South-east Queensland and Northern NSW Surf Forecast by Ben Matson (issued Wednesday 20th January)

Features of the Forecast (tl;dr)

• Large S/SE swells throughout Northern NSW Thurs/Fri (much smaller in SE Qld)
• Generally good winds throughout - just a SE risk on the Sunny Coast Thurs, and a N'ly risk on the MNC Fri
• Fun weekend of waves though N'ly affected at times on the MNC
• Lots of tropical potential long term with building trade swells Sun onwards and a punchy E'ly groundswell mid-late next week

Recap: Well, it’s been an interesting couple of days to say the least. Tuesday offered similarly fun south swells as Monday in the 4ft range across the Mid North Coast, but much more variable results further north (and bugger all in SE Qld). A large southerly groundswell pushed up the Southern NSW coast overnight, under-performing across most regions south from the Hunter and also north from Yamba, but coming in pretty close to spec across the Mid North Coast (8-10ft sets at south swell magnets). Unfortunately, SE Qld really dipped out with outer points offering slow 1-2ft sets, and south swell magnets occasionally reached 3ft+. For the record, we’ve had intermittent reports throughout the day statewide - seemingly without any kind of obvious pattern or geographical trend - where the surf has pulsed strongly, but despite the impressive surf around Coffs Harbour (see images below), it’s fair to say that broadly speaking, we haven’t seen anything quite what was expected. Of course, the big question is why? Ususally, when hindcasting major non-events, it’s possible to see gaps in the forecast methodology, and areas where (perhaps) general assumptions glossed over important characteristics that - with 20/20 vision - resulted in an erroneous forecast. However this event is unusual, in that given the opportunity to forecast again, I probably wouldn't deviate much from the previous script. This swell was first noted in these notes nine days ago, and the models held very consistently throughout, so confidence was high - finally validated in the ASCAT satellite pass that confirmed the size and strength of the storm. However, we have a few ideas as to what went wrong - but, such analysis is better left to an individual report, which we’ll try to prepare in the coming week. 

Powerful groundswell lines in Coffs

Solid at The Pass early Wed afternoon

Small peaky overlapping swells at D'Bah

This week (Jan 21 - 22)

One of the difficulties in preparing a forecast at a time like this, is trying to seperate the events of the last 24 hours from what’s expected over the coming days.

Although we’re in the midst of a tricky, week-long cycle of solid, overlapping southerly swells, today’s under-performance doesn’t necessarily have a bearing on the swell potential from the latter stages of the same parent low, as it maintains strength off the SW tip of New Zealand’s South Island. Of course, confidence may be somewhat diminished - but we shouldn’t necessarily downgrade the next two days proportionate to what occurred (or more accurately, didn’t occur) today. 

And, as it were, Thursday and Friday were both meant to offer the better waves of this event anyway (the exact phrase in Monday’s notes was “The backside of this swell looks the pick anyway”, and last Friday’s notes said “In many ways, despite the easing trend, Thursday and Friday may end up offering the best quality swell energy of the whole period”). 

So, what can we expect?

Firstly, surface conditions will be a heck of a lot better - Thursday south from Byron, and Friday north from Byron. 

A high pressure system will move across the region on Thursday, bringing light variable winds to most of Northern NSW though a persistent ridge across the Qld coast will maintain S'ly tending SE winds here at times, mainly the Sunshine Coast.

Friday will see freshening N’ly winds across the Mid North Coast as a Tasman high strengthens a little, but there’ll be a window of light N/NW winds early morning. We’ll see a longer window of opportunity north from Coffs, and the afternoon winds shouldn’t become too strong in SE Qld. 

As for surf, we’ll see the swell direction slowly swing to the S/SE. Model guidance has an easing trend from today into tomorrow, but I'm ignoring the initial trend because the energy from the next few days will be sourced from two new regions - the migratory path of the low across the Southern Tasman Sea, as well as some sideband S/SE groundswell from the core of the low off the NZ coast today (see below). 

Although the low is now not aimed ideally within our swell window, the sheer length and breadth of the fetch - plus the strength of the core winds - should allow for 6ft+ sets at south facing beaches south of Byron throughout Thursday. Though as per usual surf size will be a lot smaller at locations not open to the south (not quite as much as straight south swells, mind). 

SE Qld should finally see better surf prospects thanks to the slight tweak in swell direction. Though, set waves will be very inconsistent, and I’m not confident for much more than a slow 2ft, maybe 2-3ft across the outer points, and long flat spells between waves (note: this isn't ideal for crowded conditions). Expect bigger 4ft+ sets at exposed northern ends and south swell magnets. Aim for the open beaches for the best options.

We usually allow 36-48 hours travel time from these kinds of systems in this neck of the woods, so given the current fetch was active as of this morning, strong sideband S/SE energy should persist into Friday morning, before wave heights start to ease into the afternoon.

Yes, this is bigger than the model is estimating, but it's a common occurrence with cut-off lows in the south-east Tasman, so I'm reasonably confident we'll see strong - though increasingly inconsistent - surf for the next two days.

This weekend (Jan 23 - 24)

There’s no change to the weekend outlook.

We’ve got a weekend of northerlies across the Mid North Coast as a trough of low pressure across Southern NSW pushes up against a Tasman high. However, these effects won’t be anywhere near as noticeable north form Byron, so expect reasonable periods of light variable winds through the mornings across SE Qld.

Saturday will see easing S/SE swells from Friday, still 3-4ft+ at south facing beaches south of Byron initially (1-2ft SE Qld outer points, 2-3ft exposed northern ends), easing through the day. Expect smaller surf at beaches not open to the south.

On Sunday, we’ll start to see a small building trade swell from a ridge developing in the lower Coral Sea from Friday onwards. This swell will become dominant next week but Sunday will start to see an uptick across SE Qld, with 2ft surf building to 2-3ft through the day. Smaller waves from this source are expected south of Byron.

However, Sunday will concurrently see some small long period S’ly groundswell, originating from a poorly aligned though otherwise impressive low southwest of Tasmania from tomorrow onwards. This is way more flukier than the source that generated today’s energy, so let’s just say this won’t be a high confidence event.

Nevertheless, this long period S’ly swell should build slowly through the day, and south facing beaches south of Byron could pick up inconsistent 3-4ft sets by close of business. Don’t expect much size elsewhere though. 

Next week (Jan 25 onwards)

The deep Southern Ocean low responsible for Sunday’s swell will migrate very slowly eastwards through our south swell window, so it’s looking like we’ll pick up fluctuating levels of small long period S’ly tending S/SE swell through the first half of next week. At this stage Monday and Tuesday could both see intermittent 3ft+ sets at south facing beaches south of Byron. 

Otherwise, the long term outlook is still looking very positive from a tropical point of view, with broadening trades through the weekend and into next week (building E’ly swells across all coasts) and the evolution of a tropical low in the central/northern Tasman Sea during the first half of next week that has the potential for a significant E’ly groundswell during the middle to latter part of next week, ballpark 4-6ft or so at exposed beaches. 

Quite a dynamic summer, eh?

See you Friday!