South Australian Surf Forecast by Ben Matson (issued Wednesday 20th September)

Features of the Forecast (tl;dr)

• Easing onshore winds Thurs, fun surf on the Mid into the afternoon (lumpy early)
• Smaller and cleaner again on Fri with light winds
• Small inconsistent swells for the weekend with generally light winds (best AM)
• Small+ surf next week with generally OK conditions most days

Recap

Small leftover 1-2ft surf on the Mid early Tuesday built in size to 2-3ft in the afternoon, but onshore winds freshened at the same time so conditions were poor. Today's seen bigger, bumpier surf around 3-4ft under gusty onshore winds, with small weak waves on the metro beaches. Victor saw easing swells to 2-3ft at Middleton on Tuesday, easing further into the afternoon and clean all round with offshore winds. Size has kicked to 3-4ft with a new swell this morning, and bigger waves are expected this afternoon.

Wonky lunchtime sets on the Mid

This week (Sep 21 - 22)

Building swells today will peak overnight and then gradually ease through Thursday, though trailing SW winds behind the front will maintain poor conditions down south.

We'll see slightly better conditions on the Mid as the local wind should throttle right back, though early morning will probably still see a lingering onshore, and there'll be lumpy leftovers as a result - but it'll clean up as the day progresses, with light variable winds likely after lunch, and possibly a late land breeze from the SE towards dusk.

Fortunately, the surf potential remains high for both coasts thanks to an active storm track through the Bight. The Mid Coast should maintain 2-3ft+ sets at the reliable reefs on the more favourable parts of the tide, and Victor should see this afternoon's peak maintaining 4-6ft sets at Middleton early, before slowly easing through the day.

Light to moderate easterly winds will probably develop overnight Thursday, leading to lumpy but improving conditions at Victor on Friday as we see early NE breezes ahead of an afternoon seabreezey sou'easter. Size will abate from 3-4ft at Middleton early, smaller later.

Wave heights will also ease along the Mid Coast on Friday though there should be fun 2ft sets for most of the day, maybe the odd bigger one with the help of the tide. 

Also, keep an eye on the CdC wave buoy for signs of a big jump in peak swell periods (22-23+ seconds) from the huge storm off South Africa late last week. However, I'm not expecting any major change in local surf conditions on Friday as a result. 

This weekend (Sep 23 - 24)

No change to the weekend outlook, with a weak high pressure ridge maintaining generally light winds at times both days. 

In addition to easing swell from Friday, there'll be two additional swells in the water though I don't think they'll contribute much size to the region. 

The first is the extra-long period energy mentioned above, which was generated below South Africa last Thurs/Fri (so, a travel time of more than one week). Significant wave decay will have occurred over this time frame and the fetch was actually aimed into Indonesia, so sets will be extremely infrequent and small. It's certainly not a swell event to bank on (especially on the Mid).

The second swell will have been generated by pre-frontal NW winds near Heard Island, ahead of a deepening polar low (that will initially be aimed outside of our swell window). Again, it's not well aligned within our swell window so the sideband energy we receive will be only small.

Therefore, expect small surf with long breaks between the sets, up to 2ft at Middleton, bigger at the regional swell magnets, and occasional small peelers on the Mid too (no more than 1ft, maybe 1-2ft on the tide, and more than 20 mins between waves at times).

Conditions look generally clean for the Mid with light offshore winds; down south we'll see early offshore winds and moderate south-east sea breezes. So make the most of the mornings.  

Next week (Sep 25 onwards)

The storm track looks very active SW of WA for next week but it won't push very close to our region - though an unrelated short wave feature will bring about a couple of days of westerly winds mid-week.

Therefore, we're looking at small to moderate swells for much of the week, pulsing between 2ft and occasionally 3ft across the Middleton stretch, and even some small waves pulsing around 1-2ft along the Mid too. Most days should see light winds though Wednesday has a shallow westerly change on the cards. I'll fine tune the specifics on Friday.

Bigger surf prospects are on the radar for the following week, but I'll have more on that in Friday's update.

See you then!