South Australian Surf Forecast by Ben Matson (issued Monday May 11th)

Features of the Forecast (tl;dr)

• Small clean surf at Victor on Tues, chance for a very late pulse of new swell (both coasts)
• New swell showing best Wed/Thurs; fun small waves on the Mid, better at Victor
• Easing Fri with great conditions at Victor
• Small blustery conditions Sat with a poss late NW stormy on the Mid
• Solid bumpy surf on Sunday; chance for a window of OK conditions at Victor but initially small
• Large and onshore Mon, easing and improving rapidly Tues
• Plenty more swell beyond this!

Recap

Small waves on the Mid over the last three days, bumpy on Saturday with onshore winds but just enough size for beginners and longboarders Sunday and Monday. Wobbly waves at Victor on Saturday under a westerly breeze but Sunday and Monday were clean with offshores. 

This week (May 10 - 13)

Generally light variable winds all week should keep conditions clean across all coasts.

If anything, we'll see the trend veer to the E/NE though no major strength is expected. This should be ideal for both coasts; just bear in mind there may be occasional brief periods at Victor where conditions may become a little ruffled if it perks up from the E/SE.

As for size, the current easing trend will bottom out into Tuesday morning, favouring exposed spots. Very little surf is expected on the Mid. 

Around lunchtime, the leading edge of a new groundswell is expected to reach the coast and we should see a sharp uptick in peak swell periods at the CDC buoy, sourced from an impressive though slightly off-axis low well south of WA over the weekend. 

Although only low confidence, we should start to see an upwards trend in surf size very late in the day at both coasts, so it’ll be worth scouting the cams for signs of life from early afternoon onwards (once the buoy has detected the new energy, and allowing a decent spell for travel time).

Wednesday is a better bet for this new swell, which should produce clean though very inconsistent 2ft surf on the Mid, and 3-4ft sets at Middleton, bigger at the regional swell magnets. 

Modest secondary fronts trailing behind the main low pressure system will slow the easing trend from Thursday, so expect a similar size range early, abating gradually into the afternoon and then further into Friday. However there should still be small waves on the Mid to close the working week, and Victor will be great as winds swing around to a light to moderate northerly. 

This weekend (May 14 - 15)

We’ve got a blustery weekend ahead.

It’s a classic winter frontal pattern, that may become supercharged thanks to a tropical infeed, courtesy of TC Karim - way out near the Cocos (Keeling) Islands at the moment - which is expected to move south and eventually merge (as a weakened tropical low) with the broad scale frontal system sweeping up from the Southern Ocean.

First off, Friday’s easing swell trend will continue into the weekend. Winds will be out of the north, but strong and gusty at times thanks to approaching front (see below), so it’ll be a tricky surf at the Victor swell magnets. 

The Mid Coast won’t see any new groundswell by this time, only local windswell - which will be proportional to actual (not modeled) wind strength in the gulf - if it reaches 20kts it'll push 2ft, if it reaches 30kts it'll push 3ft, if it reaches 40kts it'll push 4ft+ (and so on). In any case, wind direction will be N’ly tending NW through the morning then potentially gale force W/NW mid-late afternoon, so pencil in a surf at the metro beaches if you’re desperate. 

The first of a series of fronts will then cross the coast overnight, and Sunday will see temporarily easing W’ly winds, though still moderate to fresh at times. They may back to the north-west through the day too, as the next system rears up from the west. 

Saturday’s front will have travelled very far north through the Bight and will have generated a strong westerly swell that should reach a bumpy 3-4ft on the Mid. We may even be lucky to see a period of lightish winds in the morning, but it won’t clean up all of the lumps and bumps.

This swell is expected to initially be too westerly in direction for Victor, so we’ll see small surf on Sunday morning but with a building trend through the day as a strong SW swell from a polar low make landfall (towards a peak on Monday). 

Local winds are tricky for Sunday down south but we should see a window of opportunity for reasonable waves.

Next week (May 16 onwards)

The parent polar low to the weekend’s fronts looks very juicy on the charts (see above), we'll see plenty of size and long periods (in the 17-18 second range) lighting up the entire southern Australian coast with strong swells. But there'll be a lot of noisy windswell in the mix from local sources too.

Victor should pick up 6-8ft sets on Monday and the Mid Coast should hold 3ft+. Winds will be fresh onshore but should gradually abate through the day. 

Better surf is expected on Tuesday as the wind veers back to the north and surf size eases to 4-6ft at Victor, with 2-3ft surf on the Mid. 

Looking further ahead, and a winteresque conveyor belt of low pressure systems are set to deliver several more strong swell events behind this (mid-late next week and the following weekend), with pockets of favourable winds on hand. 

More on this in Wednesday’s update.