South Australian forecast by Craig Brokensha (issued Wednesday March 19th)

Best Days: South Coast today and tomorrow, Mid Coast Friday and Saturday, South Coast mid-late AM onwards Friday, South Coast Sunday morning, both coasts Monday morning

Features of the Forecast (tl;dr)

• Easing S/SW swell tomorrow with strengthening N/NW tending W/NW-NW winds, tending variable ahead of a late, strong S change
• Moderate sized W/SW-SW swell building Fri, peaking in the PM, easing slowly Sat
• Light to moderate but easing S/SE winds down South Fri AM ahead of late sea breezes, SE tending S/SW on the Mid
• E/SE-SE tending S/SW winds Sat on the Mid, E/SE tending S/SE down South
• Moderate + SW groundswell building Sun with E/NE-NE tending S/SE winds down South, E tending SW on the Mid
• Easing swell Mon with variable offshore tending S/SE winds
• Smaller Tue with variable S winds, freshening
• New moderate + sized SW groundswell for Wed PM

Recap

First up, read about the likely cause of blurred vission and throat irritation here.

The Mid Coast pulsed to 1.5ft-2ft through yesterday with clean morning conditions, while the South Coast was still chunky and to 4-5ft with improving conditions ahead of sea breezes.

This morning the South Coast was still a good 3-4ft with a reinforcing mid-period SW swell as the Mid Coast continued around 1-1.5ft and we’re due to see a strong S/SW groundswell arriving in the afternoon, kicking Middleton to 5-6ft as winds become variable from the NW.

This week and weekend (Mar 20 - 23)

This morning’s and this afternoon’s pulses of swell were generated by a strong polar low to the south of the country earlier in the week, and we’ll see the size peaking this afternoon/evening before easing back slowly through tomorrow.

The South Coast should back off from a good 3-5ft with 1ft sets across the Mid Coast and strengthening N/NW tending W/NW-NW winds through the morning are due to tend variable around midday ahead of a strong, evening S’ly change. This should provide plenty of options for a quality surf down South.

Unfortunately this change will leave lingering S/SE winds on the South Coast early Friday morning,  likely tending variable before lunch, creating improving conditions before late afternoon sea breezes kick in.

Swell wise, a weakening polar frontal system projecting up towards us yesterday and today should generate a moderate sized increase in mid-period W/SW-SW swell for Friday, building to 3-4ft across Middleton with fun 2ft sets developing across the Mid Coast. The morning will be best inside the gulf ahead of sea breezes.

The swell should start easing from 3ft across Middleton with 1-2ft on the Mid Coast Saturday under a light, morning E/SE-SE breeze, favouring the gulf over the South Coast.

Into Sunday we should see our new SW groundswell on the build, with a strengthening low moving in from the south-west of Western Australia due to generate a good fetch of W/SW gales through our south-western swell window while tracking east towards Tasmania.

A moderate + sized SW groundswell should reach 4-5ft+ on the South Coast with small 1-2ft sets across the Mid Coast into the afternoon, before easing Monday.

Local winds should tend E/NE-NE down South on Sunday morning (ahead of sea breezes) creating cleaner conditions, with Monday offering a variable offshore breeze ahead of strengthening S/SE winds.

Tuesday morning looks temporarily smaller with variable S winds, while a mix of moderate + sized mid-period and SW groundswell energy are due to fill in Wednesday.

The groundswell has already started to be generated by a strong but distant polar low forming west of the Heard Island region, with it due to push east while generating severe-gale W’ly winds. This low will then weaken on approach to Western Australia, adding the mid-period energy to the mix.

It’ll be inconsistent but Middleton should offer 3-5ft sets into Wednesday afternoon with 1ft to maybe 2ft sets inside the gulf though local conditions are still up for grabs. More on this Friday.