Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Monday 29th August)

Best Days: Tues: protected northern ends should see OK waves late with the arrival of a new S'ly swell. Wed: strong but very inconsistent S'ly groundswell plus a local NE windswell, best into the afternoon when winds swing NW. Thurs AM: clean leftovers from Wed (only small). Sun: large S'ly swell though winds look very dicey at the moment. 

Recap: Small easing E’ly and S’ly swells on Saturday became very small into Sunday, ahead of a late arrival of small long range S’ly swell across the South Coast into the afternoon. This south swell has provided small clean waves across south-facing beaches today, though locations not open to the south are considerably smaller.

This week (Tuesday 30th - Friday 2nd)

New long period S’ly swell is still on track for later Tuesday and Wednesday. However, as discussed on Friday, confidence is low for this event. 

The reason being is that the low pressure system responsible for the swell is (1) poorly aligned within our swell window, (2) a very large distance from the mainland, and (3) travelling quickly, perpendicular to the great circle path through our swell window.

So, despite a broad fetch of 50kt winds at the low’s core (most of which is aimed into the South Pacific rather than the Tasman Sea), the surf we see across Southern NSW will be sideband energy and is likely to be very selective in where it focuses the biggest and best waves. 

Besides low confidence in the eventual wave heights, it’s also hard to be confident in just when this swell might arrive across the coast. Swells that travel large distances from their source have large(r) error margins, and leading edges originating from embedded fetches within active sea states are often more difficult to pinpoint because the presences of pre-existing swells can make it more difficult to detect the precise phase of the swell once it makes landfall.

So, taking all of that into account, the general trend for Tuesday looks like starting small early - a similar size to today, if not a fraction smaller - ahead of an upwards trend into the afternoon (more likely later afternoon than early afternoon). Keep in mind that the further south you head, the earlier this swell will make landfall (the Far South Coast should be seeing new energy from early morning).

Freshening N/NE winds will accompany this building swell; though winds may be light N/NW early in the day.

A second, stronger pulse of southerly from this low - characterised by larger swell periods in the 16-18 second range - is then expected to push through overnight Tuesday, showing strongest across Sydney and Hunter beaches early Wednesday morning before it trends down throughout the day. Once again, set waves will be very inconsistent.

Also in the water on Wednesday will be a small peaky NE windswell, generated by Tuesday’s winds - which are expected to remain in place across the coast through Wednesday morning, before veering N’ly before lunch then NW into the afternoon and then W/NW overnight. This means it should peak throughout the afternoon. 

As for size - around the Sydney region I think there’s a reasonable chance for occasional 3ft+ sets at south facing beaches by late Tuesday (plus a small level of local NE windswell). Wednesday morning will see bigger - but very inconsistent - sets from the south, somewhere between 3ft and very occasionally 5ft (upper end of this size range more likely across the Hunter region than anywhere else), but the local NE windswell should manage 2ft+ sets throughout the day - probably reaching into the afternoon as winds swing to the north-west. However, by this time the south swell will probably be on the decline. 

So, all in all it looks like Wednesday will be your best time to surf, probably into the afternoon as this should see the best combination of (two) swells plus a better wind direction. But if you’ve got a reliable south swell magnet that is sheltered for northerly winds, the early session could provide some good waves. Once again, let me reiterate the low confidence in this southerly swell - I’m expecting many coasts to dip out in the size department, and the combination of the northerly breeze and the inconsistent set waves means many lineups will retain plenty of wobble. So don't spend too much time on the highway for this event hunting down barrels. 

After Wednesday, the rest of the week looks rather nondescript with steadily easing swells from all quadrants and generally light variable winds as an unstable troughy pattern develops across the region. We’ll be back to the swell magnets for anything rideable during this timeframe but at least local conditions should be generally favourable.

This weekend (Saturday 3rd - Sunday 4th)

The synoptics look particularly active for the weekend.

A deep inland trough is expected to slide south-east, reforming over the southern Tasman Sea as a large Tasman low pressure system at some point on Saturday, and we’re looking at two swells from it. Initially we'll see a short range N’ly swell (Sat) as the trough draws near the coast, and then a very large S’ly swell (Sun) as the low pushes east into the Tasman Sea, driving southerly gales about Southern NSW.

Winds are likely to be an issue at many locations as the low takes shape on Sunday though, especially south from Sydney. 

It’s too early to pin down size/timing/quality expectations, mainly due to the close proximity of this system to the mainland, but either way it’s looking like there’ll be no shortage of energy this weekend. More on this in Wednesday’s update.

Next week (Monday 5th onwards)

Sunday’s Tasman low will be the dominant weather system for a day or two, so early next week looks like it’ll be influenced by leftover south swell as a minimum. There are no other systems on the long range charts at the moment, so we’ll be able to hone in on the specifics of this event over the coming days.