Go the Souths!

Ben Matson picture
Ben Matson (thermalben)

Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Monday 29th June)

Best Days: Entire period: great waves expected pretty much every day. Wed PM, Sat and Mon the pick.

Recap: Very small waves were present on Saturday and Sunday. The only noteworthy aspect being a small, very distant long period south swell that pushed across the coast on Sunday that was the byproduct of intense Southern Ocean storm activity, well outside our swell window. As such the surf was very small. Today we’ve see a much stronger S’ly swell fill in as expected, with 3-4ft sets showing up across south facing beaches and bigger waves in the Hunter. Conditions have been clean all day with light offshore winds. 

This week (June 30 - July 3)

We’ve got an extended period of south swells lining up for Southern NSW, with generally good conditions most days. 

The key aspect of this coming forecast period will be nailing down the individual timing of each swell front, as they’ll each react differently across the various reefs and beaches. Estimating precise wave heights is harder than normal for this series of swells, because several of the swells are being (or will be) generated by very powerful low pressure systems that are poorly aligned within our swell window. This means that we’re having to estimate the percentage of sideband energy that’ll reach the NSW Coast, which always requires some elasticity. 

So, on to the particulars, and as detailed throughout much of last week we’ve got three distinct pulses due this week, spaced roughly two days apart. Today’s swell will ease slightly through Tuesday but south facing beaches should still see leftover sets in the 3ft range throughout Sydney, and initially between 3ft and 5ft across the Hunter Coast. It'll likely ease slowly in size during the day, and will be very inconsistent too. But conditions should be clean with mainly light winds out of the northern quadrant.

On Wednesday, we’ll probably start the day off with similar residual south swell (maybe a little smaller than Tuesday afternoon) but new long period S’ly swell is expected to filter into the South Coast around dawn, and up until Sydney mid-morning, generated by an intense low currently tracking south of the Tasman Sea (see chart below). 

It’s not very well lined up but core wind speeds were recorded by satellite over the weekend in the 50-60kt range, over quite a distance (well SW of Tasmania). The sheer strength of these winds and the active sea state they were working on means there’ll be one heck of a large, long period swell event generated and even though it’s aimed into the South Island of New Zealand, we’ll see a healthy spread of size back into the Australian East Coast. Peak swell periods associated with the leading edge will probably come close to 19-20 seconds which is a rare occurrence in these waters.

Wave heights should push upwards of 3-4ft+ across Sydney’s south facing beaches through the afternoon - with the biggest waves on dusk - and with the Hunter usually performing very well under these kinds of south swells, we should see easy 6ft+ bombs through the afternoon across this stretch (some offshore bombies across the Sydney region should also see some bigger waves). However beaches with less southerly exposure will be smaller. 

Note: our swell model really isn’t picking up this event very well. It is showing strong periods but with a small associated size of just half a metre.. I think we’ll see probably double this size (about a metre at 18 seconds as the bulk of the swell fills in). Nevertheless, as mentioned above confidence is lower on estimated surf sizes from poorly aligned systems so it’ll be interesting to see what eventuates. Conditions will be clean all day with light winds. 

On Thursday, this swell event will trend downwards but I wouldn’t be surprised to see a few lingering 3ft+ sets at south facing beaches early morning, with bigger 6ft bombs in the Hunter. However the overall outlook for the day will be for an easing swell, and an early W’ly breeze tending gusty SW and strengthening as a vigorous front crosses the Tasman Sea. 

I think this front will push through our swell window too late to generate any new swell on Thursday, so Friday is where we’ll see all of the size from this source, of which we’ll see a large day of waves originating from two regions: the near S/SW fetch across the western Tasman Sea, and also a strong, broad fetch of winds stretching from the ice shelf up into the lower Tasman Sea. This will ensure not only a strong swell event, but also a sustained one too.

The main concern with Friday centres around the local winds. Although the front will be quickly clearing to the east, there’s a reasonable chance - especially across the Hunter - that we’ll see a lingering S/SW flow about the coast. South from the Northern Beaches, we’re more likely to see early W’ly winds tend moderate SW. But up in the Hunter a sou’wester is cross-shore at many breaks. 

As for size on Friday, we’re looking at around 4-6ft at south facing beaches in Sydney, with larger 6ft+ waves in the Hunter. Again, beaches with less southerly exposure will be smaller. Either way there’ll be plenty of waves to finish the working week.

This weekend (July 4 - 5)

The weekend looks excellent. 

As mentioned above, the broad system generating Friday’s waves will extend all the way to the ice shelf, and it’s this part of the fetch that’ll generate quality long period energy for Southern NSW on Saturday and Sunday. It won’t be quite as big but south facing beaches should pick up 3-5ft waves both day, pulsing in and around this range, with occasional lully periods.

Winds are looking to be light and variable, probably W/NW Saturday ahead of a brief, shallow SW change in the afternoon and a variable trend on Sunday.

Another strong, long period S’ly swell is expected to round the Vic/NSW border on Sunday afternoon and may provide some bigger waves for the Far South Coast (and maybe South Coast) late in the day but this next swell probably won’t reach Sydney latitudes until nighttime.

Next week (July 6 onwards)

Sunday’s late arrival of new S’ly swell on the South Coast will originate from yet another deep Southern Ocean low tracking south of Tasmania. In similarity to what’s expected over the coming days, we’re looking at light winds and 3-4ft+ of strong swell at Sydney’s south facing beaches (on Monday) with bigger 6ft+ bombs across the Hunter under a light variable airstream. This swell will then ease into Tuesday.

Beyond this, further frontal activity is expected to develop across the Southern Tasman Sea but the size and scope is as yet unclear. Nevertheless we’ve certainly got the south swell machine cranked into fifth gear, so you should be able to get into a good repetitive pattern at locations that enjoy this swell direction. See you Wednesday!


thermalben's picture
thermalben's picture
thermalben Tuesday, 30 Jun 2015 at 6:55am

A lovely study in refraction this morning via our Cronulla Beaches surfcam.


thermalben's picture
thermalben's picture
thermalben Wednesday, 1 Jul 2015 at 4:46pm

Today's south swell seems to be running rather late, and erratic buoy data isn't helping confirm its arrival.

However we've definitely seen an increase since this morning with a few 3ft+ sets starting to show at Bondi now (see bloke far right below). Just preparing today's notes right now but looks like the bulk of it will push through overnight. Argh!