Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Friday 4th January)

Best Days: Sat: peaky NE swell, with a period of good winds through the day. Tues/Wed: inconsistent long period E'ly swell and a small trade swell. Thurs/Fri: E/NE groundswell, though inconsistent. 

Recap: A steady though inconsistent E/NE swell has maintained 2ft+ sets across the coast over the last few days, whilst a small S’ly groundswell built on Thursday afternoon, pulsing to 2-3ft across exposed Sydney south facing beaches and the Hunter region before easing slowly today. Winds have been light for almost the entire period so conditions have been clean, though NE winds are now starting to freshen.

Thursday afternoon's new S'ly groundswell in Newcastle, mixing up with a peaky E/NE swell

This weekend (Jan 5 - 6)

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There’s a few minor tweaks to the weekend forecast but general things will probably pan out as per Wednesday’s notes. 

A trough will push up the Southern NSW coast on Saturday, resulting in N/NE winds tending NW, then becoming light and variable, before swinging moderate to fresh S’ly. This will be a slow moving pattern so it’s hard to be totally confident in the timing, but current expectations are a little faster than earlier model runs: a late morning arrival in the Illawarra, into Sydney early-mid afternoon, reaching the Cenny Coast and Hunter region late in the day. 

Today’s small easing south swell will be all but gone by Saturday, however we’ll see persistent small E/NE swells plus a building short range NE swell from a strengthening fetch off the coast overnight. Although there’s not a lot of wind at the coastal margin right now, we should maintain faith in the model guidance which expects a good 30kts by the early hours of Saturday morning, stretching from Port Macquarie all the way to Eden. It’s not perfectly aimed within our short range swell window so the larger set waves (3-4ft) may not have the same broad coverage we’re used to seeing in NE windswell events, though there will be options at most locations.

So, expect 2-3ft surf at most open NE facing beaches (smaller at south facing beaches, and across the northern Hunter) with rare 3-4ft sets at reliable swell magnets. 

You’ll just have to work around the winds on Saturday - the early morning N/NE flow will be mainly confined to locations north of Sydney, and we should see winds easing and tending light NW ahead of the variable period just about everywhere. The models are suggesting a temporary restrengthening NE fetch off the Hunter region late afternoon just as the change approaches but I’m not sure whether this will eventuate. Then once the southerly kicks in it’ll be southerly corners only.

The N/NE fetch will slowly retreat northwards and ease overnight, leaving us with smaller, less consistent 2ft+ leftovers for Sunday morning, becoming smaller throughout the day. However we will also see building S’ly windswells in associated with a fresh southerly breeze, with size around 2-3ft at south facing beaches. 

In fact there is a suggestion we could see a small closed low form off the Hunter coast on Sunday, which - if it eventuates - could enhance wind speeds immediately offshore and bump up the windswell estimate by a foot or two. However, if that occurs conditions won’t be great. 

So, my pick of the weekend is some time on Saturday, once the wind slackens off, with plenty of peaky NE swell at exposed beaches. 

Next week (Jan 7 onwards)

Sunday’s small closed low probably won’t amount to much so we’re not looking at any major swell sources to kick off the working week. 

That being said, even in a moderate (and weakening) state, a small near-stationary low pressure system with 20-25kts of SE breeze just off the coast could maintain 2-3ft waves at exposed beaches. I’ll rate it as a low percentage event for now, and will revise over the weekend if any further information comes to hand. 

Elsewhere, and TC Penny in the Coral Sea will remain outside of our swell window for the entire forecast period.

However, TC Mona recently developed near Fiji, and the latest model guidance now pushes it south of Fiji into our swell window. Unfortunately, despite a south-westerly track right throughout swell window - which would ordinarily be viewed positively as having excellent swell potential - a high pressure system in the Tasman Sea will create a strong ridge through the Coral Sea, causing the strongest pressure gradient to occur on its western flank, aimed away from our coast (see below). Additionally, the trailing fetch behind TC Mona doesn’t look very impressive either. 

What this means is that we’ll be relying on mainly sideband energy in Southern NSW, as the largest waves will be aimed into the Far Northern NSW and SE Qld coasts. This new swell is expected to arrive around Thursday lunchtime or afternoon, and build towards a peak on Friday morning. At this stage I think we’ll see occasional 3-4ft sets+ but I’ll revise this in more detail on Monday. There is certainly the potential for an upgrade, given the overall model trend of the last few days.

As for the first half of the week, freshening N/NE winds Tuesday will kick up some local windswell for that afternoon and early Wednesday though without any major size (2ft+).

Additionally, a powerful but very low latitude Southern Ocean low pressure system pushing south of Tasmania later this weekend will set up an inconsistent long period S’ly groundswell, arriving Tuesday and peaking later that afternoon or perhaps early Wednesday as well. Despite the small ocean swell size, the very large periods with the leading edge (18-19 seconds) should help to amplify surf size and a handful of reliable south swell magnets in Southern NSW could see 3-4ft+ sets. However this will be the exception rather than the norm. Perhaps with the secondary NE windswell in the water we'll see some lovely A-frames, as Wednesday morning looks like it'll see light winds. 

So, that’s about it - waves from just about everywhere throughout the forecast period, and plenty of good windows of opportunity.

Have a great weekend, see you Monday!