Return swells from the south

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Ben Matson (thermalben)

Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Wednesday 14th January)

Best Days: Thurs: may see an a'noon pulse at south swell magnets. Fri: decent south swell with good winds in the morning. Sun: solid south swell but tricky winds.

Recap: Lots of great waves over the last few days with a building E/NE and NE swell, and generally good winds for the most part. Set waves have been mainly around 3ft although some bigger waves reported at swell magnets. Today in particular saw excellent conditions as winds swung NW through the morning, with great waves reported across the Northern Beaches (interestingly, a shallow sea breeze has affected the Eastern Beaches and Cronulla, but nowhere else).

This week (Jan 15 - 16)

This lovely trough responsible for our recent NE swell is moving offshore, and so the responsible fetch is tracking outside of our swell window. As such wave heights are starting to fall and will do so more rapidly overnight. We may see some small residual swell early Thursday (say, 2ft or so) but for the most part there won’t be much oomph in it. 

Meanwhile, we’ve got two pulses of return south swell, that will originate from the opposite side of the trough as it clears to the east. The first is located inside one of our funkier swell windows: a strong W/SW fetch exiting eastern Bass Strait right as we speak, whilst the standard is a more common deepening low just off the South-east coast of Tasmania (later today) which will then track rapidly SE.

The first swell is a little hard to be confident on (both size and timing), because the fetch is not aimed in a favourable part of our swell window (and the models aren’t picking up much either).

Additionally, the alignment and position of this fetch will create an “axis of refraction” along the Southern NSW coast - a point where to the south wave heights will be considerably smaller than to the north. This is likely to be in the Wollongong region - so expect very small waves all day Thursday south of here.

However, exposed south facing beaches in Sydney and especially the Hunter should see a new pulse of S’ly swell from about late morning onwards (so, expect small surf in the morning). These swell magnets may pick up some mid-afternoon waves in the 2ft to almost 3ft range (if we’re lucky). Conditions will be clean early under a light W/SW breeze but a moderate SE breeze is expected to push through for the afternoon, which may spoil conditions at exposed spots. 

The second south swell will be bigger, and should hit the South Coast late Thursday afternoon before reaching Sydney overnight. It’ll be well and truly in the water for the early session Friday with 3-4ft+ waves at south facing beaches (bigger in the Hunter), but much smaller surf elsewhere due to the acute southerly swell direction. 

Conditions are looking great for most of Friday with light variable winds ahead of a mid-late afternoon sea breeze.

It’s also worth reaffirming that we’ll also see small pulses of intermittent E/NE swell during this time (from the same distant source that’s been prevalent for the last week) but these south swells will certainly be the focus of the short term forecast period.

This weekend (Jan 17 - 19)

You'll have to get in early on Saturday. Friday’s south swell is expected to have eased significantly by this time - and will continue to drop during the day - so make the most of the dawn patrol for the tail end of this energy (again, best suited to south facing beaches). It'll be clean early with offshore winds, however a moderate S/SE change is expected through the afternoon, associated with a vigorous frontal progression tracking through the southern Tasman Sea.

These fronts will kick up a stronger south swell for Sunday that should reach 3-4ft+ at south facing beaches by the afternoon. Early wind indications are complex, due to the development of a broad, complex trough across the inland states. At this stage we’re likely to see early light variable winds tending moderate to fresh E/SE during the day but I’ll revise this in more detail on Friday.

Next week (Jan 20 onwards)

We can now safely write off the prospects of a decent E/NE or NE groundswell from the previously discussed cyclone activity in the Coral Sea.

The surf potential for early next week will initially hinge around some strong but highly refracted southerly groundswell extending from the tail end of the weekend’s frontal progression. So, south facing beaches will pick up the most size but winds are looking suss as per Sunday’s outlook.

Otherwise, we’re likely to see another mid-week short range NE windswell through Tues/Wed thanks to a developing ridge along the coast, and another strong front with an associated south swell during the second half of the week.

The models are also suggesting  some Tropical Cyclone activity in the Coral Sea mid-next week, which could lead to a possible NE groundswell event later next week or the following weekend - but this is a very long time away and I’m not getting my hopes up for this for a few days yet. See you Friday!