Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Wednesday 9th December)

Best Days: Thurs: Early light winds, small easing S'ly swells. Sat/Sun: patchy conditions but plenty of E'ly swell. Mon/Tues: very large from the E/NE but likely quite onshore. Wed: large, easing E/NE swell with light winds, smaller Thurs. Fri onwards: extended run of E/NE groundswell.

Recap: Southerly windswells built through Tuesday, reaching a bumpy 3ft+ at south facing beaches late afternoon though surf was much smaller earlier. Early light W/SW winds kicked in from the south at strength mid-late morning across the Sydney region, but eased back to become light W’ly this morning as the S’ly swell eased slowly from 2-3ft at south facing beaches. Late this morning, a new longer period S’ly groundswell (peak swell periods 13.8 seconds) reached the Sydney region and has built to 3-4ft at south facing beaches, though freshening afternoon E/NE breezes are creating unwelcome bumps. Surf size is much smaller at beaches not open to the south.

Nice S'ly lines on the Cenny Coast this arvo... shame about the onshore wind

This week (Dec 10 - 11)

The rest of the week looks a little patchy. 

Today’s S’ly groundswell isn’t expected to last long, and will ease slowly overnight and through Thursday. The current NE breeze should ease in the early hours of Thursday morning to become light and variable for the dawn patrol, so conditions are likely to be clean (if a little lumpy), ahead of a gusty S’ly change expected into Wollongong around 10am (give or take), reaching Sydney before noon and strengthening to 25kts into the afternoon.

As such, with the afternoon expected to be a bumpy write off (though with a late windswell increase), the early session is more preferable. South facing beaches may see rare 2ft, maybe 2-3ft sets - the upper end of this size range across the Hunter - but other beaches will be tiny thanks to the acute swell direction.

A stalled trough across Northern NSW on Friday and a building ridge of high pressure to our south will maintain fresh S/SE winds through Friday. South facing beaches should see 3-4ft sets but quality will be hard to find. Southern ends will be smaller but slightly more manageable. We’ll also see less wind south from Wollongong, but also a little less size. So, it’s not worth getting too excited about.

This weekend (Dec 12 - 13)

We’ve got a heck of a lot of easterly swell on the way, but the weekend will be generally much smaller than the sizeable energy due next week.

Just to recap Monday's notes - another series of fronts below Tasmania over the coming days will generate small sideband south swells for the weekend, perhaps 2-3ft at south facing beaches both days. 

Elsewhere, and a stationary ridge of high pressure will linger across the southern Tasman Sea from Friday through much of next week, cradling a deepening trough across the Coral Sea. This trough - or E’ly dip, as it’s expected to evolve towards within a few days - will slowly track S/SW all weekend, roughly parallel to the NSW coast, directly through our swell window. It's an exciting synoptic chart. 

Initially, the early stages of this pattern will maintain moderate E/SE swells across the region, building from 2-3ft early Saturday to 3-4ft through the afternoon, and then from 3-4ft to maybe 4-5ft by very late Sunday. 

Winds will be out of the eastern quadrant all weekend, but apart from the Hunter region, speeds shouldn’t be too great so there should be some workable options here and there (mainly southern ends, and point breaks). But, it certainly won’t be fantastic on the surface. There’ll be less strength in the onshore breeze south from about Wollongong, though we’ll also see less size too (thanks to the increased distance from the swell source). 

So, lots of options - just gotta lower your standards!

Next week (Dec 14 onwards)

The approaching E’ly dip is expected to be quite a strong system and its close proximity to the mainland will ensure very little size loss. However, it also means we’ll see periods of strong onshore winds, probably accompanying the height of the swell. 

At this stage, late Monday and early Tuesday is likely to see the peak activity - probably somewhere north of 8ft+ at exposed beaches, but local conditions will probably result in very few surfable options. 

But, aside from potential coastal erosion (we’ve got a 2m+ high tide 9:20am Tues), the backside of this swell will probably provide the best waves. The reason is that the trough/E’ly dip will weaken later Tuesday, allowing local winds to abate and become light and variable into Wednesday, cleaning up surface conditions. 

There won’t be any shortage of surf either. The tail end of the associated E/NE fetch will remain active through Monday and Tuesday, and in fact because it’ll be slow moving, it should enhance wave heights compared to an otherwise mobile fetch. So even though our model is calling surf size to ease to 3-5ft Wednesday morning, I suspect it’ll be well north of 6ft+ for most of the day, easing to 3-5ft on Thursday as winds veery S’ly undere the influence of a weak front.

And it doesn’t end there.

Over the weekend, a tropical cyclone is expected to develop north-west form Fiji, and then slide south to about Vanuata’s latitude by Monday. Whilst the models are not yet confident on whether this cyclone will actually push clear into our swell window, a major supporting ridge stretching form the northern Tasman Sea all the way back into the South Pacific will maintain healthy E/NE swells for the long term, building from Friday through Monday of the following week, and likely holding for a few days at strength. 

Early indications are that surf size won’t drop below 3-4ft for this entire time frame, and could peaks near 5-6ft+ around Monday - and that's without any direct enhancement from the cyclone. If the cyclone drops into our swell window, then the size potential will only go up more - it’s a big, beefy system whose slow moving characteristics close to the mainland are ideal ingredients for a very significant easterly groundswell event. But, let's not get ahead of ourselves just yet.

So, waves for days! And no need panic around the first few pulses either, you’ll need to conserve energy for the long haul.

See you Friday!