South Australian Surf Forecast by Ben Matson (issued Friday 15th September)

Features of the Forecast (tl;dr)

• Fun waves all weekend on both coasts, biggest Sun
• Light winds and fun surf Mon with light winds
• Bumpy conditions on the Mid Tues/Wed with a frontal passage (and posisle small stormy), Thurs/Fri looking much better
• Clean at Victor Tues, bumpy Wed then improving from Thurs
• Plenty of swell all week

Recap

Surf conditions have remained clean at Victor for the last two days, with small residual swells maintaining 1ft waves at Middleton on Thursday, bumping up a little today with a new swell. The Mid Coast saw small lines of new W'ly swell throughout Thursday (wind affected under a moderate northerly) and this morning (wind affected under moderate north-westerlies) though it's glassed off this afternoon. Wave heights are now building across the region with clean 2ft sets showing at the reefs, though the high tide isn't helping much.

Late Friday arvo swell building along the Mid Coast

This weekend (Sep 16 - 17)

No major change in the weekend outlook.

Light variable winds are expected on the Mid both days, whilst W/NW winds will perk up at Victor on Saturday before a variable pattern kicks in for Sunday. We may see late southerlies across both coasts (Sunday) as a weak high ridges in from the west, but most of the day should see favourable conditions.

As for surf, the overarching trend is for several overlapping W/SW pulses to provide plenty of waves across both coasts, though it'll be a slow start down south on Saturday owing to the dominant westerly direction.

The first swell is pushing through now (a few hours behind schedule, but trending the right way), it'll hold through Saturday morning with steady 2ft sets on the Mid and a similar size at Middleton, before pushing 3ft across both locations into the afternoon with the arrival of a new, longer period swell (so, keep an eye on the CdC buoy and expect a lag time of 3-4 hours to the coast). Expect bigger surf at the Victor swell magnets like Goolwa and Waits.

Sunday will see this new longer period swell draw out the consistency a little better, and the Mid should maintain inconsistent 3ft surf for most of the day. Down south, we'll see a little more size than mentioned in Wednesday's forecast, as the synoptics have improved a little since then. Core wind speeds around an embedded low contained with a mobile frontal conveyer belt below the continent are looking very good, upwards of 50kts, which may override some of my earlier directional concerns.

This should push Middleton into the 3-4ft range, with bigger sets at Goolwa and Waits though expect only small surf throughout the Chiton stretch due to the westerly swell component.

All in all, it's looking like being a really nice weekend of waves across both coasts.

Next week (Sep 18 onwards)

A weak high pressure ridge will maintain variable winds on Monday, though there is a slight risk for lingering S'ly winds at Victor in the morning (I'll try to update over the weekend as the models update).

From there on, the conveyer belt of Southern Ocean fronts will restrengthen W/NW winds on Tuesday, tending W/SW into Wednesday as a front crosses the region. Lighter winds are then expected to finish off the weekend as the fronts clear to the east.

As for surf, the conveyer belt will maintain plenty of surf all week, holding somewhere between 2ft and 3ft mark most days on the Mid (biggest through the incoming tide), though the Tues/Wed frontal passage will add a decent percentage of windswell loading into the mix. Thursday and Friday are looking really nice with plenty of fun waves and much better conditions.

Victor should also see an underlying groundswell either side of 3ft at Middleton all week (bigger at the usual swell magnets etc) though there'll be another foot or two on top trailing Wednesday's frontal system as well.

Therefore Thursday could provide a decent day of sizeable lumpy waves as the local wind starts to throttle back.

I'll have more details on that in Monday's update.

Have a great weekend!