South-east Queensland and Northern NSW Surf Forecast by Ben Matson (issued Monday 15th May)

Best Days: Tues: easing E'ly and a small possible S'ly swell, with good winds. Wed: Easing S'ly swell in Northern NSW with light winds. Only small in SE Qld. Thurs: small S'ly swell in Northern NSW with light winds. Only small in SE Qld. Sat/Sun/Mon: building E'ly swells with good waves on the protected SE Qld points. Long period S'ly swell in the water in Northern NSW Sat and also later Mon and Tues. 

Recap: There’s been plenty of east swell over the last few days; size eased slowly into Saturday before rebuilding into Sunday and then slowly easing again today. Though we’re still seeing plenty of nice lines across the coast (check this still from our Byron surfcam a short time ago, late Monday afternoon). 

This week (May 16 - 19)

The fetch that generated yesterday’s and today’s swell is related to a broad trough through the Tasman which is now consolidating into a Tasman Low east of the Southern NSW coast. 

As such, this E'ly fetch is rotating anti-clockwise away from our swell window, which means we’re looking at easing swells over the coming days.

Very early Tuesday morning may see some lingering 2-3ft sets across exposed beaches but it’ll likely become smaller throughout the morning and further into the afternoon. Expect surf size to tail off more rapidly across northern locations (i.e. Sunshine Coast) - by contrast, the Mid North Coast may retain a reasonable degree of size into the afternoon as the fetch will have spent a little more time in its swell window. 

There’s also another interesting swell source for Tuesday. As the low develops in the southern Tasman Sea, strong SW winds will extend across its northwest flank (i.e. from Southern NSW out into the northern/central Tasman). Although poorly aligned for our coast, we have on occasion seen small southerly swells spread back into the mainland from these kinds of setups.

Our model is picking up 3ft across south facing beaches of the Mid North Coast from this source on Tuesday, and it’s plausible late afternoon or even early Wednesday morning could see some small southerly lines at south swell magnets north of the border. However it’s a tricky source - most of the unusual surf we see from these events are associated with surface winds of 40kts or more, which is unlikely this time ‘round - so I wouldn’t get your hopes up (beaches not facing south will be very, very small too).

Otherwise, the Tasman Low will be a bit of a fizzer for Northern NSW (and especially SE Qld). On paper, this week's synoptics look much more favourable - had you been staring at the MSLP charts in the Sydney Morning Herald (circa ’95), it’d be expected that we’d see a quality run of large SE groundswell for much of the week thanks to a slow moving low positioned in the Tasman Sea as such. But the reality this time ‘round is that all of the steering mechanisms are in the wrong spot for this low, and the strongest pressure gradients are on the wrong flanks. 

As such, following a peak in south swell early Wednesday, the rest of the week will see small residual S/SE swell from the latter stages of the Tasman Low as it tracks close to New Zealand’s South Island. South facing beaches south of Byron may see 2ft+ sets, and elsewhere we’re looking at a slow mix of swells (including some residual E’ly swell) around 1-2ft. 

Friday looks pretty ordinary just about everywhere, with a deepening trough across the inland states expected to see freshening E’ly winds about most coasts. We’ll eventually see a building local swell but with no great quality is expected initially.

This weekend (May 20 - 21)

The models are suggesting a late season tropical low will form in the Coral Sea this weekend. This holds good potential for a building E’ly swell across SE Qld coasts, with the biggest waves likely on the Sunshine Coast (3-5ft) by Sunday and slowly easing size south from here. Expect smaller waves prior to this.

Winds won’t be great either day, but there should be some fun runners down the points. 

We also have an interesting south swell on the way for Northern NSW on Saturday, generated by a polar low that’s expected to push underneath Tasmania Wednesday and track towards New Zealand, eventually merging with this week’s Tasman Low. At this stage it looks like it won’t be especially well lined up in our swell window, so we’l be relying on long swell periods to compensate for the poor alignment. Set waves should reach 3ft+ at south facing beaches south of Byron. Let’s take a closer look at this on Wednesday.

Next week (May 22 onwards)

This weekend’s merging systems near New Zealand’s South Island are expected to extend a broad fetch of southerly gales down to the Ice Shelf.

This should generate a good quality long period S/SE swell across Northern NSW for Monday afternoon, and wave heights could push 3-5ft at exposed spots later in the day and into Tuesday. Even SE Qld may pick up some small waves form this system due to the unusual long range SE source,which is a l;ittle better located inside our swlel window though over a very long distance. 

Our model is picking up the periods nicely but doesn’t have much in the way of swell size (which I think is erroneous), so the corresponding surf size is disproportionately small. Let’s revise on Wednesday to see if the models have adjusted. 

Otherwise, the complex troughy pattern across the eastern states is likely to continue to remain a swell generating feature through the first half of next week, though there’s not much agreement in the models so we’ll need a few more days to build any level of confidence in the likely size and conditions.