Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Monday 30th December)

Best Days: Most days will have fun surf, Tues will be wind affected otherwise expect workable conditions. 

Recap: Average conditions all weekend, with a peaky mix of swells (mainly NE) with 2-3ft sets on offer. We’re seeing a little more size today as size increases to 3-4ft, and winds are temporarily lighter N’ly ahead of a restrengthening NE trend.

This week (Dec 31 - Jan 3)

The current short range NE swell will continue to build in size over the coming days, and with model guidance slightly increasing wind speeds within the fetch just off the coast (see below), I have bumped up projected wave heights for Tuesday.

A southerly change will push up the coast during the day but it’s unlikely to reach Sydney until about dinnertime. At this stage, we’ll see it into Ulladulla early afternoon, and Wollongong late afternoon - so the South Coast should see a period of slack winds ahead of the change. Elsewhere, expect fresh and gusty N/NE winds. Surf size should reach 4-5ft at reliable NE facing beaches, though it’ll be smaller at south facing beaches, and across the northern Hunter.

This swell source will slowly recede during the afternoon so surf size will then ease through Wednesday. Early morning could still see occasional 3-4ft sets at NE facing beaches, but the likely trend will be down to 2-3ft. With moderate southerly winds across most coasts there’l be good options at southern ends. 

At the same time as this local NE swell starts to fade, we’ll see a building E/NE swell become more dominant, generated by TC Sarai, currently Cat 2, positioned just south of Fiji.

As per last week’s notes, it’s a poorly aligned but slow moving cyclone and I am still of the opinion that there are more positives than negatives associated with this event. The strongest flank of the cyclone is aimed towards Vanuatu, but there’s still a reasonable E’ly fetch on its southern side that's moved very little over the last few days (with a similar forecast through the middle of this week).

We’re likely to see swell energy pulse intermittently from this source over the next four or five days, with the biggest time frames being later Tuesday and early Wednesday (note: it’ll be competing with the local NE windswell at this time), and then again at some point on Thursday. Our model still isn’t really liking this system but I’m going to hold steady with my expectation that we’ll see occasional 4-5ft sets at exposed beaches. But keep in mind, this certainly won’t be four days of balls-to-the-wall cyclone swell: my size estimates are for the peak energy, at a couple of points during the week. So, expect smaller surf either side of this. And it'll be very inconsistent too, thanks to the large travel distance.

As for local conditions, we’ve got a lingering troughy pattern across the coast that’ll alternate winds between light and variable and light to moderate onshore on Thursday and early Friday, ahead of a late freshening trend from the NE Friday afternoon. 

This weekend (Jan 4-5)

A deepening coastal trough will strengthen N/NE winds across the coast on Saturday, rebuilding NE windswells into the 3-4ft range ahead of a S’ly change on Sunday, plus a decrease in NE windswell and a rise in S’ly swell from several sources, related to a complex mid-latitude low concurrently bombing below Tasmania. 

The groundswell from the parent low will only just glance our region from very late Sunday onwards (though we need to check this again on Wednesday, as it’s an impressive looking system, unfortunately poorly aligned) but at this stage local S’ly windswell should kick up size into the 2-3ft mark at south facing beaches. 

There’ll also be an undercurrent of small leftover cyclone swell all weekend too. 

So, in short: plenty of waves but with average conditions.

Next week (Jan 6 onwards)

The mid-latitude Southern Ocean low mentioned above looks amazing on the synoptics, and although poorly aligned for our region, should provide a small S/SE swell spread back along the Southern NSW coast into Monday. Let’s peg size around the 2-3ft mark for now. 

Otherwise, lingering troughiness across the coast has potential for another local system to develop in the Tasman Sea next week, though there's no clear indication of how that may eventuate. In any case, there’s not shortage of surf ahead. 

See you Wednesday!