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

Features of the Forecast (tl;dr)

• Small, residual, inconsistent E'ly swell over the weekend with tricky winds
• Slowly building S'ly swells from Sat onwards, best suited to Northern NSW
• Large S'ly swells peaking Wed (much smaller in SE Qld)
• Strong though easing S/SE swells Thurs onwards (much smaller in SE Qld)

Recap: Persistent though slow peaky E’ly swells managed 2-3ft sets over the last few days. Thursday saw light morning winds and sea breezes, however winds strengthened from the NE today, rendering most coasts quite choppy. That being said, early morning offered light across most regions and fun waves for a few hours.

This weekend (Jan 16 - 17)

The long running easterly swell machine that’s provided an extended period of useful trade swells is finally drawing to a close. We’ll see residual energy over the weekend but with the main swell source located north-east of New Zealand’s North Island (and also east, inside the swell shadow), set waves will become a little smaller and increasingly inconsistent.

The reason for this upcoming southerly regime is a slow moving, amplifying node of the Long Wave Trough that will drive a series of vigorous fronts through our south swell window over the coming days, setting up an extended pulse of building southerly swells for the entire East Coast. Such patterns don’t favour SE Qld (mainly in the size department) but there will be waves at the outer points at he height of the event mid-week. 

In the short term, we’ve got a tricky weekend in the wind department.

A gusty S’ly change is due into the lower Mid North Coast around dawn on Saturday, reaching Coffs early-mid morning and then the Northern Rivers mid-late morning. The change will stall across the Gold Coast early afternoon, so we may in fact not see the wind swing to the south, across the Sunshine Coast.

Just ahead of the change, winds will become light and variable but it’ll be N’ly tending NW upstream. So, SE Qld beaches may see a brief period of northerlies but it’ll tend offshore ahead of the change. The Sunny Coast is modeled to see fresh afternoon NE breezes, so let’s see how that plays out (we could see some interesting thunderstorms at the convergence line between the Gold/Sunny Coast mid-late afternoon).  

As for surf, most locations will be relying on small, inconsistent E’ly swells on Saturday that will become quite full and fat through the high tide. Size may occaionally nudge the 2ft mark at exposed beaches, but don't get your hopes up.

The Mid North Coast will pick up a punchy short range S’ly swell from a fetch trailing he change - 3ft+ sets are possible at south facing beaches south of (about) Coffs by the end of the day but these locations will be wind affected. Elsewhere it’ll be a lot smaller. 

Most of Sunday should see light winds return across Northern NSW, though the Far North Coast, Gold Coast and maybe some parts of the Sunshine Coast will probably see fresh lingering SE winds in the wake of the change. The actual northern and southern extend of this temporary ridge is not clear so we could very well end up with light SW winds across the southern Gold Coast and northern Sunshine Coast. 

Residual S’ly swell will maintain inconsistent 3ft+ sets at south swell magnets south of Byron through the morning, with smaller surf elsewhere. I’m not expecting much surf across SE Qld beaches, just a small mix of leftover E’ly swell and minor S’ly swell - though exposed northern ends could see peaky 2ft+ sets. 

Now, the interesting (read: difficult to forecast) thing for Sunday - mainly related to Northern NSW - is that there will be several new, overlapping swell trains in the water. 

The first front in the LWT sequence will cross the Southern NSW coast overnight tonight, followed by a second front into the lower Tasman Sea Saturday afternoon and a third on Sunday afternoon. 

The initial south swell late Sat and Sun will have been generated by a local fetch developing off the Southern NSW coast tonight - north of Bass Strait - but subsequent swells will be sourced from much longer, broader fetches spanning a greater breadth of the Tasman Sea and extending much further south towards Antarctica.

The difficulty in forecasting this sequence is getting the size and timing estimates as each swell trains arrives, peaks and then recedes. For example, the initial short range energy on Saturday afternoon (and early Sunday) will be overtaken by a slightly longer period swell at some point om Sunday afternoon (as the initial swell eases), before the overtaking swell is overtaken itself by an slightly stronger source very late Sunday and into Monday.

So, at this stage Sunday’s inconsistent 3ft+ sets early morning could ease through until lunchtime, but at some point will reverse the downwards trend and then climb back up into the 3-4ft+ range (much smaller elsewhere). 

But regardless of the swell trend all day Sunday, I’m doubtful for much size from the south, north of the border. The low period and acute southerly direction isn't expected to favour many locations in SE Qld at all. 

Next week (Jan 18 onwards)

In addition to the three frontal swells sources mentioned above (the first two of which will generate weekend swell), we’ve got another two vigorous fronts early next week in the same region that’ll generate punchy south swells for the first half of the new week - that makes five south swells - plus a stationary polar low deep inside the LWT (S/SW of New Zealand) providing a sixth swell source for the East Coast. 

Model guidance has slightly tweaked the alignment of the most powerful front, that’s expected to generate the height of the activity around Wednesday (see below) - but despite a minor downgrade it’s still looking to be big at south facing beaches south of the border. The main issue I can see is that the flukier swell source means we’ll see a reduced coverage of large waves as it’ll only light up a smaller number of locations.

The main synoptic feature is a gusty S’ly change due into the Mid North Coast late Tuesday and then everywhere else on Wednesday. This will confine the best waves to sheltered points. Prior to this, we’ll see freshening N/NE winds (mainly Northern NSW) later Monday and into Tuesday. 

As for surf, Monday should see steady S’ly swells holding 3-5ft at south facing beaches south of Byron (smaller elsewhere) before a succession of longer period south swells buildthrough Wednesday. We may see a temporary dip in size between this pattern, most likely at some point on Tuesday morning. 

Otherwise, the Wednesday peak should push surf size into the 6ft+ range at south facing beaches south of Byron (maybe bigger). Surf size will be much, much smaller at beaches not open to the south. 

SE Qld should see slow 1-2ft waves Mon/Tues (occ bigger 2-3ft sets at exposed northern ends and south facing beaches) but the large south swell due around Wednesday has a good chance at pushing 2-3ft+ across the outer points, and 3-5ft at exposed northern ends - though exposed spots will be wind affected.

This LWT synoptic sequence will finish by way of a large Tasman Low setting up camp off the west coast of New Zealand’s South Island. This, along with a secondary polar low much further south, will maintain elevated S/SE swells through Thursday (4-6ft south facing beaches south of Byron), easing to 3-5ft on Friday (much smaller elsewhere).

Note: this is much larger than the model are expecting, so I’ll firm up the specifics in Monday’s notes. 

As for winds, an approaching trough will probably kick up some form of northerly across Northern NSW later Thursday and into Friday, though SE Qld though remain relatively light. In many ways, despite the easing trend, Thursday and Friday may end up offering the best quality swell energy of the whole period though we'll need local winds to play ball too.

So, we've got a week of strong southerly swell ahead, just gotta pick out the good winds!

Have a great weekend, see you Monday.