Southeast Queensland and Northern New South Surf Forecast by Ben Matson (issued Wednesday 16th June)

Best Days: Late Fri/Sat/Sun: large south swell but very windy at times, best suited to SE Qld on Sat/Sun where it'll be smaller but much more manageable. Mon: mix of E/SE and S/SE swells with improving conditions. Tues/Wed: fun small south swell with good winds (don't expect much in SE Qld). 

Recap: Great waves across the open beachies over the last few days with a slowly easing S/SE swell and generally light winds. Smaller surf in SE Qld due to the swell direction.

This week (July 17-18)

Today's conditions will ease further throughout Thursday, and freshening W/SW winds will confine the best waves to the exposed beaches of Northern NSW. Not much surf is expected north of the border.

On Friday, a vigorous cold front will cross the southern NSW coast early morning, swinging fresh westerly winds to a strong sou’wester (in the Mid North), with winds remaining more W/SW in the north. 

A broad fetch will then develop across the western Tasman Sea rather quickly during the morning, S/SW in direction off the southern NSW coast and more SW off the Northern NSW coast (as the front is steered by an amplifying Long Wave Trough), and in doing so will whip up a large south swell that’s due to peak across most regions on Saturday as the LWT anchors itself across New Zealand longitudes. 

It’s hard to be confident just how far north this south swell will penetrate by late Friday - for surfing purposes at least - but right now it’s unlikely that we’ll see much activity north of the border. In fact I think that the northern extent of Friday’s (rapid) south swell increase will probably be about Yamba or maybe Ballina at a stretch.

South of this arbitrary line is likely to be a much different story, especially with increasing southerly latitude. And the most interesting aspect about Friday's outlook is the speed at which we’re likely to see wave heights ramp up across the coast. Most of the morning is expected to be very small (1ft south facing tops, near-flat in SE Qld) but by late morning there should be more visible 2ft to maybe 3ft sets and from then on the increase should kick in relatively quickly, with exposed locations south of Coffs Harbour likely to reach 6-8ft by the end of the day.

However, with gale force SW winds on hand you’ll have to tuck into a sheltered southern corner for the only rideable conditions. And bear in mind that the bulk of this size will push through really late in the day - so protected corners may not be worthwhile until mid-afternoon onwards.

This weekend (July 19-20)

We’ve got one major change for the weekend forecast since Monday's notes - removing the 6-8ft estimate and replacing it with 10ft+ for Saturday at south facing beaches. Our surf forecast model is calling even bigger waves (12-15ft south facing in Coffs) however this is probably a result of windswell contamination due to the close proximity of the fetch to the mainland (which the model can't resolve very well).

In any case, strong to gale force SW tending S’ly winds will write off all but the most sheltered locations on Saturday, and with a limited number of locations fitting this description in Northern NSW, expect high concentrations of surfers at anything remotely rideable. There's also likely to be a very large sweep up the coast, so make sure you spend plenty of time assessing conditions before you paddle out, even if it's only three or four feet in a southern corner - as down the beach (where the sweep will invariably drag you) could be much bigger. 

A better option on Saturday will be the Gold and Sunshine Coast points. Ordinarily, south swells generated west of about 160E are often whittled away to nought by the time the energy bends in around Cape Byron and then Point Danger. However the sheer size, strength and scope of this system will easily override the directional deficiencies (I came up with that term last week and I liked it so much I’m gonna use it again!), which means we should see plenty of size across the semi-exposed points throughout SE Qld, probably building to 3-4ft by Saturday afternoon and into Sunday morning. 

Wave heights will ease slowly through Sunday but there’s still likely to be some very large waves at exposed south facing locations in Northern NSW early morning, probably 6-8ft or so - with much smaller surf at protected spots. Expect smaller conditions into the afternoon with gusty but slowly abating winds.

Next week (July 21 onwards)

Monday will see steadily easing swell from the weekend with abating SW tending S’ly winds in most locations. It’s likely that Northern NSW will still be too wild and wooly at exposed beaches but the points should have fun waves on offer as the energy starts to wind down. SE Qld will probably still be your best bet however semi-exposed points will probably be a less consistent 2-3ft by this time, becoming smaller into the afternoon.

A polar low is expected to clip the southern Tasman Sea on Sunday, generating a smaller but long period south swell for later Monday (across the Mid North Coast) and most of Tuesday (inconsistent 3ft+ sets at south facing beaches in Northern NSW). This will replace the steadily dropping S/SE swell from the weekend's source. However we won’t see much of this swell north of the border - Monday and Tuesday will mainly consist of easing S/SE swell from the weekend in SE Qld.

Also expected in the water on Monday is a small SE swell generated by a secondary low just off the west coast of NZ’s North Island on Saturday morning. No great size is expected here but we might see some fun 2-3ft sets at times.

The Long Wave Trough responsible for the entire period of swell will then slowly clear east of New Zealand early next week, and as a consequence our southern swell window will start to dry up. As such we’re looking at slowly easing long range south swell from Wednesday onwards, with no other long term swell sources on the charts. Tune in Friday to see if the weekend’s large south swell is still on target!