Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Wednesday 4th July)

Best Days: Thurs/Fri: peaky E/NE swell with offshore winds. Thurs PM, Fri AM: small inconsistent S'ly swell. Sat: fun S'ly swell with offshores. Sun/Mon/Tues: large S'ly swell with offshore tending variable winds. Wed onwards: moderate S'ly swells with light winds. 

Recap: Tuesday was very small and clean. But today across Southern NSW.. well, there’s a curveball for ya. The anticipated E/NE swell kicked in this morning with much more size and vigour than expected, showing much earlier than modelled and surpassing even my expectations for an upgrade on top of Monday’s estimates. We saw a wide variety of size across the coast, but many NE facing beaches picked up 4-5ft sets and there’s been evidence of occasional 5-6ft bombs at times, and conditions were clean with light offshore winds. This size is very surprising, as it’s sourced from a low off the Far Northern NSW coast that delivered similar waves heights to that region yesterday (4-6ft northern NSW, 3-4ft Gold Coast etc) - of which the fetch was better aimed, and closer to those coasts - so proportionally should have translated to much less size across Southern NSW. Yesterday’s satellite winds (see below) didn’t pick up any unusual features suggestive of a much stronger than expected E/NE pulse either. I’ll review the hindcast data when I get a moment to see if there are any clues that slipped through the net.

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Yesterday's satellite winds: nothing out of the ordinary for Southern NSW

Lovely E/NE swell on the Cenny Coast this morning, via our new Avoca surfcam

This week (July 5 - 6)

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Note: Today’s Forecaster Notes will be brief, as Craig is away on annual leave

Confidence in the outlook for Thursday has plummeted. Main reason being: Monday’s read on the synoptics had anticipated a broad, slow upwards trend through today, plateauing into Thursday morning, then easing from Friday.

Taking today’s conditions into account, the first process is to determine whether we should we anticipate the same trend (as per Monday's notes), and then compensate by adjusting the size upwards by a couple of feet for Thursday and Friday.

Or, do we dismiss today’s pulse as an as-yet unexplained aberration amongst an otherwise slow building E/NE trend, and then stick to the same broader outlook as was issued Monday.

Because (in the very short time I have available right now) I’ve been unable to find the primary source of today's pulse. And it’s hard to imagine that there’s two days worth of 4-5ft+ surf for our region from this low.

Whilst it makes sense to bump up wave heights from previous forecasts, you certainly don’t want to overcompensate and therefore overcall Thursday’s waves. On the flip side, local buoy data and surfcam obs show that wave hights have already dropped from the morning peak, which supports the latter theory (to stick with Monday's estimates).

The good news is that regardless, we’re looking at light offshore winds and clean conditions. And the afternoon will also herald the arrival of a small, flukey long period south swell that’ll provide good surf late afternoon and into Friday.

So based on this, I’m going to hold around 2-3ft+ at most open NE facing beaches from Thursday into Friday morning, easing throughout the day. Our model (which admittedly failed to pick up today’s swell) actually has slowly build swell periods throughout this time frame, akin to an anchored trade pattern, though with decreasing swell size. 

The new flukey south swell should also be worthy of occasional 2-3ft sets at south swell magnets, however Friday is a better day for this. We’ll also see strengthening NW winds across the coast as a series of fronts push through Bass Strait.

Anyway, I will be very interested to see how tomorrow pans out!

This weekend (July 7 - 8)

Easing swells are expected over the weekend, and with a succession of strong fronts pushing across the SE corner of the country it’s going to be clean both days with offshore winds from the NW tending W then SW.

A strong front exiting eastern Bass Strait on Friday afternoon will generate a fresh south swell for Saturday, that’ll be biggest across the Hunter with 3-4ft sets, smaller across Sydney’s south facing beaches around 2-3ft, and smaller again at remaining beaches. It'll be inconsistent at times, however there will also be some small leftover E/NE swell in the water too. 

A powerful front will then enter the lower Tasman Sea on Saturday evening, driving S/SW gales adjacent the coast and generating a large south swell for Sunday that could push 5-6ft+ at south facing beaches, though much smaller elsewhere due to the swell direction. Winds will veer more to the SW across most regions in association with the front but it’s expected to clear quickly to the east and we’ll see moderate W/SW thru’ W’ly winds settle in throughout the day. 

More on this in Friday’s update. 

Next week (Just 9 onwards)

An active node of the Long Wave Trough is driving powerful fronts into WA at the moment, they’ll impact SA later this week and Victoria over the weekend, before finally pushing through the lower Tasman Sea later this week as the LWT moves further to the east. 

This will set up a broad, heavy fetch of southerly gales aimed right through our south swell window, and they’ll generate a couple of days of very large surf at south facing beaches in the 6-8ft range (Mon/Tues).

Secondary fronts trailing behind will maintain moderate southerly energy through the rest of the week, and the entire period is looking really good on the surface with mainly light winds. 

As such, you’re looking at a solid workout for your favourite south swell magnet - they’re going to be sizeable for quite some time.