Sydney Hunter Illawarra Surf Forecast by Ben Matson (issued Fri 18th April)

Features of the Forecast (tl;dr)

• Large, easing surf from Sat into Sun (smaller in SE Qld), clean early with AM offshores
• Small leftovers Mon/Tues, tiny SE Qld
• Developing low off the Southern NSW coast Tues, bringing a punchy local swell Wed - but prob just Northern NSW (biggest MNC), and with likely onshore winds
• New S'ly swell next weekend

Recap

Freshening SW tending S’ly winds on Thursday favoured the regional points with a steady trade swell holding 4ft across most coasts. Today’s seen another XL event across the New South Wales coast (reaching 15ft at some of Sydney’s offshore bombies), whilst Northern NSW saw sets around the 10ft mark, and SE Qld pushing 5-6ft. Winds have been generally favourable (moderate offshore early, tending southerly during the day) so - local sand permitting - there’s been some sizeable options around the region.

Apparently everyone's forgotton how to go left at Snapper

This weekend (Apr 19-20)

The weekend’s conditions look pretty good, with light morning offshores and afternoon sea breezes. We’re under the influence of a weak ridge of high pressure so weather conditions should remain relatively clear too. 

The large mid-latitude low in the central Tasman Sea - responsible for today’s very large surf - is slowly rotating clockwise, and by this evening won’t actually have a fetch aimed within our swell window. That being said, the sheer size and strength of the S’ly winds (on its western flank, see below) will ensure a healthy spread of energy back into the East Coast.

As for surf size, we’ve already reached the peak of this impressive event and so we’re looking at a steady drop in size both Saturday and Sunday.

However, Saturday will still kick off with relatively large surf in the 8ft range across Northern NSW (4-5ft in SE Qld, smaller running along the sheltered points), and the swell direction will edge slowly towards the SE as the day progresses, maybe even a touch of S/SE. 

Expect size to be down to around 6ft in Northern NSW by the afternoon (3-4ft exposed spots in SE Qld) with a further easing from 4-6ft to 3-4ft in Northern NSW on Sunday (2-3ft surf in SE Qld, smaller on the points). 

Keep in mind that as the swell direction tends more SE, we’ll see a slightly wider range in wave heights between exposed northern ends and sheltered southern corners.

Next week (Apr 21 onwards)

Small residual surf is expected Monday; perhaps some 2-3ft sets at NNSW swell magnets early, smaller through the day, and very small in SE Qld. By Tuesday we’ll be down to 1-2ft waves at the open beaches south of the border, smaller to the north - though conditions should be clean both days with generally light winds.

Later Tuesday and into Wednesday a weak trough off the Southern NSW coast will consolidate into a closed system. Early indications suggest it probably won't reach the threshold of an East Coast Low, but don’t be surprised if this system is upgraded over the weekend. There's a nice warm SST pool off Southern NSW at the moment (2-3 degree higher than normal) which is ideally placed to fuel a developing surface low.

However, surf prospects could be quite narrow from this source, because of the low’s close proximity to the mainland, and the likely small width of maximum fetch strength. 

Additionally, the model guidance is divergent right now (the US solution holding this low off the Hunter, whilst the European model sliding it up north), so the exact location of the largest surf could be anywhere between the Illawarra and North Coast.

Early indications are for building, potentially wind affected surf through Wednesday - mainly across the Mid North Coast, possibly extending into Far Northern NSW (though smaller in size) but with the biggest waves along the Sydney/Hunter stretch. It’s too early to have confident in size but we should see some locations up into the 6ft range, albeit chunky and bumpy.

I would however be very cautious in setting any kinds of expectations for SE Qld from this system right now. We should have a better idea in the coming days.

This system will dominate our surf outlook for the rest of the week, with the next round of energy expected to originate from a frontal system pushing across Tasmania and into the Tasman Sea around Friday, providing a fresh southerly swell for the weekend.

Have a great Easter weekend, see you Monday!