South Australian Forecast by Ben Matson (issued Monday May 12th)

Features of the Forecast (tl;dr)

• Small clean waves down Tues (tiny on the Mid)
• Small pulse of new swell down south Wed but winds are a little iffy (tiny on the Mid)
• Stronger round of new swells down south Thurs and (even more so) Fri with generally good winds
• Very small on the Mid Thurs but a nice pulse due Fri, clean with light winds
• Small waves on the Mid all weekend, a little windy Sat but light Sun
• Large swell Sat but poor winds
• Easing size and improving conditions Sun

Recap

The Mid Coast maintained small peaky waves all weekend and even today, still 1-1.5ft on Saturday, easing a touch early Sunday then rebuilding back to 1-1.5ft on Sunday afternoon, holding into this morning before easing a touch again this afternoon. Victor saw clean 3-4ft surf on Saturday ease to 2-3ft on Sunday and then 1-2ft this morning. Winds have been light each day and so conditions have been clean.

Good ol' Mid, eh? Never really gets that big, but sometimes pulses small straight groundswell lines for days on end. Surfcam grab from around half six this morning.

This week (May 13 - 16)

Small waves will persist on Tuesday despite the expected presence of long period swell. This energy was generated by a small, tight fetch near Heard Island mid-last week and most of its size will have decayed since generation (due to the large travel distance), so we’re looking at inconsistent leftovers in the 1-2ft range along the Middleton stretch and 1ft or so in the gulf. 

Light variable winds are expected all day (northerly if anything in the morning) so it’ll be a nice day for the swell magnets.

The latter stages of the same low (responsible for the absent long period energy) is developing a slightly better swell for Victor on Wednesday afternoon, but it’s not looking like a strong, consistent event at all. 

Wave heights should build to 2-3ft here (smaller early on), however a weak front will clip the coast around dawn, bringing the wind to the south - but probably without any strength. 

I’m not expecting much size on the Mid Coast either, as this second pulse was generated just east of the swell window. So, small residual energy is likely to maintain the tease.

Thursday and Friday are looking better though. 

A strong conveyor belt of fronts through the Southern Ocean - initially unfavourable aligned through our swell window - will generate a series of groundswells that will overlap through the latter part of the week ahead of a peak in size over the weekend.

Early indications are for 3ft sets at Middleton on Thursday and possibly early Friday before surf size builds up into the 4-5ft range by late Friday (bigger at the swell magnets). 

Along the Mid Coast, I’m a little concerned that Thursday may not lift much above a residual 1ft or so, however Friday should see bigger surf pushing into the 2ft range, albeit quite inconsistent. 

As for conditions, both coasts look to remain clean under a weak high pressure ridge creating light variable winds. 

So, all in all this is gearing up for another spell of fun waves for the Victor stretch, and a small window for the Mid too.

This weekend (May 17 - 18)

The peak of this swell cycle is expected on Saturday morning, however it will have been generated by the latter stages of the Southern Ocean progression as it rears up under the state - meaning the swell direction will be quite southerly. As such I’m not expecting a final boost along the Mid Coast, but instead a very gradual ease from Friday’s peak, from Saturday through Sunday. Both days should still manage 1-2ft waves though. 

Victor should see solid surf pushing 4-6ft at Middleton on Saturday, however we are unfortunately expecting moderate to fresh southerly winds to accompany it. The main cause of this will be a developing high in the Bight that’ll quickly push the responsible fronts to the east and over towards New Zealand, and firm a ridge against the eastern South Oz and Vicco coasts.

The Mid Coast will handle this wind better but it will be moderate cross-offshore S/SE in the morning, tending fresh cross-shore through the afternoon. 

Rapidly easing winds across all coasts on Sunday are unlikely to swing offshore with any strength down south, so whilst surface conditions will slowly improve, we can anticipate plenty of leftover wobble through the lineup. Expect wave heights to ease from 4-5ft to 3-4ft at Middleton with lumpy, average conditions on offer. 

Next week (May 19 onwards)

Looking further ahead and there’s nothing of any significance on the long term radar right now. I’ll have more on that in Wednesday’s update.