Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Monday 19th September)

Best Days: Tues: easing south swell with early offshore winds. Thurs: small late new SE swell with offshore winds. Sat/Sun: solid but easing combo of S'ly and SE swells with good winds.  

Recap: Friday’s south swell eased slowly throughout the weekend, with Saturday morning still showing 2ft+ sets across Sydney’s south facing beaches and 3-4ft sets across the Hunter. Smaller waves were reported into Sunday - mainly 1-2ft across the Sydney stretch - though there were isolated reports of bigger waves up and down the coast. Today we began with a small weak mix of trailing south swell and north-east windswell. However, the trough that pushed off the coast overnight developed a thin band of S’ly gales off the Far South Coast this morning, and this has built a new southerly groundswell across Sydney’s south facing beaches with sets now pushing the 4ft mark. Conditions are clean with mainly moderate W’ly winds. 

Strong southerly lines at Bondi this afternoon

This week (Tuesday 20th - Friday 23rd)

The trough in the southern Tasman Sea has formed a low pressure system though it's unusual in its setup and ultimately we’re probably looking at the peak of its swell potential right now.

The southerly fetch that generated today’s short range energy is already exiting our swell window to the east, and a strong easterly fetch on the southern flank of the low is aimed into eastern Bass Strait and Tasmania’s East Coast more than anywhere else. So, we may see a small level of SE swell spread up into the Illawarra/Sydney and Hunter coasts into Tuesday but there probably won’t be much in it.

Therefore Tuesday is looking at a general easing swell trend across the region. South facing beaches should see early 2-3ft sets but it’ll abate slowly during the day, probably down to 1-2ft by mid-late afternoon. Expect smaller waves at beaches not open to the south. A few bigger sets are possible around dawn but I think we’ll be close to the peak of this event later this evening and through the middle of the night. 

Keep in mind that the Hunter usually does very well out of these directional south swells so expect another foot - or more - across Newcastle beaches. 

Surface conditions are looking really good on Tuesday morning with early light offshore winds ahead of an afternoon sea breeze. 

A broad trough is then expected to develop across inland NSW coast on Wednesday, freshening northerly winds about the coast ahead of a late - possibly overnight - westerly change. Surf size will be small with mainly residual SE swell off the bottom of the Tasman trough/low.

This low is expected to stall somewhere in the vicinity of New Zealand on Tuesday and Wednesday, and a resulting ESE fetch exiting Cook Strait will generate a small swell for the middle to latter part of this week. Current guidance suggests this fetch will initially be aimed to the south of our region, and then finally when it does swing clockwise (in our favour) it’ll be weakening. So, surf prospects are not high at this point in time; we may see a few stray 2ft sets later Thursday and into Friday. I’ll revise this outlook on Wednesday.

Otherwise, the inland trough pushing off the coast later Wednesday and into Thursday doesn’t look too dissimilar to yesterday’s system. We should see a return southerly fetch develop in a thin strip off the Far South Coast overnight Thursday, resulting in a punchy short range south swell for Friday.

At this stage it looks like there’ll be a little more wind from a less favourable direction this time ‘round (fresh and gusty S/SW tending S’lies) but there shouldn’t be any shortage of size; early indications are for 4-5ft sets at south facing beaches (smaller elsewhere, but bigger in the Hunter). Let’s recalibrate this on Wednesday. 

This weekend (Saturday 24th - Sunday 25th)

Friday’s trough will probably form a broad Tasman Low to finish the week but this system is expected to produce a peak in swell before we kick off the weekend.

As such, it's looking like Saturday will see an initially strong combination of easing S’ly swell and small underlying SE swell (spreading from the bottom of the slowly-eastward moving low), with surf size then declining into the afternoon and further into Sunday. We should kick off with 4ft sets at south facing beaches (a little bigger in the Hunter, but much smaller elsewhere) but by Sunday it’ll be down to 2ft+ across open beaches with likely a greater percentage of SE swell in the mix. Expect slightly bigger waves across the South and Far South Coasts, originating from the SE fetch, though probably no more than 2-3ft+.

All in all, not a bad weekend at this early stage.

Next week (Monday 26th onwards)

The long wave pattern is suggesting another southerly change around Monday morning, which should bring about an increase in strong south swell for a day or two. 

Also, in similarity to the current Tasman system producing an E’ly swell from its latter incarnation near New Zealand, Friday’s low should result in a similar E/SE swell for Southern NSW through Monday and Tuesday - no major size but enough to keep an eye on things over the coming days.