South Australian Surf Forecast by Ben Matson (issued Friday 16th October)

Best Days: TuesWed/Thurs/Fri: extended run of long period groundswell with generally favourable conditions. Should be decent options on both coasts.

Recap: It’s been tiny on the Mid Coast for the last few days. Victor was small but clean and fun on Thursday morning with moderate offshore winds, ahead of gusty onshores that kicked in a little earlier than expected, around 1:30pm. This morning offered poor conditions under fresh SE winds, but the erratic nature of this trough has seen the wind veer NE along the Middleton to Victor stretch this afternoon, cleaning up the wave faces (though the lineup is still very lumpy, as per exhibit B, below). Surf size has built to 3-4ft, being a mix of local windswell and underlying groundswell.

Ahh, the Mid

Ahh, Middleton

This weekend (Oct 17 - 18)

*This week’s Forecaster Notes will be a little erratic as Craig’s on annual leave*

The low pressure trough delivering this brief spell of NE winds is expected to push east overnight, bringing fresh southerlies to all regions on Saturday. There’s now very little chance for a window of light winds at dawn down south.

This is a shame, as there’s a nice groundswell building across the region and otherwise we’d see 3-4ft surf across the Middleton to Goolwa stretch. The new swell is however too south for the Mid Coast, so we’ll see tiny waves persisting into Saturday (and no useful windswell either, thanks to the southerly wind direction).

Local onshore winds will relax into Sunday, so conditions will try to improve but with no new swell on offer it’ll be small and weak at Victor, and tiny across the Mid. 

For the record, a small new S/SW groundswell is expected to glance the South Coast very late in the day, sourced from another polar low (similar to the one generating this afternoon’s energy) that has popped up on the charts since Wednesday’s notes were prepared (see below). I’m not expecting any arrival before mid-afternoon, and even then it’ll probably be average in quality thanks to the accompanying winds. If we’re lucky, we’ll see a few 3ft sets at Middleton on dark. 

Still, it’ll be worth keeping an eye on the wind obs in case the breeze backs off after lunch, with a chance for a fun lumpy session to finish the weekend.

Unfortunately, this swell will be too south in direction for the Mid. 

Next week (Oct 19 onwards)

A weak ridge of high pressure will dominate the region for much of next week, leading to generally light variable winds most days, tending E’ly Wednesday and then N’ly on Thursday ahead of a possible cold front on Friday. 

Sunday's late pulse of SW swell will ease slowly through Monday across the Victor region, though there should be some fun, slightly lumpy 3ft waves early as winds become variable. It’ll remain tiny on the Mid.

A series of powerful Southern Ocean lows in our far swell window are generating excellent long period swells that will arrive in succession from Monday evening onwards (leading edges Mon and Wed nights could be around 20+ seconds).

The latest model guidance has strengthened these systems a little more since Wednesday and also maintained their strength a little closer to the mainland, which will assist in maximising surf size potential throughout South Australian waters. The second swell in particular looks to be the biggest of the two. 

However, the large travel distance will result in very inconsistent set waves. This will be most prominent on Tuesday and Wednesday, when the first groundswell (see source above) will essentially be the only swell source in the water. On Thursday and Friday, the second long period groundswell will sit on top of decaying energy from the previous swell event, which (despite being smaller in size) will help to reduce the perceived inconsistency a little.

So, how big? At this stage I think we’ll see Tuesday building to 3-5ft across the Middleton to Goolwa stretch by the afternoon, possibly undersized early morning (expect flat spells of up to 15-20 mins between set waves). This swell should hold into Wednesday morning before easing through the day. 

Along the Mid Coast, both days have the potential for 2ft, maybe 2-3ft waves though it’ll be extremely inconsistent, and the upper end of this size range will probably be focused on the incoming tide. 

Thursday’s new swell (see source below) should rebuild to between 4ft and 6ft across the Middleton to Goolwa stretch, easing slowly through Friday. I like the look of this swell a little more for the Mid Coast too (mainly the storm track, which projects better up into our swell window, plus the duration of strongest winds), so there’s a little more confidence in there being 2-3ft waves both days, in fact Thursday could pick up a few bigger sets if we’re really lucky.

It's worth noting that despite the size and strength of the swell energy, it's often the consistency (or lack thereof) that ultimately has the biggest influence on the quality of your session - even if the waves are great when they arrive, it's obviously harder to jag a set when they're extremely infrequent.

Have a great weekend, see you Monday!