Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Friday 10th July)

Best Days:  Late Mon (more likely Tues) thru' Fri: strong, pulsey series of south swells with good winds

Recap: It’s been a great finish to the week with a persistent south swell maintaining 3-4ft surf across south facing beaches through Thursday and early this morning, although we’ve seen a steady drop in wave heights today, and conditions have been clean with light offshore winds.

This weekend (July 11 - 12)

No change to the weekend outlook - today’s existing south swell will continue to taper off overnight and into Saturday, with very small conditions expected, even at exposed south facing beaches.

Winds will freshen from the NW all day so conditions will be clean but I’m not expecting much more than 1ft to very occasionally 2ft at most of Sydney’s south facing beaches in the morning, perhaps a few bigger sets early morning across the Hunter. Surf size will continue to ease throughout the day though so you'll need to surf early.

A developing northerly flow well off the coast today looks like it’ll eventually get quite strong (by Sunday) but it’s expected to remain focused well away from our coast. So, although we may see a small spread of weak windswell at times over the weekend (more so Sunday than Saturday), I’d be surprised to see much more than a foot at exposed beaches. In fact it will probably be tiny to flat at many locations through Sunday as the south swell dries up. Winds will strengthen from the west as a vigorous front crosses the coast; we’ll see very strong gusts throughout the day too.

Next week (July 13 onwards)

We’ve got a very complex period ahead, and to be honest I’m still not especially confident on the surf outlook for early next week. 

As we’ve been discussing for some time, a significant low pressure system is expected to form off the Far South NSW Coast on Sunday. At this stage it still looks like being a Tasman Low, and not an East Coast Low, due to several characteristics (low rainfall progs, and the low’s modelled eastward track) however these are somewhat moot points compared to the surf outlook.

In Wednesday’s notes I detailed some concerns that approaching polar fronts would become absorbed into the Tasman Low, maintaining a strong westerly component across the broader airflow around the system. This suggestion has firmed up in recent model runs, and is now even affecting Monday’s potential (as well as our mid-week possibilities). 

As per the animated image to the right (eight 6-hourly time steps from Sunday evening to Tuesday morning, courtesy of the GFS model), you can see that initially the developing low remains too close to the mainland. As such the southerly gales strengthening around the western flank of the low are at first, still positioned inside Bass Strait. 

In this model run, we eventually see a thin fetch of SW gales across the coast - this is during Monday - ahead of a broader W/SW thru’ SW fetch extending east of Bass Strait overnight into Tuesday. However, for the most part the fetch is aimed well and truly away from the coast, which means we’ll only see sideband energy across the NSW coast.

Now, the sheer strength of the system and its close proximity to the mainland will somewhat override the directional deficiencies, ensuring we see a reasonably solid south swell. However it’ll probably be about half the size (if not less) than that of a well aligned south or south-easterly fetch. 

One other point that needs to be said: the other atmospheric models are not quite in agreeance with the finer points of this (yet to develop) system, so due to the complex nature and its close proximity, some elasticity in the timing and numbers would be greatly appreciated.

So, on to the specifics -  I think we’ll see tiny conditions for most of Monday with westerly gales across the coast. As the SW fetch drops off the coast during the day, an increase is likely very late afternoon, and I feel our surf model’s estimation of 3-4ft by the end of the day is reasonable. But based on the latest data I'd be surprised if we saw much new (small) energy before mid-afternoon, with the biggest waves showing on dark. So, keep your expectations low.

With the Tasman Low remaining slow moving through the Tasman Sea for a few days we’ll then see a pulsey series of refracted southerly swells through Tuesday, and possibly early Wednesday (3-5ft south facing beaches), with rapidly easing W/SW winds. The Hunter almost always does really well out of these systems so easy 6ft+ surf is possible at the swell magnets at times through Tues/Wed (owing mainly due to the strong swell periods associated with very strong core winds exiting eastern Bass Strait). But, beaches not open to the south will be much smaller. As a reference point, this is expected to be more greatly exaggerated than this week's south swell, which had a broader spread and was more S'ly than SW in direction.

As for the second half of the week, it’s hard to have confidence but right now it seems that the low will remain in our southern swell window through Wednesday and Thursday, which suggests some form of reasonably strong (if only moderately sized) south swell up until Friday or Saturday, probably somewhere between 3ft and possibly 5ft at south swell magnets if we're lucky. 

And one final other possible swell source - N/NE gales in the central Tasman Sea from Sunday thru’ Tuesday are rather poorly aligned for the coast, and they also track unfavourably to the east - but they still can’t be ruled out as a possible source of small NE swell, probably just for the South Coast though (I doubt we'll see anything across Sydney, Hunter and Illawarra coasts).

I wouldn’t put a recommendation on any quality surf originating from this system but that being said, I also wouldn’t be surprised if we saw around 2-3ft of peaky surf (give or take) at NE swell magnets through the first half of next week. 

So there ya go - after a great week of steady south swell, it looks like we’ve got another week ahead with more of the same. That’s winter in Sydney! See you Monday.