Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Friday 28th July)

Best Days: Sat AM: Early S'ly swell and W'ly winds. Less consistent surf and N'ly breezes into the a'noon. Tues onwards: building S/E tending SE swells, biggest and best Wed and (more likely) Thurs. 

Recap: Strong southerly swells generated 4-6ft surf at south facing beaches on Thursday, a little lumpy at some locations but very good otherwise. Size has eased quickly overnight, with early 3ft sets at south facing beaches throughout the day abating a little more during the morning and into the afternoon. A small renewal of slightly longer period energy showed up across the Pt Kembla and Sydney buoys around dawn (earlier than expected), with peak swell periods up from an overnight 10 seconds to 13 seconds. However, it doesn’t appear to have translated to any great size increase. South facing beaches seem to be around the 2ft mark this afternoon. Models are still suggesting an increase in wave heights around 6pm this evening, so we may still see a little more size before close of business.

This weekend (July 29th - 20th)

Although this week’s long period southerly swell has dipped a little below expectations today, we should still see a continuation of this energy into Saturday. You can see this via the Swell Train Analysis (to the right), which shows periods of 13-14 seconds today, slowly easing to 12-13 seconds tomorrow. This is the natural continuation of the backside of this long running swell event.

We’ll also see a fresh short range S’ly swell in the water on Saturday morning (again, highlighted to the right), originating from a strong front exiting eastern Bass Strait this afternoon. 

This should provide a brief flush to 3ft at sough facing beaches around dawn - though it’ll be much smaller elsewhere (a little bigger the Hunter though), and it may be hard to discern anyway with the pre-existing long range energy in the water. Expect this swell to ease throughout the day, so aim for an early paddle, where we’ll also see a few hours of W’ly winds before they swing NW and then N’ly into the afternoon. However, no major strength is expected in this northerly airstream, away from the South Coast.

Note: the "estimated surf height" from our in-house model is suggesting a kick in size around 6pm, but this is erroneous - the model is combining both the long range and short range energy together, giving the false impression of a boost in surf heights late in the day. Instead, the surf will probably slowly abate from early afternoon onwards and become much less consistent too. 

With no new swell sources otherwise showing on the charts, we’re looking at a rapid easing trend into Sunday. South facing beaches may see a few stray 1-2ft sets at dawn but it could very well be flat by the early afternoon. Surf conditions will be tiny elsewhere, except for the Hunter which may pick up a few bigger bombs. It’ll be clean with mainly moderate NW winds. 

So, as mentioned on Wednesday, Saturday morning is still the pick!

Next week (July 31st onwards)

I’ve been mentioning a couple of flukey swell sources for the first few days of next week for some time now, and they’re still showing up on various charts - but there’s not enough in it to warrant close scrutiny. 

However, we have a more confident swell source for next week, and this was detailed in Wednesday’s notes - but it’s been brought forward a little earlier.

On Monday, a developing trough is expected to form a low pressure system well east of the South Coast. A northerly flow off the Mid North Coast may kick up some short range windswell into the afternoon, but unless the models really ramp up the width of the fetch (and align it a little more towards Southern NSW) I don’t think we’ll see much more than a weak foot across exposed NE facing beaches.

Of much more interest are developing southerly gales around its western flank by Tuesday morning. Now, the setup here doesn’t look ideal with most of the fetch aimed slightly north of the Southern NSW coast, however what’s working in our favour is near stationary movement in the Central Tasman Sea. This will allow secondary fronts to wrap around the low, working on the pre-existing active sea state and helping to generate bigger, better quality S/SE tending SE groundswells (following an initial short range S'ly windswell).

Now, whilst there is moderate to high confidence that a decent sized low will form in the southern Tasman Sea early/mid next week, the models have moved around on the particulars in the last 48 hours so we really need a few more days to iron our the specifics. So right now the models are estimating 3-4ft from the S/SE from late Tuesday into Wednesday and Thursday (even reaching 3-5ft Thurs AM), but there’s a chance that it could be pushed higher if the models develop the SW flank of this low a little better (personally, I am expecting somewhere in and around the 6ft mark).

I’ll update over the weekend as more information comes to hand, otherwise check back Monday for an update on how this event will pan out next week.

Looking further ahead, and the models have another Tasman Low forming off the coast later next week which should continue July's strong activity through the first week of August. 

Have a great weekend!