailed than any weather chart, internet or TV report I've ever had access to, so I love it!
SC Ben. Edit: magnet spots up to 1ft bigger than this one.
XXL period going up to 18sec !
Perhaps the attention due to bottom friction is making it smaller than buoy stats
Just checked for afternoon, and with high tide and wind certainly in, I was stretching to see 3ft sets, most 2-3ft, almost like it was smaller. Must be the tide eating it.
Must of been super west then. MP was easily 8-10 by mid arvo
Quite often happens on these systems..8m swells when its onshore actually only mean about 2/3rds the height and the rest is wind slop crap. So maybe 5m of swell and 3m of slop..which isnt really that massive.
5m swell "isnt really that massive"?
I dispute that... surf size is relative to a couple of factors, the most important is swell period.
Did you see the WSL comp at Jaws on the weekend? The open ocean swell height was around 4-5m, yet because the swell had a very large period (and because of a couple of other factors), the surf height reached 20ft+ on the sets (40-45ft faces).
You're right in that there was a LOT of windswell contamination at the Cape du Couedic buoy yesterday. But peak swell periods for this event were up in the 18 second range, which shows there was a strong underlying groundswell component. So, there should have been very large waves somewhere (though local winds trashed anywhere exposed).
Your not comparing southern oz to hawaii are you?..not sure what happened but it was nowhere near an 8m swell..or if it was, for some reason it never showed itself.
I think this comes close to Hawaii:
Easliy equal to Hawaii
And as JS once said its the most consistent big wave break in the World.
Yeah that does get close..doubt it was surfed monday though
Absolute bullshit udo .
Jaws is triple the size, every year lately.
Nazare about 10 times bigger every year.
Get a grip
Phhhtt , it doesn't even get close .
If you hadnt noticed there are rarely waves over 10ft in SA .
Just 1 break gets to 15ft plus ,every few years ,As seen on an 8 year old video .
Have you noticed hawaii has multiple breaks, that break at 20ft , 30ft & even 40ft or watever.
SA doesnt get near it , due to the shallow continental shelf in sa.
SA waves/swells lose up to 75% swell power due to bottom friction .
"Attenuation due to bottom friction" .
SA has a huge shelf, except for down south (off the shelf in deep water out at sea offshore )
Those breaks probably haven't been surfed yet .
https://drive.google.com/file/d/0BzwXRXcZyNM3ajBKOHFPU2M1VVU/view?usp=dr...
The Cape du Couedic buoy is 4nm west of the lighthouse. It frequently records swell events comparable (on paper) to those recorded by Hawaiian buoys. So why is it impossible for the KI coast to experience large surf heights such as that seen in Hawaii?
Sure, there are a lot of variables that contribute to to surf size (and as I've said many times before, bathymetry is the main one). I also have a personal interest in researching wave buoy data using different techniques, as I believe there are swell charactericstics that current buoy data doesn't quite pick up on - but I don't think SA is necessarily way off the mark.
It may more so be a case that most of the very big waves that occur in SA simply aren't visually observed because of difficult access and/or poor accompanying conditions.
Some of the biggest waves in oz are certainly at the offshore bommies down south, in SA on the 100m depth straight onto reef .
Nowhere near to the little fantastic noodles wave .
Quote; "In addition, the continental shelf in this
area is very wide, particularly off Streaky Bay in South Australia
(33°S 134°E) where it is about 240 km from the coast to the 200 m
contour and 360 km to the 2000 m contour.
The incident swell will
already be in "transitional water depths" before the 200 m contour."
( From the link study ).
Lotsa difference .
Due south of linguanea island
40 miles out is a XXL reef .
That comes from 100m rapidly onto a dome facing 222 degrees .
One mile of ramp to refract swell onto a 14m bommie .
Thats the one to rival the rest of the worlds big waves
The tide has a massive effect on that buoy too i reckon..really rips through the strait out there...add in the wind slop and its hard to tell how much actual swell was wrapping or getting in
Great paper too (linked) - haven't seen that one before. Thanks.
100% ..you've said it better than i ever could
Didn't say it was an 8m swell.. I pointed out that despite the high percentage of windswell, there was still a large underlying long period groundswell.
And yeah, I am comparing SA to Hawaii. There are a few spots that can certainly produce similar results, though less frequently - we get way more wind affected days down here, and a smaller percentage of large, pure high-end groundswell, due to the way the systems evolve in the Southern Ocean - but it does happen.
