Pumping easterly swells for Southern NSW

Ben Matson picture
Ben Matson (thermalben)

Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Wednesday 8th March)

Best Days: Most days should have great waves, especially Friday and even more so Saturday. Persistent S/SE winds could create some problems north of Wollongong on Thursday, and in the Hunter on Friday. Clean easing beachies on Sunday with early light offshore winds. 

Recap: It’s been large and generally windy from the S/SE as expected. Most open south facing beaches beaches have seen sets in the 6ft range however there have been reports of up to 8ft waves at some locations (though no real discernible pattern or trend). Some beaches have seen brief pockets of SW winds but this has generally been the exception rather than the rule.

This week (Mar 9th - 10th)

No changes at all to the forecast issued Monday.

Model guidance has held this Tasman low in a slow moving position over the eastern Tasman Sea, and a further re-intensification today will generate a final pulse of E/SE for Friday

This means surf size will fall away into Thursday, but in saying that it’s still going to remain quite sizeable at first - around 5-6ft across most open beaches in the morning with perhaps a slight drop during the day

The southern flank of the Tasman Sea is expected to slow recede during Thursday, easing the pressure gradient across Southern NSW and causing winds to abate. However, most regions between Sydney and the Hunter are likely to remain under a steady S/SE airstream - but there is a better chance (than today) for a brief morning SW flow across many beaches, and the pressure gradient across the South Coast will be much weaker so conditions will be quite good south of the Illawarra.  

On Friday, we’ll see a further easing of the pressure gradient and therefore a more uniform light offshore breeze across most coasts. The only coastline of possible concern is the Hunter which may just see the outer flank of the low skirt the region, but I think it’ll see a strong improvement from previous days.

As for Friday’s swell renewal, we’re looking at a lot of size as the wavelength draws out and swell heights increase a touch. This should kick up size into the 6-8ft range at most exposed beaches, and a handful of reliable offshore bombies could even push higher than that at times (maybe some rogue ten footers?) if we're lucky.

The reason for this is that surface winds were very strong through the eastern Tasman Sea today, though not extraordinarily so - what kicks this swell potential above standard weather systems is the duration and length of the fetch - it’s rare to see the entire Tasman Sea covered with a stationary easterly fetch for this amount of time.

So when we see fetch re-intensifications of this nature, the surf potential is a little higher as the winds are acting on an already active sea state - meaning it’s not starting from a steady state, which requires more energy to create the same swell size and strength. The periods reflect the new swell quite well but the surf model isn't translating it quite as well due to the smaller swell heights (relative to today, which had a considerable windswell loading). So I have bumped up my figures from the model output. 

Sheltered locations will obviously be much smaller though.

Overall, we've got continuing large easterly swells and light offshore winds for the next few days. Pick and choose your location according to your ability - there’s gonna be a lot of water moving around so it’ll be worth watching the ocean for an extra twenty minutes before you paddle out. 

This weekend (Mar 11th - 12th)

The Tasman Low will weaken through Friday, but with a couple of days for the swell generated by Thursday’s fetch to reach the mainland, this means we’re looking at large surf to kick off the weekend

However the trend will be downwards both days; slowly at first on Saturday and then more rapidly on Sunday. Saturday should see early 6ft bombs at exposed beaches, with light offshore winds and afternoon sea breeze. By the afternoon, expect much less consistent 4-5ft sets. Expect smaller surf at southern ends.

On Sunday the early morning session should hold around 3-4ft at open beaches with an easing to 2-3ft during the day. Again, early light offshore winds - probably NW - will keep conditions smooth but we’ll see a NE breeze crop up into the afternoon.

All in all, it's looking like one of the better weekends in Southern NSW in quite a while. Certainly a good period to hit the road!

Next week (Mar 13th)

There's nothing major standing out for next week, but nevertheless we have a couple of systems to keep an eye on in Friday’s update:

1. A small trough off the SW tip of New Zealand around Sunday could supply a small SE swell mid-week.

2. A developing surface trough over the eastern states from Sunday onwards looks like it could generate building NE swells through the early to middle part of the week, though it’s a complex setup that could swing either way. 

Monday should see small leftover SE swell from the weekend but it’ll be diminishing quickly. So really, you’ll have to make the most of the next few days as the following week is a little dicey right now. 

See you Friday!


mick-free's picture
mick-free's picture
mick-free Wednesday, 8 Mar 2017 at 4:29pm

cmon hurry up with those winds its torture

dave knee's picture
dave knee's picture
dave knee Wednesday, 8 Mar 2017 at 4:30pm

Your finally able to use the word Bomb must be excited

mk1's picture
mk1's picture
mk1 Wednesday, 8 Mar 2017 at 4:36pm

Thank you Benjamin.

Westofthelake's picture
Westofthelake's picture
Westofthelake Wednesday, 8 Mar 2017 at 8:21pm

Wow about time! How many weekends over the last 4 months have Newcastle surfers been greeted by a southerly change and or a pissy little wind swell. Considering we are 4 months through the official cyclone season and not one decent low has even remotely formed in the coral sea, the odds are 'lining up (like this weekends swell) that it may be a very busy autumn indeed! After what was quite a depressing summer. this probability 'makes me very happy. Thanks Ben!

batfink's picture
batfink's picture
batfink Thursday, 9 Mar 2017 at 10:55am

Head north everyone, gonna be classic.

gunther's picture
gunther's picture
gunther Thursday, 9 Mar 2017 at 6:28pm

Head south, lighter winds and less crowded

Craig's picture
Craig's picture
Craig Thursday, 9 Mar 2017 at 7:59pm

Solid sets this afternoon!

thermalben's picture
thermalben's picture
thermalben Friday, 10 Mar 2017 at 11:35am

Highlights clip from Shark Island this morning (winds have gone southerly again so it's now quite bumpy).