Plenty of S'ly swell but windy at times; Sunday the pick

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Ben Matson (thermalben)

Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Wednesday 17th June)

Best Days: Thurs AM: early offshores and a small combo of NE and SE swells. Fri/Sat: strong S/SE swell but winds look dicey. Sun: combo of easing S/SE swell and steady S'ly swell with light winds. 

Recap: Plenty of S/SE tending SE swell on Tuesday with 3ft+ sets at many beaches, ahead of a slow easing into today. A small new NE windswell has built into today with early N’ly winds tending NW. Set waves from this source have come in a little bigger than expected, pushing the 3ft range.  

This week (June 18 - 19)

A broad trough developing across the southern Tasman Sea is expected to form two centres of low pressure over the next 36 hours. One low will form off the South Coast and track steadily E/SE to be positioned near New Zealand’s South Island by late Thursday; a second low will form off the Mid North Coast early Friday and move E/NE into the northern Tasman Sea. 

Across the southern flank of this broad trough, fresh to strong southerly winds will develop across the southern Tasman Sea through Thursday and are expected to generate a new south swell for the region during the day. However, accompanying southerly winds will unfortunately ruin the surf at exposed locations.

We’re looking at an upwards trend all day Thursday (starting from a small base of residual NE and SE swell from today, with early westerly winds), and by late afternoon should be holding 3-5ft at south facing beaches - but with gusty S/SE winds on hand. Wave heights will be much smaller at locations protected from this wind.

On Friday, the southerly wind regime will continue but should ease in strength, possible allowing for a period of light variable winds in selected areas early morning (i.e. Northern Beaches). But for the most part, local conditions are expected to be a little ragged on the surface. We’ll see plenty of S/SE swell somewhere between 4ft and occasionally 6ft at south facing beaches, with better waves at protected locations around 2-3ft.  Keep your expectations low and you should do OK. 

This weekend (June 20 - 21)

The developing low off the North Coast on Friday will maintain a moderate southerly airstream about southern NSW on Saturday, before winds swing light and variable on Sunday. As such, surface conditions aren't looking especially flash for the first half of the weekend

However, the weekend is looking pretty strong surf wise, with a combination of slowly easing S/SE swell from the low off New Zealand’s South Island on Saturday, plus an additional long range southerly groundswell arriving in the afternoon, originating from a strong frontal passage below Tasmania on Thursday. This should maintain 3-5ft waves at south facing beaches for most of the day however local winds may spoil conditions somewhat. 

On Sunday we’ll see slightly smaller surf - a quickly easing S/SE swell with a level S’ly groundswell - and wave heights should manage 3-4ft at most south facing beaches. However, due to the dominant south swell in the water we’re likely to see bigger waves across the Hunter (which usually performs very well under this synoptic scenario) so I wouldn’t be surprised to see occasional 4-6ft waves here at times.

Either way, Sunday should produce the better conditions of the two days with mainly light variable winds and smoother conditions. But Saturday’s not looking too bad, especially south of Sydney where there’s less likely to be any influence from the synoptic southerly attributable to the low to the north. 

Next week (June 22 onwards)

Generally easing surf is expected early next week with a high pressure system moving into occupy the Tasman Sea. We’ve got a couple of possible swell sources for next week though: the North Coast low looks like it’ll linger within a broad troughy feature across the Northern Tasman Sea for a few days, and may briefly re-intensify into something of a swell-producing nature. However, the models are a little flaky on this scenario right now so let's give it a few days before discussing possibilities.

Elsewhere, we’re looking at a southerly change later Tuesday that may deliver some short range southerly energy mid-week. And a series of strong fronts below the continent should keep south facing beaches from becoming too small. However mid-next week is still quite some time away so let’s wait and see how the models pan out on Friday.