South Australian Forecast by Craig Brokensha (issued Wednesday April 23rd)

Best Days: Both coasts today, South Coast tomorrow, South Coast Friday morning, Saturday afternoon and Sunday morning on the Mid

Features of the Forecast (tl;dr)

• Easing surf tomorrow with moderate N/NE tending variable NW winds
• Moderate sized, inconsistent SW groundswell building Fri, peaking in the PM, easing Sat
• Light N/NW winds Fri AM ahead of a shallow S'ly change into the middle of the day/early PM
• Strengthenging S tending S/SW winds Sat (S all day on the Mid)
• Moderate + sized mid-period SW swell building Sat, peaking overnight, easing Sun
• Mod-fresh S/SW winds Sun (S/SE early on the Mid)
• Possible reinforcing S/SW swell Mon with variable tending S winds
• Easing surf Tue with E tending SE winds

Recap

The South Coast was a mess yesterday with some weak, clean 1-1.5ft waves across the Mid Coast, but our new SW swell filled in and offered slow 1-2ft sets into the afternoon with cross-shore winds.

This swell has come in a lot better than expected this morning across the Mid Coast with clean, consistent 2ft waves while the South Coast is improving with lumpy 4ft waves for the keen under a light cross-offshore wind.

This week and weekend (Apr 24 - 27)

Our current SW swell energy is due to ease back through tomorrow, with the South Coast being the pick under a N/NE offshore, tending variable N/NW into the afternoon. Middleton should be a fun 3ft, easing through the day with the Mid coming in tiny but wind affected.

Come Friday we should see a new, inconsistent SW groundswell filling in, with it generated by a distant but strong fetch of severe-gale W’ly winds on the polar shelf, east of Heard Island earlier this week. 

The swell is due to build through the day, coming in at 2-3ft through the morning before reaching 3ft+ into the afternoon while the Mid Coast looks to only be 1ft, if that.

A trough is expected to move in through the day but the morning should be clean with a light N/NW offshore down South, shifting S’ly around midday/early afternoon.

Come Saturday, the trough will move further east, opening the coast to strengthening S’ly tending S/SW winds.

Swell wise, our building mid-period SW swell energy is still on the cards, with an initial small polar low that’s currently east of the Heard Island region due to project a fetch of strong to sub-gale-force W/SW winds up and towards us over the coming days. 

While not overly strong the persistent nature and track are good, with a moderate sized mid-period SW swell due from this source Saturday, building through the day ahead of a peak later/overnight.

A smaller front generating some additional W/NW winds through our swell window should slow the easing trend Sunday.

Size wise, Saturday should build to the 4ft+ range across Middleton later, easing back from, 4ft on Sunday morning while the Mid Coast looks to come at 1-2ft on the favourable parts of the tide later Saturday and Sunday morning.

Winds as touched on above aren’t great Saturday but should hold out of the S’th all day inside the gulf with S/SW winds on Sunday, likely to be S/SE at dawn across the Mid Coast.

Into Monday more variable breezes are likely with a possible new reinforcing mid-period S/SW swell but the models diverge regarding this. Regardless, winds look to have an easterly bias as the energy eases through Tuesday, but more on this Friday.