No argument from me. My argument is with the fools who dream that the noodles wave rivals hawaii or watever in size .
Waves in hawaii are double the size from the same swell buoy measurement .
Try putting 5-7metres @18s on the noodles wave vs jaws , mavs, todos, cortes , nazare etc .
No contest ,no comparison ,
not even close .
Looks pretty lame on the SurfCoast.
Is that it? Clean 3-5ft surf is the only option?
Kind of feels a bit hoaxy and hyped considering we had 3 clean rideable ground swells in the 6-8ft range in late winter/spring and Craig didn't write one article about them.
For christs sake.
3 six foot swells and you think it's worthy of documentation. Time we both headed west I reckon.
There were huge waves around Lincoln but the quality wasn't there. Surfable though.
That was an island swell. Kangaroo, King and Flinders, but good luck getting to them in those conditions.
wouldn't mind seeing some shots of m l
Photos would make it look like skeleton with the direction but in reality be shitty.
This morning I got sent a few. Not as big as I would've expected but still dreamy.
Got sent there for work. What a setup. I'd be happy if the pics aren't good enough to make WOTD Stu.
Gonna wait a while, if it helps.
It was massive you Kooks .
Quote thermalben ;
"5m swell "isnt really that massive"?
I dispute that... surf size is relative to a couple of factors, the most important is swell period.
Did you see the WSL comp at Jaws on the weekend? The open ocean swell height was around 4-5m, yet because the swell had a very large period (and because of a couple of other factors), the surf height reached 20ft+ on the sets (40-45ft faces).
You're right in that there was a LOT of windswell contamination at the Cape du Couedic buoy yesterday. But peak swell periods for this event were up in the 18 second range, which shows there was a strong underlying groundswell component. So, there should have been very large waves somewhere (though local winds trashed anywhere exposed)."
Yeah that's right ben and i remember debating about this a few years ago on these threads .
Its great to see swellnet team pointing it out lately , i noticed .cheers
You get a surf clam?
It sure had surge and power today, a couple lined up and just shot me through the protected spot I had a paddle at. Like feeling your board being rocketed along. Best feeling in the world.
"The eastern side of the Great Australian Bight is thus ideal for
shallow-water wave-process experiments.
Wave dispersion will have
separated the incident swell into near-monochromatic waves, which
should be easily separable in frequency space from any locally
generated wind sea.
In addition, the continental shelf in this
area is very wide, particularly off Streaky Bay in South Australia
(33°S 134°E) where it is about 240 km from the coast to the 200 m
contour and 360 km to the 2000 m contour.
The incident swell will
already be in "transitional water depths" before the 200 m contour.
Consistently big waves should favourably increase the signal-to-
noise ratios of well-designed field instrumentation, and the com-
bination of long-period swell and a wide shelf should provide
sufficient propagation distance for clear trends in the shallow
water response to be measured."
https://drive.google.com/file/d/0BzwXRXcZyNM3ajBKOHFPU2M1VVU/view?usp=dr...
"The experiment, which was planned as a feasibility study, has
shown that the loss of energy as waves travel across the contin-
ental shelf in the Great Australian Bight can be measured.
The
preliminary results can be summarized as follows:-
A reduction in energy to about one-quarter, or a halving
of significant wave height, as waves travel the 280 km
from 1150 m water depth to 26 m depth near the coast.
No significant variation in the frequency of the peak in the
wave energy-density spectra, over the measurement line.
Energy loss appears uniform across all frequencies in the
band between 0.05 and 0.2 Hz (20 to 5 seconds period).
No significant change in the non-dimensional spectrum of a
wave-train moving from deep water towards the coast."
I was referring to previous 6-7m swells and not at all this last one . Swells that coincided with surfable type wind and surfers paddled the waves ( in SA .)
Just so nobody gets the wrong idea because the recent swell was accompanied by onshore ,unsurfed conditions . During the 6-7 plus metres on cdc buoy , So that doesn't count
Can anyone advise me of the expected sea and swell conditions on the SA and Vic coasts in DEC Jan
Far too early for specifics. Info also depends on specifics.. what are you doing? Surfing, fishing, boating etc
I have a 77' flybridge cruiser and would like to average between 12 to 16 knots and stay in safe ports every night
would like to stay in Christmas Cove Kangaroo Island on my first but unsure of the depth and size of the little bay?