South Australian Surf Forecast by Ben Matson (issued Monday 8th May)

Features of the Forecast (tl;dr)

• Average conditions at Victor on Tues, though small surf building on the Mid with OK winds
• Fun waves both coasts Wed, a little inco at times
• Small/easing but super clean down south Thurs
• Excellent weekend of waves with the Mid offering the best options
• Plenty of swell next week

Recap

Generally onshore across the South Coast all weekend with plenty of swell, though there were a few periods of light winds early in the mornings. The Mid was generally small and slow. Size has eased today with a continuation of the same winds, generally onshore. 

This week (May 9 - 12)

No change to the outlook for the next few days. 

A swell increase is expected to show overnight that'll boost size to 3-4ft down south on Tuesday, however it'll remain wobbly under a light to moderate S/SW airstream, the result of a large Tasman Low that generated 15-20ft sets across the Sydney coast today. There's a chance for an early period of light W'ly winds but it won't be enough to properly clean things up. 

The good news is that the swell will be on the build, and even if Tuesday doesn't pan out especially well, Wednesday should see a more pronounced improvement with light variable winds. Size should build to 3-4ft again across the Middleton stretch, generated a few days ago by strong activity way out near Heard Island, sitting at low latitudes, so there'll be lengthy breaks between the sets. But it's a worthwhile day to look for waves. 

On the Mid Coast, winds should be OK both days (variable tending light S'ly Tues, then light E'ly Wed) and although the swell wasn't generated in our preferred swell window, should have enough oomph to get through Investigator Strait and provide a few slow 2ft sets on the more favourable parts of the tide (expect things to be undersized early Tuesday). 

Thursday is then looking excellent at Victor with steadily easing swells and freshening northerly winds. It'll be small on the Mid with deteriorating conditions so definitely consider a road trip down south.

Surf size will then bottom out on Friday morning with a shallow front bringing about a non-consequential southerly wind change. Flag it.

There is a chance for a late pulse of W'ly swell for the Mid Coast, I'll detail that in the weekend notes below.

This weekend (May 13 - 14)

A blocking pattern is setting up in our swell window, which will be the main cause of the easing trend later this week.

However, there's usually something brewing on the upwards flank of any block, and in this case we have a significant cut-off low forecast to move through the Bight on Wednesday and Thursday. 

There's a couple of strong swells expected from this low. Initially, strong to gale force W'ly winds will develop south of Margaret River thru' Albany late Wednesday - see image below - generating a small flush of W'ly swell that may show late Friday in the gulf (timing is a little knife edge right now so I'll firm this up in Wednesday's notes).

However the primary W/SW swell generated by the parent low will be trailing some distance behind (see purple region on far left of the image above), and is expected to fill in overnight and into Saturday - despite the extra travel distance, it'll be a faster moving swell thanks to the higher periods. 

This is expected to create an excellent groundswell that'll show best at west facing coasts. Along the Mid, we shouold see consistent 3ft sets through the day, occasionally pushing 3-4ft at some of the more reliable swell magnets. 

And incredibly, it's looking like a weak high will ridge in from the west, creating light variable winds and thus clean conditions.

Down south, the strong westerly component in the swell direction won't favour a lot of size away from the swell magnets. I'll ballpark Middleton in the 3-4ft range though it'll be much bigger at exposed spots (expect a wider range in size than we normally see). The more sheltered regions like Chiton will be smaller than usual for a swell of this size.

Steadily easing swells are then expected Sunday with light winds likely to swing around to the north. There'll still be plenty of fun options on the Mid though.

All in all, an excellent weekend of waves ahead.

Next week (May 15 onwards)

The longer term is looking way more mobile for the following week with stacks of strong frontal systems through the Southern Ocean and a truckload of pre-winter groundswell on the make. 

More on Wednesday.