Pumping swell from the south

Ben Matson picture
Ben Matson (thermalben)

Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Wednesday 1st October)

Best DaysThursday: fun easing south swell with morning offshore winds. Friday: building S'ly swell, possibly large late a'noon. Saturday: large, easing S'ly swell with NW tending NE winds. Sunday: moderate, easing S'ly swell with NW winds.

Recap: Tiny conditions began proceedings on Tuesday, but the expected long range E/SE swell arrived on cue mid-afternoon with inconsistent 2ft+ sets across exposed beaches (a smidge bigger than expected) and a moderate N/NE wind. This swell persisted into this morning (plus a small degree of NE windswell) with plenty of 2ft waves across open beaches however strong SW winds limited surf options at open beaches. Winds then swung S/SE through the middle of the day, and we’ve subsequently seen a strong increase in bumpy short range S’ly swell at south facing beaches, around 3-5ft. 

This week (Oct 2-3)

Thursday looks pretty fun all round. The fetch trailing today’s southerly change is quite broad, and although we’ll see wave heights slowly taper off tonight, it should maintain good 3-4ft waves at south facing beaches in the morning (with bigger sets across the Hunter). 

Additionally, conditions will be clean under a light westerly breeze, so get in early as moderate north-east winds are expected through the afternoon (conditions should be pretty good up until lunchtime though). Just keep in mind that beaches not open to the south will be smaller in size.

On Friday we’ve got another decent day of waves lining up. In the morning, surf size is expected to linger around 3-4ft at south facing beaches (bigger in the Hunter), originating from Thursday’s swell source as well as a reinvigorated SW fetch expected to develop off the South Coast throughout Thursday.

However, at some point during the day - and I’m not totally confident on the timing right now - the leading edge of a long period southerly swell is expected to arrive, originating from a powerful low/front tracking through the Southern Ocean right now.

However, the way this system approaches and develops (in the forecast models) through the lower Tasman Sea is a little different to what we often see, thanks to the current southerly change which has activated the ocean ahead of it, and of which its fetch trails back into this next system. So there's essentially an uninterrupted expanse of swell-generating winds from Wednesday thru' Friday across our southern swell window (albeit not well aligned for southern NSW at times).

What this means is that rather than a defined swell front pushing northwards along the southern NSW coast during Friday, we’ll probably see multiple swell trains building out of the south - leading to a gradual increase across the surf zone throughout the day. At this stage there’s a reasonable chance that we’ll see some sets in the 5-6ft range across south facing beaches in Sydney by the end of the day (earlier along the South Coast), and bigger sets in the Hunter.

But at this stage the peak of this swell event is expected to arrive on Saturday morning. So I've slightly downgraded size expectations for the latter part of Friday.

As for winds on Friday - they’re looking pretty good overall. The models are tipping a light onshore flow (thanks to a weak coastal trough) but I’m pretty confident that we’ll see local topographical influences steer the morning’s winds around to the west in most areas. Just be wary though that light to moderate easterly winds could spin up at any time, which will deteriorate surface conditions if this happens.

This weekend (Oct 4-5)

We’ve got an excellent weekend of waves, as long as you like solid south swells and winds out of the northern quadrant. 

Saturday morning is currently expected to see a peak in size, with south facing beaches in Sydney between 6ft and possibly 8ft, whilst offshore reefs and exposed parts of the Hunter coast should see sets near 8-10ft at times (obviously, beaches not open to the south will be much smaller, around 3-5ft at most open locations with 2ft+ surf inside sheltered southern corners). Surf size will slowly ease during the day.

Wind wise, we’re looking at early NW winds tending moderate N’ly through mid-late morning then fresh NE into the afternoon. So you’ll need to hunt around for the right combo but there should be no shortage of solid swell on offer.

Sunday’s looking better on the surface with moderate to fresh NW winds all day and a slowly easing S/SE swell, between 3-5ft at south facing beaches early (a little bigger in the Hunter) but smaller at beaches not open to the south. Size will slowly taper off during the day and the swell will become less consistent but there’ll be great waves at most open beaches. Well worth your effort.

Long term (Oct 6 onwards)

Still nothing major on the charts at this stage, however we’re looking at a couple of quick fronts skirting the lower Tasman Sea on Sunday and early Monday that should produce some small southerly energy for the first half of next week.

Strengthening N’ly winds are likely to whip up a peaky NE windswell for Tuesday; and beyond that it looks like another strong frontal passage is expected through the middle of the week, leading to a renewal of strong southerly swell for the second half of the week. More on this in Friday’s update.