Easing surf, ahead of a complex mix of south swells for the weekend

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Ben Matson (thermalben)

South East Queensland and Northern New South Wales Surf Forecast by Ben Matson (issued Wednesday 15th July)

Best Days: Thurs/Fri: small pulsey south swell in Northern NSW with offshore winds. Only small in SE Qld. Sat/Sun: solid combo of building south swells, best for protected spots and points (albeit much smaller in size). Should be some small waves across the exposed Qld points. Light winds expected south of Yamba on SunMon/Tues: easing S'ly swell wth light winds. Also a small trade swell for SE Qld. Wed: more small trade swell for SE Qld and a moderate, very inconsistent south swell for Northern NSW. 

Recap: A strong S’ly swell built across Northern NSW and SE Qld on Thursday, punching well above forecast expectations. I’ve written an article on why this occurred (well worth a read if you have some time). Thursday’s south swell has then slowly eased in size today. Conditions have been clean with light offshore winds across all coasts.

This week (July 16 - 17)

The overall trend for Thursday and Friday is for more south swell, albeit smaller in size than the last two days.

The current energy is on the way out and will ease throughout Thursday. South facing beaches across Northern NSW should see inconsistent 3ft+ sets early, but but it’ll be smaller elsewhere, and wave heights will become smaller throughout the day. 

In SE Qld, I’m not expecting much size, just an inconsistent 1-1.5ft at most open beaches with stray bigger 2ft+ sets at south facing beaches early morning, becoming smaller throughout the day. It’ll be quite inconsistent too, but clean across the beaches with offshore winds.

A new pulse of south swell is expected to push up along the Southern NSW coast during the day, and may nose into the lower Mid North Coast late afternoon. This was generated by a low that formed SW of New Zealand’s South Island on Tuesday, in associated with the broad pattern occupying the Tasman Sea this week. However, the low wasn’t particularly strong and it hasn’t remained in the swell window for very long, so its influence will be brief across the coast.

That being said, I think the swell models are undercooking the size potential from this system (they're calling just 2ft at Northern NSW’s south facing beaches on Friday). I think we’ll see slightly bigger waves - albeit very inconsistent - in the 3ft+ range at times across south swell magnets, however SE Qld will probably dip out with surf size continuing in the 1-1.5ft range on Friday, with a few bigger sets at south swell magnets.

Note: there may be a slight lag on this swell in the Far North (and SE Qld) early morning, so the afternoon is expected to see the most size here. Keep in mind that Northern NSW beaches not open to the south will also be much smaller in size too. 

As for Friday’s conditions, we’re looking at freshening W’ly winds tending strong and gusty W/SW then SW late afternoon as a low pressure system forms off the Sydney coast. We won’t see any new swell from this system until Saturday but local winds will certainly strengthen across the coastal margin, especially the Mid North Coast (which will be located closest to the developing low).

This weekend (July 18 - 19)

We’ve got four individual sources of south swell on target for the weekend, all of which will overlap at some point. Here they are in no particular order:

(1) The low developing off the Sydney coast on Friday will momentarily direct strong S’ly winds through our swell window before its whisked off to the east.

(2) A cold front racing up through the lower Tasman Sea from the Southern Ocean will become absorbed into the latter stages of Friday’s coastal system. This is great for surf potential (as it’ll renew a reasonably solid round of energy from the south) but it also invigorate the southerly airstream across the region.

(3) A deep polar low tracking well below the continent this afternoon is expected to generate a small long period south swell on Saturday (it’ll be hard to detect under the noisy windswell though)

(4) A second deep polar low and associated cold front below the continent tomorrow is expected to push through the Southern Tasman Sea into Friday (see chart below), generating the best southerly swell of the weekend. It’s expected to build throughout Sunday.

The dictating factor this weekend will be local winds. The coastal low (as a side note: may be an ECL, but not sure yet) and the first cold front will provide fresh S’ly winds across most regions on Saturday, so although there’ll be a lot of surf (at Northern NSW's south facing beaches, say 4-6ft), they’ll be blown out. Sheltered spots and semi-exposed points look to be the best option on Saturday, with smaller better waves.

SE Qld should also see some small surf on Saturday but the overall fetch alignment and swell period doesn’t look conducive for any major size. So, expect small runners on the outer points and bigger bumpy beach breaks at the northern ends. 

Sunday looks much better, thanks to a large high pressure system ridging in from the west. This will rapidly ease the local southerly flow across most of Northern NSW - up to about Yamba or thereabouts - creating regions of light W/SW winds. North from Yamba into SE Qld, we’ll see a lingering SE flow but the’ll be pockets of SW winds early (i.e. Coolangatta). Expect a few wobbles on the surface early morning though. 

As for size, Northern NSW’s south facing beaches are looking at 4-6ft surf again on Sunday, with smaller 3-5ft waves at the semi-exposed points. In SE Qld most beaches will probably hold in and around the 1-2ft mark but the semi-exposed points should nudge a little higher than this at times, and south swell magnets should be another foot or two bigger. 

Next week (July 20 onwards)

Monday and Tuesday are looking very good across the region with easing southern energy from Sunday's pulse, and mainly light winds as the high pressure system moves slowly east.

A moderate trade flow developing across the Coral Sea from Sunday should generate a small E’ly swell for SE Qld (best suited to the Sunshine Coast) for the first half of next week. No major size is expected, probably 2ft across the Gold Coast and 2-3ft on the Sunshine Coast. Certainly some fun small beachies for the grommets.

Elsewhere, another deep polar low off the ice shelf over the weekend looks set to generate a very powerful, albeit distant southerly groundswell that’s modelled to arrive across the Northern NSW Coast on Wednesday. It’ll only favour south facing beaches, but we may see some inconsistent 4ft sets at times. More on this in Friday’s update.


lostdoggy's picture
lostdoggy's picture
lostdoggy Thursday, 16 Jul 2015 at 1:48pm

Pretty solid out at Nth Wall this morning.