Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Friday 26th August)

Best Days: Sat AM: small clean leftovers at exposed beaches. Mon: small,clean but inconsistent S'ly swell with light winds. Tues/Wed: building long period S'ly groundswell, but the arrival time is tricky, and winds are expected to be out of the north. Late Tues looks best for the South Coast; early Wed for the Sydney/Hunter region. 

Recap: The last few days ended up being a little bigger than expected, and conditions improved more rapidly on Thursday than was initially thought. The E/SE swell from the Hunter trough/low produced 3-4ft surf (against a forecast of 3ft) across most beaches from the Hunter coast down to about Wollongong, and winds swung offshore overnight Tuesday, leading to clean conditions from the get-go across most regions throughout Thursday, apart from a few hours of southerly deviation into the afternoon. Today this E/SE swell has eased back and we’ve seen a small new southerly swell fill into exposed beaches, and surf size has once again punched above its weight with some 3-4ft sets seen at south swell magnets (a little surprising TBH, given the source). Early offshore winds have given way to moderate to fresh southerlies this afternoon.

This weekend (Saturday 27th - Sunday 28th)

I’m still not confident for any major surf this weekend. 

The good news is that a building high pressure ridge will push this existing troughy pattern (and the accompanying southerly) out into the Tasman Sea, leaving us with clean conditions under a light variable breeze. Westerly winds will briefly freshen overnight on Saturday as a front clips the SE corner of the state, but it won’t really affect most regions apart form the South Coast, leaving us with variable winds both mornings and light to moderate sea breezes in the afternoons.

As for surf - there are no new swells of any significance on the way so we’re looking at small residual energy both days. Inconsistent 2ft+ sets are likely through Saturday morning (mainly south facing beaches), with a few bigger 3ft+ bombs across the Hunter, but it’ll ease in size as the day progresses. Slightly smaller surf is expected into Sunday. And beaches that aren’t completely exposed to the south will be smaller.

A new long period S’ly swell is showing up on the charts for the South Coast late Sunday but as per Wednesday’s notes, I’m a little suss on its origins - the polar low expected to generate it never really showed any strength so I am skeptical we’ll see anything major (certainly not the 16+ second peak periods suggested in the model guidance). 

In any case, this swell is forecast to arrive too late in Sydney to be of any benefit, so it’s really not worth worrying about. High volume boards will be your best friend this weekend!

Next week (Monday 29th onwards)

So, will this small long range southerly swell provide a kick in new energy or not?

Actually, the models have two long range swell from the southern quadrant in the water for Monday (one at 15 seconds, another at 16 seconds) but it’s very hard to have any confidence that they’ll eventuate. 

In fact I have a feeling that most of Monday’s surf will probably be mid-period energy originating from the fetch trailing the front due to cross Tasmania overnight on Saturday. The fetch doesn’t look amazing, but we can’t rule out south facing beaches picking up very infrequent 2ft sets, maybe some 2-3ft bombs from time to time (the upper end of this size range more so in the Hunter than anywhere else though). Expect smaller surf at remaining beaches form this source. Winds will be light and variable for much of the day so conditions will be clean. 

A weak low is expected to form in the central/northern Tasman Sea on Saturday - actually the reincarnation of our most recent coastal system - but it looks too small, and aimed too far to the north to benefit us. However small lines out of the east are possible at open beaches on Monday (no more than a slow 1-2ft, unless the models upgrade this system).

Otherwise, we’re still on track for a solid long period south swell some time on Tuesday.

Since Wednesday’s notes, the models have made a few adjustments - they’ve actually strengthened the core of the parent low, but kept it a little further south, and aligned it slightly more zonal (west-east). And this system will now reach peak intensity whilst existing to the east of our swell window, which is less favourable for us. 

So, despite the stronger surface wind field - and therefore larger peak swell periods we’ll see at the coast - the other factors have forced me to slightly downgrade the surf potential from this system. And the adjustments have also pushed back the peak of this swell to Wednesday morning across Sydney beaches.

The leading edge (18+ seconds) is expected into the South Coast on Tuesday morning and then into the Sydney and Hunter Coasts on Tuesday afternoon, so we should see a solid kick a few hours after that - probably into the 3ft+ range, but very inconsistent.

However the largest size from this swell will be in the mid-period bands (14-16 seconds), located some 12-18 hours behind - which is expected to peak on Wednesday morning (probably overnight across the South Coast). South facing beaches should see 3-5ft sets from this source early morning, before easing during the day.

I’m a little worried about the scope and reach of this swell, and have a feeling it’ll be quite selective in where it focuses the biggest waves. But with large peak swell period we can’t rule out significantly larger waves at offshore bombies (i.e. well north of 6ft).

It's a shame, because had this fetch been aimed more meridionally in alignment (i.e. south-north) it would have produced a substantially bigger swell event for Southern NSW. By way of an example, New Zealand is going to get smashed by this swell event and even distant South Pacific haunts such as Tahiti will see a very large long period SW swells next weekend.  

Anyway, Monday will be a much better time to properly evaluate this swell, as we should have good satellite data in by this time. So for now, pencil in a late session on Tuesday - there’s certainly a chance this swell could provide bigger waves late in the day than what I’ve mentioned above - but Wednesday morning looks like your best bet. 

As for local winds, Tuesday looks tricky with freshening N tending N/NE airstream, whilst Wednesday should see winds veering NW at some point as a front approaches from the west. So again, Wednesday is the pick for now on all counts.

Tuesday’s northerlies should also create a peaky NE windswell for Wednesday morning, though the southerly groundswell is expected to be the dominant swell source in the water. 

Other than that there are no other major systems on the charts. I’ll be keeping an eye on the South Pacific region NE of New Zealand mid-next week as the models are suggesting a deepening trough (and possible E’ly swell source for next weekend) but it’s still early days. 

Have a great weekend, see you Monday!