South-east Queensland and Northern NSW Surf Forecast by Ben Matson (issued Wednesday 7th September)

Best Days: Thurs/Fri/Sat: plenty of building swell (biggest Fri/Sat) but local winds may spoil the party. Sun: peaky combo of swells with better winds. 

Recap: Small combo of intermittent southerly swell and building trade swell for the last few days. 

This week (Thursday 8th - Friday 9th)

As per the gradual increase in surf size across the South-east Queensland buoy network, the expected trade swell is slowly building across the region. This upwards trend is expected to continue through Thursday and Friday across SE Qld and Far Northern NSW, reaching a peak late Friday afternoon. 

At this stage it still looks good for late 4ft sets across the Gold Coast on Friday afternoon (smaller Thursday and early Friday), reaching 4-5ft at exposed Sunshine Coast beaches. Relatively low swell periods will create smaller wave heights across the various point breaks and other sheltered spots, and surf size will also slowly taper off with increasing distance from the NSW/Qld border.

The main problem during this time frame will be the local wind. Moderate to fresh E’lies will prevail throughout Thursday, strongest across the Sunshine Coast with decreasing speeds with increasing southerly latitude. Most regions - except possibly the Sunshine Coast - should see isolated pockets of lighter SW winds around dawn though this won’t last too long.

On Friday, as the swell is building towards a peak, winds are expected to veer more north-east and this will certainly create some problems. There’s also a reduced chance of seeing isolated regions of light SW winds early morning, as the ridge will be a little closer to the mainland, and a little firmer too.

As for the remainder of Northern NSW - which will see smaller levels of building trade swell during this period - we’re looking another small pulse of long period S’ly swell building across south facing beaches on Thursday. This will have originated from the tail end of the same broad frontal progression that has generated the last few days of minor southerly swells.

However, this last fetch looks slightly better aligned - sure, the front tracked across the south-eastern Tasman Sea, outside of our swell window, and at speed too - but it displayed a slightly more meridional alignment than the previous fronts, which means it'll spread back into the coast a little better. Core winds speeds were a little stronger too (50kts) and we’re therefore expecting slightly higher peak swell periods.

That being said I don’t want to overestimate potential wave heights from this swell as it’s a flukey part of our swell window and Northern NSW will only see small levels of energy glancing the coastal margin. However, we’re seeing decent 2ft sets across south facing beaches today and this should definitely punch a little higher tomorrow. 

I think occasional 3ft sets is a reasonable call for south facing beaches on Thursday afternoon (smaller earlier, especially in the north); set waves will be rather inconsistent but all of the available data points towards some really nice straight lines across the region for the late session. Keep in mind that beaches not directly open to the south will be much smaller.

On Friday, the south swell will rapidly ease, and in addition to the building trade swell we’ll also see short range NE windswell associated with the localised N’ly fetch. Unfortunately these winds are expected to become pretty strong during the day (especially the Lower Mid North Coast, where it could reach 20-25kts) but there should be some peaky waves inside sheltered northern corners. 

On the balance though, Friday looks pretty average for much of Northern NSW due to these winds. So keep your expectations pegged appropriately low.

This weekend (Saturday 10th - Sunday 11th)

Hmmmmm. The weekend looks like a real mixed bag which is a shame as we’re looking at plenty of swell for Saturday.

A front is expected to cross the Southern NSW coast early Saturday morning, but it’s only expected to slowly influence the NSW coast up to about Port Macquarie. Winds will eventually swing W’ly then S’ly during the morning/lunchtime period but locations north of about Coffs Harbour are looking at northerly winds all day. 

Friday’s trade swell will hold into Saturday, in fact we’re looking at a combination of swell trains in the water. First up: the front responsible for Thursday’s S’ly swell will merge with a broad ridge across the Northern Tasman Sea (also during Thursday), reinforcing the back end of the fetch and supplying a small reinforcing E’ly swell for the weekend.

The trades across the southern Coral Sea will also continue to supply E/NE energy into Saturday but they’ll be weakening by this time so the trend will be downwards during the day and into Sunday. Plus there’ll be some short range NE windswell in the mix too (largest across the Mid North Coast, smallest across SE Qld). 

Estimating wave heights from all three sources is a little difficult as they’ll all influence the coast in a different way - for example, the trade swell(s) will benefit SE Qld the most, whilst the NE windswell will benefit the Mid North Coast the most. That being said, the combined size should be roughly similar across most coasts for the early session on Saturday, probably somewhere in the 3-4ft+ range at open beaches. Though with the likely northerly flow across most locations this is probably a moot point (unless you’re south of Coffs Harbour, in which case there could be some great waves at southern ends).

Sunday looks like a better proposition. A weak ridge is expected to push across the Northern NSW coast overnight Saturday, and should push moderate W’ly tending S’ly winds across the region on Sunday. Saturday’s swell combo will be easing but early Sunday morning should see 3ft+ sets across most open beaches before smaller surf settles in throughout the day (wave heights may be a little smaller across the Mid North Coast).

And just to throw another curveball into the mix - a small front exiting eastern Bass Strait on Sunday may generate a small flush of south swell for the Mid North Coast late Sunday afternoon. 

Anyway, it’s a very complex outlook for now so let’s wait and see how Friday’s model runs are looking.  

Next week (Monday 12th onwards)

Continuing strong frontal passages through the Southern Ocean and lower Tasman Sea next week will produce small to moderate long period S’ly swell for several days. No major size is expected but we can expect surf size to occasionally pulse intermittently in the 2-3ft range from Tuesday all the way through Friday. 

Also, the long range models are suggesting we’ll see an unstable troughy pattern off the South Coast early next week, which - whilst not showing any major signs just yet - could lead to the evolution of a more significant swell producing system in the Tasman Sea, around mid-week. More on this in Friday’s update.