NE windswell followed by strong S change

James KC

Sydney Hunter Illawarra Surf Forecast by James Casey (issued Wednesday 10th March)

Best Days: Friday and Saturday with NE swell, and variable N winds. Saturday afternoon with longer period S swell in afternoon. 


  • Quiet period of waves continues into Thursday 
  • NE swell begins to build late Thursday into Saturday peaking Friday
  • Long period S pulse late Saturday
  • Bumpy S wind swell from Sunday onwards


Tuesday we had the last of that S swell provide some clean 2ft waves in the morning. The high tide made it slow early but there was a window before the wind swung around to the S/SE that conditions were really quite nice. The afternoon was junk.

This morning was probably the worst morning of waves we’ve had for a while. Small and onshore for most places, lucky to be 2ft on the sets. The Hunter was the anomaly seeing waves up to 3ft and workable with ESE winds. 

Into the weekend

We have a broad high pressure system straddling the southeast of the nation and extending into the Southern Tasman over the next few days. A trough will extend to the coast and create a wet couple of days but pinch the ridge of high pressure and help whip up some NE winds and a subsequent NE swell for the end of the week. 

Tomorrow we will see onshore winds swing around to the N as the high shifts out into the Tasman. It’ll be light early but with next to no waves on offer I wouldn’t get too excited. 

The NE breeze will build into the afternoon and this is where we will see the swell start to build.  

By Friday afternoon we should see waves build to 2-3ft for the Hunter and Sydney, 3-4ft for the Illawarra. It’ll be interesting to see if we get anything bigger as the trough pinches the ridge creating a little ramp up of winds out to sea. 

Meanwhile closer to the coast winds will be N early, tending NW around the mid morning. This could be a nice little window of cleaner conditions before NE winds strengthen into the evening.

Saturday will see NW winds early and with that NE swell slowly easing there should be some decent waves to be had early.

The NE wind will strengthen into the afternoon but don’t give up on the waves. A longer period S groundswell will show up late dishing out 2-3ft sets at S swell magnets for Sydney and the Illawarra and more like 3-4ft sets for the Hunter. 

This source of this S swell is a tricky one to identify. A polar low, currently SW of Tasmania, will generate the swell and it'll follow the great circle path up to our coastline. It'll be inconsistent due to the long distance it has covered but it'll be powerful.

Sunday Onwards

A strong S change will arrive pre dawn for the Illawarra and Sydney. For the  the Hunter there’ll be a small window around dawn with W winds ahead of the change.  It’ll be all over by about 8am as the S change chops things up quickly. 

This S change will bring a messy 3-4ft wind swell by the afternoon but with strong S winds accompanying it you’ll need to hit southern corners where less swell will be getting in.

Winds will remain out of the S to SE until Wednesday with just the mornings providing a bit of reprieve. Tuesday looks like it’ll be the cleanest with SW winds early before swinging back around to the SE by mid morning. 

Further Ahead 

An E/SE swell could provide some solid waves later in the week hitting that 3-5ft mark but it will depend on where the trough deepens in the Tasman. Don't get too excited though as at this stage it looks like winds will be an issue.


sean killen's picture
sean killen's picture
sean killen Wednesday, 10 Mar 2021 at 7:51pm

Can anyone explain or have a theory on why the blue bottles are more frequent on SE winds than NE winds lately ( last 2 years) is there a current change or what is it?? .. any SE OR E wind guaranted blue bottles love to why ??

teaqueue's picture
teaqueue's picture
teaqueue Thursday, 11 Mar 2021 at 7:27am

I’ve been wondering too, and I want to say that everywhere on our coast has open water to its NE, where our Blueys usually come from, so surely they can come from the SE too.

But if anyone is clevererer than me - I’d like a solid answer. Been wondering. .

Craig's picture
Craig's picture
Craig Thursday, 11 Mar 2021 at 8:03am

Blueys mostly originate from tropical waters and are at the whim of the winds.

So for Sydney this means they usually arrive out of the north-east when the winds are feeding deep from the central-northern Tasman or even further afield.

But as we've seen through this past summer, there've plenty of troughs and dips in the Tasman Sea, and this could see the blueys blown south-west into the central or southern Tasman (from tropical waters), only to be blown back into the coast with south-east winds.

Also we've had that big warm pool sitting off the southern NSW coast and they could have spawned there. I'm not across the conditions they need to form and grow though.

So yes, for the most part they arrive from the north-east but can come from any onshore wind direction if they've been seeded further south into the Tasman Sea.

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tack616 Friday, 12 Mar 2021 at 12:17pm

Just to add onto this. I have a theory for Newcastle that the beaches face far enough into the south that the NE winds blow the Bluebottles down but S winds push the Blueys into the actual beaches. From memory I really only see Bluebottles in Newcastle from Southerly winds.

sean killen's picture
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sean killen Thursday, 11 Mar 2021 at 9:35am

Cheers Craig thanks much appreciated

Goodvibes61's picture
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Goodvibes61 Friday, 12 Mar 2021 at 12:23pm

The predicted NE push for Friday hasn't eventuated here in the Gong. It's a very weak 1-2ft and dribbly. Should we downgrade our expectations heading into Saturday morning?