South Australian Surf Forecast by Ben Matson (issued Friday 23rd October)

Best Days: Thurs/Fri: New W'ly swell - great for the Mid - though local winds unsure. 

Recap: Thursday’s groundswell didn’t live up to expectations. However, we did see some nice waves through the afternoon - but only at a small number of locations on the Mid, whilst SE winds maintained average conditions at Victor for most of the day. Wave heights have eased back today, with freshening southerly winds across the South Coast, and small residual energy on the Mid Coast. As a side note, it’s interesting to see that the CdC buoy picked up larger wave heights on Thursday than the Cape Sorell buoy (off Tasmania), which is further south in latitude and on average usually recorded larger swells.

Fun Thursday options at U-Turns

This weekend (Oct 24 - 25)

With poor winds expected all weekend, there’s no need to waffle on about the synoptics (though, I’ll give it a crack, of course).

As mentioned over the last week, we’ve got a deep polar low firing up to our south-west, and this will generate a couple of new swells for the weekend that should increase surf size at Victor from 2-3ft on Saturday to 4-5ft by the afternoon, holding into Sunday. 

However, a complex, dynamic low pressure trough over SA will move eastwards, bringing gusty southerly winds to all regions by early morning. This will then be reinforced by a strong front (related to the polar low swell source). Winds will be S’ly on Saturday and should maintain strength from the SE into Sunday. These winds should also generate a short range S’ly tending SE swell for the South Coast, potentially of a comparable size to the underlying groundswell. 

Of course, conditions will be terrible. So keep your expectations low. 

Along the Mid Coast, fresh side-shore southerly winds won’t favour good surf conditions and will be too south in direction to generate any notable windswell (apart from those secret spots around Port Wakefield). The incoming groundswell from the polar low will also have been generated too far to the east of our swell window to allow for anything worthwhile, so expect small, windy conditions all weekend.

Next week (Oct 27 onwards)

Victor looks like a write-off for the first half of the week. 

We’ll see persistent SE winds Monday and Tuesday maintaining poor surface conditions. The breeze will relax on Wednesday and allow conditions to improve though we’re looking at regionally small groundswell conditions for the entire week, thanks to an upstream blocking pattern from the weekend onwards (Sunday’s swell will ease quickly through Monday).

As such, most of the swell on Monday and Tuesday will be local S/SE windswell, and then into the middle of the week it’ll be a small, weak spread of SE energy from a gusty (and somewhat unusual) E/SE fetch extending west from Bass Strait, below the SE region of SA. No major size or strength is likely though.

The Mid Coast will remain tiny to flat through this period, with light to moderate offshore winds each day. 

The rest of the week looks rather dynamic, though the models are vastly split on local solutions. 

Broadly speaking, a powerful, amplifying LWT developing west of WA over the coming days will become very active in our far W/SW swell window, and despite the long distance from the SA coast, will generate an extended run of good energy for the Mid Coast - the leading edge may arrive late Wednesday, but Thurs/Fri/Sat are all looking at overlapping W'ly swells in the 2-3ft range. It’s quite likely we’ll see at least one pulse bigger than this, pushing 4ft for a period too - the frontal sequence driving these lows is very impressive indeed.

However, there’s quite a bit of divergence on how the LWT will propagate west from WA longitudes and this will significantly affect our local conditions. The US model suggests a building ridge of high pressure and S’ly tending SE winds, whilst the European solution pushes a cut off low into the Bight, bringing SW gales at the same time the (unrelated) groundswell reaches a peak.

So, let’s wait and see how things pan out. But there’s stacks of swell on the way. 

Have a good weekend!