South-east Queensland and Northern NSW Surf Forecast by Steve Shearer (issued Mon 30th Aug)

SE Qld Forecast Summary (tl;dr)

• Small SE leftovers Tues favouring swell magnets
• Slight kick in SE/ESE swell late Wed, building Thurs
• Another extended E’ly swell event on the radar, building from Fri, solid on the weekend and into early next week, favouring Points

Northern NSW Forecast Summary (tl;dr)

• Small SE leftovers Tues favouring swell magnets, clean AM
• Slight kick in SE/ESE swell late Wed, holding Thurs with onshore winds
• Another extended E’ly swell event on the radar, building from Fri, solid on the weekend into next week, favouring Points
• Unstable, dynamic outlook for next week, stay tuned for details.

Recap

Lots of great waves over the weekend as our combination E and SSE/SE swell continued to pump under light winds in the 3-4ft range. Saturday was close to a 50/50 mix which saw heaps of great A-frame beachies and fun surf on the Points. Offshore winds from most of the morning, with NE winds in the a’noon, although some areas in NENSW maintained a synoptic offshore breeze all day. SE swell boosted wave heights in NENSW on Sunday with some strong 4-5ft sets, smaller 3ft in SEQLD, as the E swell dropped back in size and consistency.

Today has seen clean SE swell hold in the 3-4ft range in NENSW, with morning offshore winds, while SEQLD has dropped back into the 2ft range. All in all, a great run of waves.

This week (Aug 30-Sep3)

We’re in mop up mode from the great run of surf we’ve had, with surf continuing to tail off through today and tomorrow. There should still be a few 2-3ft leftovers tomorrow morning with clean conditions on offer as a shallow, troughy feature drifts off into the central Tasman, leaving a weak WNW flow that will tend N’ly through the day. By close of play leftovers will be in the 2ft range, probably worth a splash around at S facing magnets if you’ve been left shortchanged by the last swell. Small E’ly swell leftovers will pad out wave heights as well in the 2ft range.

There is a last little sting in the tail from the current low pressure system which reformed later yesterday and into today near New Zealand’s North Island and produced a short fetch out of Cook Strait. Compared to model guidance on Fri this fetch under-performed according to the latest ASCAT (satellite windspeed) pass so it’ll get a haircut in terms of expected wave heights we forecast on Friday. 

That’ll see continuing small surf Wed for most of the day - a couple of 2 ft sets if you are lucky at exposed magnets- before a small increase in ESE swell from the Cook Strait source late in the a’noon. Keep expectations pegged low, we’re only looking at 2ft+ sets. Winds don’t look great with increasing SE/ESE winds as a high pressure ridge builds in bringing an onshore flow. 

The latter half of the week sees a major pattern change, indicative of a shift towards a La Nina phase of the ENSO cycle. High pressure in the Tasman moves SE and takes up position this side of the North Island, becoming half of the “peanut” high straddling the North Island. This incredible high pressure system, 1036 and 1042 hPa, then begins to extend a long, broad fetch of SE/ESE winds adjacent to the North Island and extending through the South Pacific and into the Northern Tasman and Southern Coral Sea. This portends another extended E’ly swell event, more focussed on NENSW and SEQLD but with enough width in the fetch to ensure the entire NSW coast gets sprayed with swell from the Eastern Quadrant.

Small leftovers through Thurs, mostly from the ESE with winds beginning to tend SE/ESE as the high pressure set-up starts to ramp up.

Swell should start to build more properly through Fri. ESE swell both from the local winds in the proximate fetch and the more distant New Zealand source should see wave heights climb through Fri, from 2ft in the AM up to 3-4ft late Fri. This will come with a SE/ESE flow that doesn’t look too strong (10-15knots) but will confine clean conditions to Points. 

This weekend (Sep 4-5)

Complex weekend ahead so expect major revisions Wed if models start flip flopping. At the moment there is major divergence between leading models, mostly in respect to the local winds expected.

The short story is ESE swell from the fetch extending into the Coral Sea from the top of the North Island will be in the water both days.

Don’t get too frothed up, this is essentially a Souped up tradewind fetch, so we’re looking at size in the 3-4ft range Sat morning, muscling up into the 3-5ft range during the day as longer period swell trains start to fill in. 

Winds are a big X factor at this stage.

A trough is likely to exit the coast over the weekend, bringing a SW/S change. 

EC has this change occurring later Sat, just as the swell builds, while GFS delays the change until Sunday. 

So we could see E through NE winds Sat, or possibly a late S’ly change.

Sunday maintains this mid-period ENE swell in the 3-5ft range, with again an uncertain wind outlook, either favouring outer Points if winds tend S to SE or beachies if we have winds from the NW  to N.

I recommend revisiting this on Wed, when we hopefully have some more clarity.

Next week (Sep6) and beyond

Whoa, if complicated synoptics are your thing, next week takes some beating. 

We’ll give a broad outline today, expecting major revision due to the dynamic instability present through the Tasman and South Pacific at the moment. 

ENE swell from the New Zealand source is will continue at least through the early/middle part of next week. GFS maintains the fetch closer to the East Coast while EC sees the fetch contract NE-wards before angling into a trough/low in the eastern Tasman. Both scenarios maintain moderate ESE swell through Mon/Tues as the dominant high drifts slowly E of New Zealand.

Strong cold front and low pass to the south of Tasmania Sun/Mon 5/6Sep, bringing a strong S change potentially Mon or Tues. This generates steep rising S swell next week. A surface low may form in the Tasman during this time.

An inland low may attract a strong coastal infeed - a kind of black-nor-easter set-up- mid next week. This has uncertain surf potential depending on the position of the inland low. 

In short this is one of the most dynamic and inflammable synoptic set-ups I’ve ever seen. Anything from pumping surf to flood rain and howling onshore is on the table for next week. 

Hopefully by Wed we will be able to resolve some of the uncertainty and make some more solid calls for next week.

Check back then for a full update.