South-east Queensland and Northern NSW Surf Forecast by Ben Matson (issued Monday 12th August)

Best Days: Tues/Wed/Thurs: plenty of S'ly swell (and some leftover SE swell early Tues, mainly Mid North Coast), with light winds, tending N'ly Thurs. Though biggest in Northern NSW, much smaller in SE Qld. Fri: smaller out of the south, with light N'ly winds in SE Qld tending NW in Northern NSW. 

Recap: What a fascinating weekend of interesting surf. On the balance, wave heights and the overall swell trend generally came in close to expectations at many locations, though there were a few curveballs where surf size and surf quality exceeded expectations. This was because of the apparent inclusion of a rare secondary swell, that originated from gale force W’ly thru’ W/NW winds from late Friday into Saturday, generating an unusual pulse of S/SE (?) energy that spread back almost 180 degrees into the coast. This produced isolated pockets of clean 2ft sets on Saturday, reaching 4ft+ at a handful of locations on Sunday (as per the D’Bah images in the weekend’s FC notes comments). I’ve seen this synoptic pattern produce similarly flukey swells before, though there’s usually at least a degree of south in the wind field to qualify the swell spread (Friday’s model guidance didn’t suggest enough, and as I’ve been on the road for the last few days, I haven’t had time to hindcast). Gusty offshore winds made for unusually challenging conditions at those locations picking up the swell, though it was certainly clean on the surface. Anyway, in addition to all of this we saw building S’ly swells from strong fronts exiting eastern Bass Strait, and south facing beaches picked up to 4-5ft waves today. Southern NSW saw a mid-late afternoon increase in secondary SE swell to 4-6ft (from a low off NZ a few days ago, as per Friday’s notes) and this should nose into Northern NSW overnight. Also worth pointing out D'Bah's incredible magnetic properties over trhe last few days, producing lovely 3-5ft waves (see image below from noon today) whilst around the corner, the Superbank has been tiny to flat. Quite incredible, really.

Lunchtime Monday at D'Bah, on point

This week (August 13 - 16)

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We’re back to a more bog-standard southerly swell routine for the rest of this week. The conveyor belt of fronts responsible for our current energy are still quite active, and will remain so through Tuesday. This means we’ve got strong southerly swell through Thursday morning at least, easing thereafter.

Though, this afternoon’s new SE swell across Southern NSW (yet to arrive across Northern NSW at the time this forecast was prepared) may produce some useful swell from this quadrant on Tuesday, though more likely across the Mid North Coast than anywhere else (smaller north from Coffs).

Anyway, there’ll be a mix of mid and long period energy, sourced from a couple of strong points within what’s otherwise a broad, elongated, slow moving fetch associated with several low pressure centres and cold fronts. 

Identifying the precise swell trend over the coming days is difficult, because at any one time there’ll be a mix of swell trains in the water: the leading edge of a new swell, arriving concurrently with the plateau of an unrelated short period event, both in addition to the backside of another previous pulse. It’s possible to have some degree of confidence in the likely phase of each swell event, but not the way in which they work together to enhance (and sometimes cancel out) surf size.

So, let’s keep things broad.

Surf size should hold steady somewhere near 4-5ft at most south facing beaches south of Byron from Tuesday thru’ Thursday morning, before the easing trend kicks in into Thursday afternoon. There’ll be intermittent periods of smaller surf during these three days, but reliable south swell magnets may occasionally see larger waves north of 6ft+.

If you have to hedge your bets, we'll probably see the upper end of this size range on Tuesday, than Wednesday or Thursday. But all three days should be characterised by good southerly energy. 

Anywhere not exposed to the south will be a lot smaller, and of course this means SE Qld. We’re looking at a flush of very inconsistent energy on Tuesday around 2ft across the outer Gold Coast points and up to 3-4ft at exposed northern ends and south facing beaches, but otherwise expect smaller surf, and unfortunately the Sunshine Coast won’t see as much size as its southern brethren. 

As for conditions, a weak high pressure ridge will extend across the coast for the next few days, creating light variable winds and afternoon sea breezes. Thursday will see the wind around to the north (though without any major strength) and it may persist across SE Qld into Friday, but we’ll be at the back end of this series by then (so, make the most of Tuesday and Wednesday). 

By Friday we’ll be on a steady easing trend, with size best suited to south friendly beaches south of the border, accompanied by light winds. 

This weekend (August 17 - 18)

Looks like a small weekend of surf ahead.

A minor front/low combo will track south of Tasmania on Thursday, and this looks to be our primary source of energy. South swell magnets south of Byron may pick up the odd 2ft set but most coasts will be much smaller, and locations without good southerly exposure will be tiny to flat (hello SE Qld!).

Light winds are expected Saturday, freshening from the north on Sunday. 

Given the recent swell activity, the weekend looks like a bit of a grovel, so unless we see an upgrade by Wednesday I’d consider other activities (read: accumulate some brownie points for the next onslaught of south swell, as per below).

Next week (August 19 onwards)

The LWT is expected to re-amplify through the southern Tasman Sea early next week, leading to a renewed period of strong, sizeable southerly swell for a few days at least. Let’s take a closer look on Wednesday.