South Australian Surf Forecast by Ben Matson (issued Monday 19th May)

Best Days: Tues PM - keep an eye on the South Port surfcam for a possible sneaky arvo increase. Wed/Thurs/Fri/Sat/Sun: great waves at Victor.

Recap: Pumping waves all weekend. Small on the Mid but solid down south, easing into today. Nice and clean with light to moderate N’ly winds.

This week (May 20-23)

*note: forecast notes will be somewhat brief this week as Craig is on leave*

What a week of waves, eh? Victor’s seen the triple combo of good swell, good winds and good banks - the likes that only seems to grace the coast once every couple of years. And reports from Yorkes and the West Coast have been nothing short of epic too. Hope you've been getting some!

The good news is that there’s still plenty of great surf still on the way. However the key differentiator for this week is that after an extended period of quality swell with a lot of west in its direction, we’re now looking at around five or six days with more southerly orientation.

The source of these new swells is a seemingly endless supply of fronts (I’ve previous used the word ‘conveyor belt’, which paints the right kind of picture) that are developing and still expected to develop midway between the ice shelf and Tasmania, stretching west to about 110E early in the forecast period, but generally doing most of its swell production east of 130E. See below for an example of the current position.

Now, this region is located outside of the Mid Coast’s swell window, and the resulting swells will be quite S/SW, in fact the tail end of this progression will result in an almost straight southerly swell pushing into the region.

However, it’s certainly no problem for the South Coast, in fact it’s a bonus because - despite the generally smaller size - these swell directions provide a more uniform size range across the entire South Coast. So there should be some more options available.

But to backtrack a little further, the weekend saw the development of a moderate but ultimately sneaky SW fetch immediately off the ice shelf, between 90-105E. This fetch was positioned far enough back into the swell window to favour the Mid Coast - however the resulting swell we’ll see from it won’t be very large die to the enormous travel distance. It’s expected to arrive Tuesday morning sometime (probably not at dawn, but likely before lunch) so keep an eye on the South Port surfcam for signs of an afternoon kick. I’m crossing my fingers for a couple of stray 1-2ft sets, that’ll be clean under a light variable wind. It'll be very inconsistent though (if and when it arrives).

This swell will combine with another S/SW swell to create a much more prominent increase along the South Coast, in the 3-4ft range at Middleton by Tuesday afternoon. Early offshore winds will probably swing onshore during the day but there won’t be much strength, however Wednesday is a better time to take advantage of this (slowly easing) swell as winds will shift back to the north.

Slowly easing swells are then expected through the rest of the week, still enough for good waves down south under a freshening NW winds Thursday that’ll tend variable Friday. A late arrival of new S’ly groundswell is expected on Friday afternoon that’s well worth keeping an eye out for.. Middleton should reach 3ft on dark.

In the gulf, Tuesday afternoon’s possible swell increase may linger into Wednesday morning but it’ll trend downwards from the afternoon, leaving tiny residual energy through Thursday and Friday.

This weekend (May 24-25)

We’ve got another cracking weekend coming up for the Victor coast, with the final energy in a series of S/SW swells pushing through, accompanied by moderate N/NE winds both days. There won’t be much swell in the gulf so take advantage of another unreal weekend down south! Early estimates have Middleton offering inconsistent 3ft sets, with bigger 3-4ft+ waves at Goolwa and Waits. Expect long breaks between ‘em though as this swell will have travelled quite a long way.

Longer term (May 26 onwards)

All of this S/SW activity is partly due to a major blocking pattern upstream, south of Western Australia that’s expected to persist all week. An amplifying long wave trough across the southern Indian Ocean throughout the forecast period looks like it’s only going to move slowly eastwards, and all of the models have a range of solutions for the South Oz swell window in the long term that incorporate a large cut off low in the Bight over the weekend and early next week.

Right now it’s too early to have much confidence in the specifics, however it’s reasonable to expect a strong, building windy west swell (benefiting the Mid Coast) around Monday of next week, with a return SW swell favouring Victor Harbor shortly afterwards (say, Tues/Wed).

Looking beyond that and long period SW swell originating form storm activity associated with the Indian Ocean long wave trough is then likely to start filling in during the mid to latter parts of next week. More on all of this in Wednesday’s update.