South Australian Surf Forecast by Ben Matson (issued Friday 23rd January)

Best Days: Sat: strong swell down south with good winds for most of the day. Plenty of surf on the Mid with mainly light winds through the morning. Sun: OK waves across the Mid but bumpy under a cross/onshore breeze. 

Recap: Thursday delivered bigger waves on the Mid Coast than expected, with inconsistent 1-2ft sets and light winds in place for much of the day ahead of a mid-afternoon sea breeze. Victor delivered fun waves through the morning with offshore winds ahead of a fresh onshore change around the middle of the day. Today, surf size has eased a little on the Mid Coast and winds are moderate onshore, and it’s bumpy down south with gusty SW winds. A new groundswell is due very late today but as yet there’s no sign of it at the Cape du Couedic buoy. As per Wednesday’s notes: keep an eye on the buoy for a noticeable J curve during the day, and then allow 3-5 hours for a transition to the coast: if the buoy isn’t showing Hsig above 3m by early afternoon, then the Mid’s chances for a decent late session (and also down south) will be somewhat lessened. 

This weekend (Jan 24 - 25)

Note: forecast notes will be brief this week as Craig’s away

So, this new groundswell is on the way - yesterday’s satellite observations have confirmed a healthy 30-40kt fetch in the Southern Ocean, with embedded core winds of 50kts, which means we're looking at a solid swell event displaying reasonably strong swell periods. 

The leading edge of the new swell is due to reach the coast very late today but it’s still uncertain whether we’ll see an appreciable increase in the surf zone before sundown. 

Nevertheless, Saturday’s shaping up pretty well across both coasts. An approaching front will swing winds around to a moderate west-nor’wester along the South Coast, and wave heights should reach 3-5ft at Middleton with 6ft+ sets at exposed spots like Goolwa and Waits. SW winds will probably develop later in the day so aim for an early surf for the best waves.

We should also see some reasonable lines across the Mid Coast throughout Saturday in the 2ft+ range on the more favourable parts of the tide (ie incoming), and winds are expected to be light and variable in the morning with a swing to the SW through the afternoon as the front approaches, with these onshore winds then freshening through into the evening. So, bumpy conditions are likely in the afternoon but there should be plenty of waves on hand.

On Sunday, SW winds are expected to dominate the broader coastline in the wake of the cold front, which means bumpy surf just about everywhere.

We’re not expecting any great drop in size along the South Coast, and even the Mid Coast should see a similar size range as per Saturday with a mix of easing groundswell and building windswell. Just keep a lid on quality expectations as you'll have to sniff around the sheltered spots for anything worthwhile.

Next week (Jan 26 onwards)

No major changes to the long term forecast. Sunday’s swell will ease slowly from Monday onwards, and winds will rapidly ease from the south, so expect average (but still strong) conditions down south and small leftovers on the Mid Coast with possibly a good window of cleanish conditions in the morning with more S/SE in the wind direction.

A regional blocking pattern will develop across our broader swell window during this time, which means we’re unlikely to see any notable swell events for some time beyond this. 

However, as mentioned in Wednesday's notes, a deep polar low is expected to form near Heard Island today, and then scoot along the ice shelf over the weekend - setting up a small but decent SW groundswell around Wednesday.

This swell looks like being only small to perhaps moderate in size (i.e. best suited to exposed coasts), but unfortunately local winds look dicey thanks to a large stationary high pressure system in the Bight that will probably deliver gusty south-east winds the Victor coast. This swell will be too small for the Mid Coast, so it’s probably worth letting pass by for now (I’ll update on Monday though).

Other than that, there’s nothing  of major interest in the long term with a general summer synoptic pattern expected to dominate for some time. I’ll take a look at the longer term outlook in more detail on Monday.