Small swells until Sunday; possible large clean SE swell Tuesday

Ben Matson picture
Ben Matson (thermalben)

Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Wednesday 19th October)

Best Days: Sat: outside chance for a small easing NE swell with a brief window of good winds. Tues: large clean SE groundswell

Recap: Tuesday delivered a small, unexpected pulse of short range south swell, originating from one of my favourite flukey swell windows - the waters of eastern Bass Strait (and the adjoining south-western Tasman Sea). A modest front pushed through Monday afternoon, briefly displaying a 20kt W’ly fetch that - at the time, and to be honest, even now with the benefit of hindcasting tools - looked too weak and unfavourably aligned to produce any surf for Southern NSW. But alas, it did - and south facing beaches picked up occasional fun 2ft sets. This south swell eased overnight, creating very small conditions this morning, but a small new S’ly swell is building across south facing beaches this afternoon with sets around 1-2ft. Early light winds have swung to a moderate onshore so conditions aren’t great.

This week (Oct 20th - Oct 21st)

No great surf is expected to finish the week

We have two new sources of energy on the cards - a small south swell through Thursday, originating from a broad but ultimately weak and poorly aligned front pushing below the southern Tasman Sea today. I’m not expecting much size from this source but sets of 2ft at south facing beaches are possible.

Early light winds will freshen from the N/NE during the day so conditions won’t be great, the swell period will be rather low so the surf won’t have much strength. It’s really only worth considering if you’re totally desperate.

This south swell will ease back into Friday, but Thursday’s freshening N/NE winds will also kick up a small NE windswell for Friday that should produce a few small peaky waves at north facing beaches. Again, we’re not looking at very much size - perhaps a few 2ft sets if we’re lucky - and local winds will remain out of the northern quadrant so conditions are unlikely to be very good. Keep your expectations low.

This weekend (Oct 22nd - Oct 23rd)

The latest model guidance has eased back the strength of Friday’s winds, so I’m pulling back my size estimates for Saturday to around 2ft at north facing beaches, maybe a few stray bigger sets if we’re really lucky.

Conditions look tricky on Saturday as a shallow southerly change will drive fresh southerly winds across the region during the day. But, it’s not a particularly strong change and the timing is likely to move around from current expectations - which is for an arrival in Sydney mid-morning (following a period of W’ly winds early). The South Coast will see this change earlier; the Hunter a little later. But it's a moot point with not much size on the cards. 

Our surf model is also estimating a solid increase in short range swell in the afternoon, behind the change, but I think this is an overcall right now - let’s wait and see how Friday’s model runs hold out. In any case, the afternoon swell increase (if it did eventuate) would be accompanied by poor conditions. 

These low quality conditions are unlikely to improve much into Sunday under a persistent southerly flow (maybe SW for a brief period in a few local areas, such as the Northern Beaches). This will be associated with a developing multi-centered low pressure system in the Tasman Sea, which has excellent swell potential for early next week.

Most of Sunday’s increase - which could push anywhere between 4ft and maybe even 6ft at south facing beaches - will be generated by local southerly winds just off the coast, which will limit the quality of the swell, and also produce choppy conditions at exposed locations. Beaches not open to the south will be much smaller but under this wind regime they’ll be your only option. 

Let’s wait and see how things are stacking up on Friday.

Next week (Oct 24th onwards)

Sunday’s Tasman low is now modelled to intensify off the SW tip of New Zealand’s South Island during the day, before slingshotting around to the north-west for a brief period into the evening.

The models have this as a very significant system with core winds in excess of 50kts which could deliver swell periods in the 16-17 second range (which is slightly capped for this wind speed, owing to the relatively short travel duration). The slight NW slingshot could also act as a captured fetch, further enhancing swell heights and periods aimed in our general direction.

In any case, and even with some future tweaking by the swell models over the coming days, this event should set up a solid SE groundswell for Southern NSW.

At this stage, we’ll see temporarily easing S’ly windswell on Monday (down from whatever heights are reached Sunday) with early SW winds tending S'ly during the day, probably of moderate strength. The new SE swell is then expected to reach the South Coast very late Monday afternoon - possibly too late to be of any benefit to surfers (though, we’ll update the timing on Friday). 

Tuesday is therefore on track for a solid SE groundswell around 5-6ft+ at most open beaches, and possibly some much bigger waves at well-focused offshore reefs, owing to the likely long swell period. Conditions look nice and clean with light offshore winds at this stage, let’s hope the models don’t move around too much on this event as it’s one of the best looking synoptic charts we’ve had in many months.

Looking further ahead and following Tuesday’s swell we’re looking steadily easing surf on Wednesday ahead of a period of small surf through the second half of next week

See you on Friday! 


thermalben's picture
thermalben's picture
thermalben Thursday, 20 Oct 2016 at 1:35pm

Plenty of small southerly lines across the coast, shame about the 15-20kt NE breeze though.