Strong south swell building Wednesday, peaking Thursday with good winds

Ben Matson picture
Ben Matson (thermalben)

Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Monday 8th June)

Best DaysWed: building S'ly swell, cleanest early but it'll be only small then. Thurs: strong S'ly swell with rapidly improving conditions under light variable winds. Fri/Sat/Sun: moderate, easing S'ly tending S/SE swells with light winds.

Recap: Plenty of fun waves all weekend with an easing S/SE swell, sets were still 3ft on Saturday (bigger in the Hunter) but fell to about 2ft on Sunday and it’s barely cracked a foot to finish the Long Weekend. Great conditions all days with light variable winds. 

This week (June 9 - 12)

Our swell windows have remained inactive for the last few days so Tuesday will see tiny conditions persist across Southern NSW. 

A vigorous frontal passage currently crossing Tasmanian longitudes (Maatsuyker Island off Tas’ South Coast recorded a N/NW wind gust of 84kts a short time ago, that’s 156km/hr) will be the source of our next round of swell energy. Right now this progression is still tucked inside the Tasmanian swell shadow, however two fetches will clear east into our swell window early Tuesday morning, with strong W/SW thru’ SW winds occupying the waters south from eastern Bass Strait to about 55S.

In fact, the initial system, whilst the stronger of the two fronts, is actually less favourably aligned for East Caost swell potential: the second system pushing through later Tuesday and early Wednesday morning will be on the backside of the Long Wave Trough and consequently will have a stronger meridional component (north-south). This means it’ll be aimed better into our swell window and will subsequently produce bigger, stronger swells for southern NSW.

Friday’s notes listed a remote chance of seeing a late pulse Tuesday, and I think we can confidently wipe this off the charts now: we’re likely to see the leading edge push through in the evening on Tuesday, with a slow increase through Wednesday morning ahead of a more prominent increase through Wednesday afternoon.

Unfortunately, Wednesday’s building trend will be accompanied by a wind swing from the SW around to the S during the day - although, it won’t be overly strong, perhaps 15-18kts tops - but still enough to wreck surface conditions at exposed beaches. We should see small waves early morning (2-3ft sets at south facing beaches) pushing 3-5ft throughout the afternoon, with much bigger waves across the Hunter coast - however it’ll be much smaller at beaches not open to the south. 

The biggest swell from this pattern is due on Thursday, originating from the strong secondary front. This is expected to arrive overnight Wednesday and should produce 4-6ft surf at most south facing beaches during Thursday, and up to 6-8ft in the Hunter. And, local winds are looking reasonable on Thursday, thanks to a high pressure system ridging in from the west in the early hours - some locations may see a lingering S’ly flow early morning (i.e. Hunter, Central Coasts) but for the most part winds should be light and variable on Thursday. So, there should be plenty of quality waves on offer on Thursday, just expect smaller surf at beaches not completely open to the south.

From Friday, we’re looking at slowly easing swells from the southern quadrant with light variable winds - so plenty of good options about the coast although with an abating trend. 

This weekend (June 13 - 14)

Although the weather systems responsible for our mid-week pulse will clear eastwards later in the week, the Southern Ocean south the Tasman Sea will remain active during this period which should arrest the overall easing southerly trend for the weekend. In other words, we’re likely to see slowly easing swells (rather than rapidly easing) so there should be plenty of energy both days. 

South facing beaches are expected to have fun 2-3ft options on Saturday morning with smaller surf through Sunday, however the Hunter region should pick up a little more size both days. And as for local winds and weather  - it looks like we’ll still be under the influence of a high pressure system, so winds should be light with good weather on tap too. Another good weekend for exposed south swell magnets.

Next week (June 15 onwards)

A strong series of polar lows and fronts are expected to develop south of the Tasman Sea over the weekend, which - although located towards the eastern edge of our south swell window - may provide some new S/SE swell during the first half of next week. This is however some time away and it’s common for the computer models to shunt this pattern further east as we draw closer to it (i.e. pushing it outside of our swell window). Let’s take a closer look on Wednesday.