South Australian Surf Forecast by Ben Matson (issued Monday 29th December)

Best Days: Tues: improving conditions on the Mid Coast, brief window of favourable early conditions down south. Wed: much better down south with light winds. Sun: chance for a small clean afternoon swell on the Mid Coast.

Recap: Poor surfing conditions were on offer Saturday, but a strong new groundswell filled into the South Coast on Sunday morning and winds were light offshore until about 11am when southerly winds developed at Hindmarsh Island (becoming fresh through the afternoon). In fact, winds remained NW for much of the day at Parawa - west of Victor Harbor. And to throw a further curveball, Cape Willoughby - at the eastern tip of Kangaroo Island, just 38km from Parawa as the crow flies, and 55km from Victor Harbor - recorded light E’ly tending SE winds throughout the day. So there were certainly windows of opportunity all day across the region.

This morning a strong front crossed the coast and has whipped up a small stormy for the Mid Coast in the 2-3ft range. Wave heights are much bigger down south but a brief window of early offshore winds has disappeared, with strong onshore winds padding out much of the day.

 This week (Dec 30 - Jan 2)

*forecast notes will be brief this week*

We’ve got another round of swell on target for Tuesday. This will comprise a mix of long range W/SW groundswell (from a polar front that developed over the weekend) in addition to a secondary short range SW generated by another front tracking behind today’s system. 

This next front isn’t quite as strong, and is travelling a little more south in latitude, so local winds should be lighter - especially along the Mid Coast. In fact by the afternoon they should be light southerly, so surface conditions should be on the improve. A late S/SE land breeze may possibly fill out the last few hours of daylight too.

As for wave heights, along the Mid Coast we’re likely to see peaky waves in the 2ft+ range on the more favourable parts of the tide (but smaller through the middle half of the day). The South Coast should manage bigger waves around 3-5ft at Middleton, and we should even see winds veer back to the W/NW near Victor Harbor for a few hours early morning, before W/SW winds redevelop from mid-morning onwards. 

Wednesday looks pretty good all round, but there probably won’t be quite enough surf for the Mid Coast as all swell sources trend downwards. There’s likely to be some residual lines in the gulf somewhere in the 1ft range, possibly nudging 2ft every so often, but it’ll be much slower and less consistent. Conditions will be nice and clean though with light variable winds. 

Down south, these light winds will accompany a slow drop in surf size that should start out in the 3-5ft range at Middleton but be a foot or two smaller by the end of the day.

On Thursday, another front will rear up from the south, bringing about a SE wind change probably in the afternoon. With wave heights continuing to ease you’ll have to aim for an early session to make the most of the cleaner conditions. Don’t expect much more than a tiny residual line in the gulf.

At this stage Friday is on track for some fun clean waves, thanks to the arrival of a small new swell generated by the front passing well south of the state. Middleton should manage 3ft sets into the afternoon (smaller earlier) and winds look to be offshore from the northern quadrant - there may be some leftover lumpiness from Thursday's change but on the whole there should be some very worthwhile options throughout the day, probably best in the afternoon.

Friday's new swell will probably have too much south in its direction to benefit the Mid Coast, so again - anticipate very small lines of teaser swell in the sub 1ft range.

(note: the initial version of this forecast had fresh SE winds for Friday - holding on from Thursday's change - but the latest model data now suggests this may quickly lose strength overnight, so these notes have been amended to reflect ).

This weekend (Jan 3-4)

Saturday looks like being a typical summer’s day of waves for the SA region, thanks to a developing high in the western Bight and a series of fronts skirting the Southern Ocean south of the state. 

This will probably maintain fresh S/SE winds across most regions, along with mainly small swells that’ll be too small for the Mid Coast, and rendered useless down south due to the prevailing onshores. 

Only thing we can hope for at this stage is a break in the (forecast) synoptic pattern over the future model runs - are there’s a chance that we may see a brief window of opportunity early Saturday morning - but I’ll have more details on that over the coming days. 

Sunday has more promise, centred around the Mid Coast. A polar low is modelled to develop east of Heard Island later Wednesday, which could very well power up and into our swell window later this week, generating a small groundswell for the Mid Coast Sunday afternoon (and into Monday). 

This should end up providing a nice lil’ summer swell in the 2ft range for the afternoon session (along with moderate SE winds, continuing from Saturday), but we’ll have to wait to see how the models pan out over the coming days to improve on the confidence levels. Either way, expect more summer mush down south too.

Next week (Jan 5 onwards)

Current indications are for a temporary blocking pattern to develop south of the state over the weekend, as a series of strong fronts strengthen SW of West Oz. This suggests an easing trend following the Sunday/Monday swell - perhaps for a couple of days - before a strong SW swell pushes through during the second half of next week. More on this in Wednesday’s update.