Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Monday 15th May)

Best Days: Wed: fun, easing S/SE swell with improving winds. Thurs: small but clean early. Mon: decent long period S/SE groundswell, winds unsure though. 

Recap: Small E’ly swells faded over the weekend but remained just big enough for some rideable waves. We’ve seen a minor increase in size today thanks to a trade flow that developed off the North Coast on Sunday, however winds are freshening from the S/SW as a low develops off the Far South Coast. 

Inconsistent E/NE swell at Manly this afternoon

This week (May 16 - 19)

My hopes for a decent pulse from this developing Tasman Low have been dashed. 

Whilst the low will become larger and stronger than model guidance indicated on Sunday (as anticipated), its strongest winds are expected to develop on the low's northern flank, aimed towards New Zealand’s North Island and the South Pacific.

A reasonable NE fetch developed along the troughy infeed through the Central Tasman Sea yesterday, but this fetch has moved too fast southwards to benefit swell production for Southern NSW (the Far South Coast will see the most size; Tasmania’s East Coast will be the biggest beneficiary - but ultimately there won't be much in it). 

The southerly fetch currently developing adjacent the South Coast will produce some small to moderate short range S’ly swells on Tuesday (peaking around 3-4ft at south facing beaches), easing slowly from Wednesday, before residual S/SE energy pads out the rest of the week, originating from the latter stages of this low as it tracks towards the SW tip of New Zealand’s South Island.

On paper, this week's synoptics look much more favourable - had you been staring at the MSLP charts in the Sydney Morning Herald (circa ’95), it’d be expected that we’d see a quality run of large SE groundswell for much of the week thanks to a slow moving low positioned in the Tasman Sea as such. But the reality this time ‘round is that all of the steering mechanisms are in the wrong spot for this low, and the strongest pressure gradients are on the wrong flanks. 

The end result will produce mainly small surf, of which we’ll have to wait for the local winds to cooperate (Wednesday, early Thursday) to see anything worthwhile. Wednesday morning is the pick of the short term forecast period with south facing beaches likely to see early 3-4ft sets (smaller elsewhere), easing during the day.

Prior to this, Tuesday's mix of small E'ly swell (2ft+) and building S'ly swell will be accompanied by fresh, gusty SW winds at times.

Otherwise, Friday looks like a generally poor day to finish the week at this stage, with a deepening trough across the inland states expected to see freshening NE winds across the coast. We’ll eventually see a building local swell but with no great quality.

This weekend (May 20 - 21)

A tricky weekend is ahead of us, and it’s likely that we won’t see much in the way of quality surf. 

The deepening trough is expected to become quite complex, with two areas of strengthening interest - one in the Coral Sea and the other around Bass Strait.

Between these two areas of development - i.e. across the Sydney, Hunter and Illawarra coasts - winds will remain NE but at only moderate strength; enough to thwart local conditions but not enough to generate any decent surf. Neither region of interest (Coral Sea or Bass Strait) look like they'll develop favourably for our region either.

We do have an interesting south swell on the way though, generated by a polar low that’s expected to push underneath Tasmania Wednesday and track towards New Zealand, eventually merging with this week’s Tasman Low. At this stage it looks like it won’t be especially well lined up in our swell window, so we’l be relying on long swell periods to compensate for the poor alignment. 

Set waves should reach 2-3ft+ at south facing beaches (on Saturday) and under the NE flow there should be a few workable option.. but not many. This swell will then ease into Sunday.

Next week (May 22 onwards)

This weekend’s merging systems near New Zealand’s South Island are expected to extend a broad fetch of southerly gales down to the Ice Shelf.

This should generate a good quality long period S/SE swell for Monday, and wave heights could push 3-4ft at exposed spots later in the day. Our model is picking up the periods nicely but doesn’t have much in the way of swell size (which I think is erroneous), so the corresponding surf size is disproportionately small. Let’s revise on Wednesday to see if the models have adjusted. 

Otherwise, the complex troughy pattern across the eastern states will likely spawn a swell generating system in the Tasman Sea at some stage next week, though there’s not much agreement in the models so we’ll need a few more days to build any level of confidence.