Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Wednesday 21st November)

Best Days: Thurs: fun SE swell with offshore winds. Fri: easing SE swell with offshore winds. Chance for a very late [pulse of new S'ly swell. Sat/Sun: solid S'ly swell, mainly W/SW winds, tending S'ly at some point on Sun. Mon/Tues/Wed: small SE swells. Thurs onwards: more S'ly swell.

Recap: Monday's E/NE swell eased through Tuesday though managed to punch higher than expected early morning with a few 2-3ft sets, before becoming smaller into the afternoon. The morning also offered clean conditions ahead of freshening NE winds into the afternoon. Today’s seen a combo of NE windswell and building SE swell, of which the latter was detected as ‘peak energy’ at the Sydney buoy around 11am - though there was SE energy visible late yesterday and early this morning, which was likely lower strength swells from an earlier incarnation of the responsible system. We’re now seeing strong 3ft sets out of the SE across most beaches, and it’s still yet to reach a peak - model guidance anticipates this will occur around lunchtime tomorrow. Winds have been quite mixed across the coast: Newcastle has been NW all day, with gusts reaching 34kts in the early afternoon, but we’ve seen light to moderate N’lies or variable winds elsewhere. The Illawarra went moderate E’ly for a period around lunchtime, following NW winds gusting 32kts at Bellambi around 5:30am. So in summary - no discernible wind trend across the region, which is a bugger to forecast!

This week (Nov 22 - 23)

Today’s Forecaster Notes are brought to you by Rip Curl

Satellite data over the last few days has showed our fetch off New Zealand’s South Island - responsible for today’s new SE swell - to be quite strong, and holding within our swell window for a reasonable length of time. Therefore, I’m going to marginally upgrade the outlook for Thursday from 3ft+ to 3-4ft. Bigger sets are possible across the Hunter region, though they'll be inconsistent at times.

Even better, with a fresh surface low developing east of Tasmania on Thursday, we’re looking at freshening NW tending W/NW winds so all beaches will be super clean. It’ll be well worth coordinating some water time.

Our SE swell will then slowly fade through Friday, initially some inconsistent leftover 2-3ft sets at exposed beaches but easing to 1-2ft throughout the day. Conditions will remain clean with fresh offshore winds out of the west.

However there’s still more potential action in store for the rest of the day. 

The low forming east of Tasmania on Thursday is expected to deepen rapidly, displaying storm force W’ly winds across eastern Bass Strait and the Far Southern NSW Coast into the early hours of Friday morning (we’ll experience a milder version of these winds across Sydney, Hunter and Illawarra coasts).

The precise surf outlook is very hard to be confident in - even at just 48 hours out - because the low will sit right on the periphery of two flukey swell windows, and small model aberrations over the next few days could deliver wild swings in the surf potential.

See below for a cross-section snapshot between the ECMWF (left) and GFS (right) models, for early Friday morning. The size, strength and orientation of the fetch exiting eastern Bass Strait is different between each model, and ECMWF has a thin secondary fetch of southerly winds adjacent the Tasmanian East Coast up to Flinders Island, whereas GFS doesn’t. 

Plotting a line-of-best-fit between the models doesn’t improve things either as they’re both acute swell sources as it is. 

Regardless, I’ve gotta make a call on this source for Friday, and it is: no new southerly swell across Sydney, Hunter and Illawarra coasts until mid-afternoon at the earliest, by which time reliable south swell magnets should start to slowly see some new energy glancing the coast. 

The extreme southerly direction will create a very wide range in size, with the major of beaches completely missing out, but south facing beaches should pick up 2-3ft+ sets in the few hours before dark, and Newcastle should push a little higher (3-4ft+).

However, there’s not enough confidence in the swell source (or even the timing of the energy, if it does eventuate) to work around - allowing a couple of hours elasticity on the arrival time could push back the first signs of this swell to dusk, or later - and an overnight swell event is of zero value to us.

Additionally (and unfortunately), because of the way these swells spread back into the mainland from the source exiting eastern Bass Strait, there won’t be any way to efficiently ‘track’ it moving up the South Coast either (i.e. giving us a few hours heads up). So all we can do is sit back and wait for the ASCAT passes to confirm the fetch - they're due around lunchtime - and then monitor the surfcams for signs of life. 

I’ll update in the comments below tomorrow as more information comes to hand, so that we can pin down things a little more precisely. Or at least have a little more confidence in the chance for a late round of fresh south swell. 

This weekend (Nov 24 - 25)

With Friday’s late south swell being a rather complex event, the weekend isn’t any easier to digest either. The Tasman Low is expected to meander in our swell window throughout the weekend, displaying varying degrees of strength and thus a lot of sizeable south swell potential for Southern NSW.

Rather than waffle on any more in these notes debating the intricacies of each model run, there’s still one more forecast day between now and the weekend - so I’ll leave that opportunity until Friday.

As such, right now there’s no change from Monday’s notes, with both days still exhibiting potential for a solid S’ly groundswell in the 4-6ft range at south facing beaches (smaller elsewhere) with W/SW winds on Saturday likely to give way to a more S’ly airstream at some point on Sunday (early offshores likely though).

So, good conditions for the most part, and a strong, sizeable south swell on the cards for both days. 

More details in Friday’s notes. 

Next week (Nov 26 onwards)

As per Monday’s notes, the model guidance is suggesting we’ll see the after effects of the Tasman Low lingering through the start of next week, contributing smaller though useful SE swell to our region for a few days. However the S’ly swell from the weekend will ease rapidly through Monday.

Otherwise, we’re looking at a similar winteresque synoptic pattern mid-next week with strengthening W’ly winds and a low developing off the East Coast of Tasmania, generating fresh punchy southerly swells for the second half of the week, and maybe next weekend too.

See you Friday!