South-east Queensland and Northern NSW Surf Forecast by Ben Matson (issued Wednesday 5th February)

Best Days: Thurs: chance for S/SE winds north of about Byron with building E'ly swells. Fri/Sat: chance for pockets of light winds with building E'ly swells both days, plus a decent S'ly swell (south of Byron) on Fri. 

Recap: Tuesday started off very small, but a S’ly change spread across the coast early morning and S/SE swells built in its wake, reaching 3ft across the outer Gold Coast points by the afternoon, pushing 4ft+ at south facing beaches south of the border. Wave heights eased back to 3-4ft in Northern NSW today, with slightly smaller surf in SE Qld though the swing in the swell direction to the E/SE provided a more uniform size distribution across the region. Winds have been mainly fresh S/SE today, with pockets of early SW winds. 

Pumping D'Bah this morning

Empty Snapper for the Wednesday dawn patrol

Coffs on the pump this AM

This week (Feb 6 - 7)

Before we get on to the developments across the northern Tasman Sea, let’s quickly recap what’s coming up from the south.

A small long period S/SE swell is pushing up along the Southern NSW coast today, sourced from a polar low well S/SE of New Zealand over the weekend. This should provide inconsistent 2ft+ sets to south facing beaches south of Byron, though it's not really worth working around.

On Friday, a longer period S'ly groundswell will make landfall, originating from an impressive mid-latitude low that traversed the waters south of Tasmania a few days ago. It wasn’t perfectly aligned within our swell window, but the fetch was broad and strong, and with large swell periods (16-17 seconds) we should see some decent size across south facing beaches south of Byron, up to 3-5ft. However there’ll be little penetration of this swell into protected southern corners and north of the border. 

In any case, both days will see more dominant swells out of the east. 

Right now the synoptics have a strong, stationary high pressure system in the eastern Tasman Sea, directing a ridge through the northern Tasman. A trough is developing along the East Coast, with an initial focal point anticipated around Far Northern NSW on Thursday. 

The main problem we have for the next few days will be problematic winds. The trough will slide to the south, strengthening easterlies along its southern flank (south of the trough axis), but resulting in a more complex wind field across the coast to the north. 

The reason for this complexity is because the models are unable to resolve how far offshore the trough will push. Even at less than 24 hours out, the differences are stark (see image below): the Euopean solution has the trough adjacent the coast (resulting in E’ly winds tending NE north of the trough as it slides south), whilst GFS has a sharper surface trough some distance offshore, resulting in fresh S/SE winds north from about Yamba, likely SW in a few locations early morning. And lighter E'ly winds across the Mid North Coast.

It doesn’t get more complex that this. One model suggests rubbish surf almost everywhere, the other suggests decent surf at the outer points and other sheltered spots.

For my money, I think we’ll see a reasonable spread of S/SE winds across the Byron, Tweed and Gold Coasts, with pockets of early SW winds. However, locations further north (Sunshine Coast) and south of the trough (Yamba, then Coffs during Thursday, then Port Mac on Friday) are at greater risk of easterly winds. For the record, the BOM are going for fresh E/SE winds throughout.

Of course, these tricky coastal troughs often develop micro-scale systems adjacent the coast, resulting in periods of light winds too. And, this is certainly a possibility on both days - mainly northern regions on Thursday, spreading a little further south to the Upper Mid North Coast on Friday - though you really should keep your expectations very low, as there’s no way to have any confidence for where, when and how long it may happen (if it happens at all, that is).

As for surf, we’ll see building E’ly swells both days, generally from about 3ft to about 4ft on Thursday - though late afternoon and Friday will see larger surf size in the near vicinity of the trough axis (probably south from the Tweed Coast) where surf size could reach 5-6ft. This will be the result of a stronger fetch very close to the coast, working on the pre-existing sea state. However surf quality probably won’t be very high across those regions seeing the most size. 

This weekend (Feb 8 -9)

At this stage we can only discuss the weekend outlook with broad brushstrokes. 

The complex trough developing along the coast will influence the entire East Coast, the scale of which is certainly not a regular occurrence.

As for the general swell trend, it's expected to be pretty straightforward: up, up and then up some more.

At this stage we’re looking at the most size being generally distributed across coasts close to the trough axis, because that’s where the strongest winds will be seen. And this is expected around the Mid North Coast. Saturday should be north of 6ft+ and Sunday could be north of 8ft+, though eventual heights will come down to how the trough develops and just how much strength we see in the core fetch. 

North from the Mid North Coast, surf size will be generally smaller, building to 4-5ft on Saturday and then 6ft+ on Sunday. 

Of course, surf prospects will be heavily dependent on local winds and they’re looking like being problematic both days, though I am mildly confident that the trough will persist just far enough offshore on Saturday, to allow for lighter, more variable winds. We’ll probably see the trough cross the coast into Sunday bringing gusty E’lies to most regions.

So, pencil in Saturday at this stage, as Sunday looks to be a washout. On that note, also be mindful of significant rainfall totals during this period and the associated woofy water.

Next week (Feb 10 onwards)

One of the hardest parts of the current synoptic forecast to reconcile is its duration.

Most swell events last for a day, maybe two, and in rare circumstances we’ll see a sustained pattern deliver three days of waves from the same source. 

But current projections are that this trough will dominate the coastal margin for at least the first half of next week, and possibly the second half (though as a closed system east of Bass Strait - see below - delivering SE swells across Southern NSW). This means potentially seven or eight days of waves from a single, quasi-stationary source. 

And incredibly, the longer term outlook beyond this is spinning up more powerful systems in our NE swell window.

Unfortunately, the first few days of next week looks like they’ll retain some, if not all of Sunday’s airstream characteristics. That is: fresh, gusty onshore, and with a lot of rain. 

Wave heights should reach a peak early next week too.

In Monday’s notes I reference potential 10ft+ sets for Southern NSW, and I’ve got no evidence that suggests that number should be revised down. Hell, if anything there’s a chance for even bigger waves, but this will be wholly dependent on just how intense the trough becomes, and whether we see an embedded East Coast Low or not (a more likely scenario is an Easterly Trough Low, but that’s splitting hairs - the end result along the coastal strip will be very similar).

But across Northern NSW we’ll be looking at less size. Let’s ballpark Monday’s peak somewhere around the 8ft range across the Mid North Coast, 6-8ft across Far Northern NSW and then 5-6ft across SE Qld. However conditions don’t look particularly favourable under the gusty E’ly flow. 

Aside from the large peak early next week, I can’t see residual swell dropping below 4-5ft for the rest of the week and the model suggestions for two (!) tropical cyclones in and around New Caledonia (see below) suggests this could be one of the most sustained E/NE quadrant swell events we will have seen in a very long time with solid surf persisting through the following week. Of course, surf quality doesn’t look to be anything to write home about.

Just one final point - these kinds of patterns are particularly damaging to the shoreline structure and vulnerable stretches (Old Bar, Belongil etc) could take quite a battering.

See you Friday!