Multitudes of south swell

Ben Matson picture
Ben Matson (thermalben)

Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Wednesday 12th August)

Best Days: Late Thurs/Fri: fun mix of south swells with generally good conditions. Sat/Sun: small clean south swell(s) with light winds (except Sat PM). Late Mon/Tues: chance for a small funky SE swell. Tues thru' Fri and beyond: series of southerly swells. 

Recap: Monday’s south swell eased very slowly through Tuesday and we’ve even seen a few lingering sets persist into today. Conditions have been clean with light variable winds Tuesday and this morning tending gusty offshore this afternoon.

This week (August 13 - 14)

We’ve got plenty of interesting swell sources lining up for the next few days. 

A cold front is currently pushing off the coast, and although winds are presently westerly right across the region, we’ll see a south-west flow develop parallel to the Southern NSW coast early Thursday morning as the front tracks further east. This will generate a new south swell for the region, although its primary direction will be SW, aimed away from the mainland - so we’ll see a smaller spread of energy at the coast.

Additionally, the fetch will develop in an unusual fashion due to the presence of two fronts - the South Coast front and another rounding the Tasmanian corner (in the Southern Ocean).

Ordinarily, these systems track up the coast and the trailing fetch works on top of the sea state generated by the headwinds. However in this case the broader south-west airstream is modelled to develop inside our swell window between the two fronts (the southern front will merge into the northern system) and this will probably reduce its impact on the surf department as it’s not expected to last very long in the window.

As such, the overall trend will be starting from a tiny base early Thursday, building throughout the afternoon towards a peak very late in the day. I’m expecting around 3ft+ at south facing beaches (bigger in the Hunter, but smaller 1-2ft surf at locations not completely open to the south). My earlier concerns of winds swinging SW then S/SW throughout the afternoon have diminished in recent model runs - it can’t be completely ruled out but chances are that most locations will now hold from the W/SW or SW. 

On Friday, surf size is likely to slowly taper off throughout the day, following a morning peak. I’m now less confident that we’ll see a secondary pulse from the Southern Ocean front (latest model guidance pushed its fetch just inside the swell shadow of Tasmania), so wave heights will probably trend downwards from the get go. Conditions should be very good though with light W’ly winds across most regions, tending variable throughout the day. South facing beaches should see early 3ft+ sets with much smaller surf at beaches not open to the south, but a few bigger bombs in the Hunter.

This weekend (Aug 15 - 16)

There’s still nothing major on the cards for the weekend at this stage, however we should see fun waves both days.

Friday’s south swell will continue to ease slowly into Saturday and early offshore winds should maintain clean conditions at most beaches, with sets in the 2ft+ range. A weak front is expected to clip the coast during the afternoon, probably swinging winds around to a moderate to fresh southerly after lunch, so if you’re aiming to surf on Saturday make it early. Also, keep in mind that locations not directly open to the south will be considerably smaller. But the Hunter should see a few bigger sets.

This weak front will quickly dissipate and clear to the east, leaving Sunday sunny and clean with light variable winds. A small new south swell trailing the front should maintain fun peaky waves at south facing beaches in the 2ft+ range (again, smaller elsewhere but a little bigger in the Hunter). It’ll hardly be epic but there should be some fun beach breaks up and down the coast to finish the weekend.

Next week (Aug 17 onwards)

The weak front expected to push into the lower Tasman Sea on Saturday is now modelled to form a new low off the West Coast of New Zealand’s South Island on Sunday, and although poorly aimed for Southern NSW, should generate some sideband energy for the first half of next week. It’s too early to have confidence in this as a priority swell event but early indications are for late Monday or Tuesday to see clean 3ft sets from the SE. 

Additionally, the middle part of next week (Tues thru’ Thurs) is expecting to see varying degrees of southerly swell, originating from several sources - a couple of distant, broad polar lows skirting the Southern Ocean, and a close range frontal passage through the lower Tasman Sea around Tuesday. At this stage there’s still not much confidence on how much size we’ll see so I’ll update the figures on Friday. 

Beyond this, a similar pattern is expected to maintain plenty of long period southerly swell through the end of next week and next weekend. More on this in Friday’s update.