South Australian Forecast by Craig Brokensha (issued Wednesday 12th April)

Best Days: South Coast tomorrow, Mid Coast later Friday, both coasts Saturday and Sunday, South Coast Monday through Wednesday

Recap

Good conditions down South yesterday with an unexpected offshore breeze and solid 3-4ft of swell. The waves remained good most of the day with weak afternoon sea breezes.

Today the surf was clean again and with moderate amounts of swell right across the region.

The Mid Coast has hovered around the 1ft range with offshore winds, ideal for beginners.

This week and weekend (Apr 13 – 16)

The South Coast will be great again tomorrow morning with an offshore N/NW breeze, holding out until about midday early afternoon when a shallow W/SW-SW change will move through.

Middleton should still see 3ft sets during the morning, larger at Waits and Parsons while the Mid Coast will be around the 1ft range again.

With the weak nature of Thursday afternoon's change, Friday morning should see variable winds from the E/NE down South but the surf will be smaller as it bottoms out.

Some new W/SW swell will build through the day though, produced by a mid-latitude frontal system that's currently south of WA. An initial weak W/SW fetch is being closely followed by a better fetch of W/SW gales which will race towards us while weakening today and tomorrow.

The Mid Coast should see an increase in size through the day, from 1ft during the morning, up to 1-2ft into the mid-late afternoon. The South Coast is only due to be smallish through the morning, kicking to 3ft later in the day but with sea breezes.

Now, the stronger fetch of W/SW gales will generate a good pulse of W/SW groundswell for Saturday coming in at 2ft on the Mid Coast and a good 4ft off Middleton down South.

Light NE winds will create good conditions across both coasts during the morning with only light sea breezes into the afternoon.

The swell is expected to ease late Saturday, with a low point Sunday morning ahead of a strong new long-period SW groundswell.

This will generated today and tomorrow by a vigorous polar low developing south-west of WA.

A great fetch of severe-gale to storm-force W/SW winds should produce 3-5ft of inconsistent groundswell for the afternoon across Middleton, with smaller 1-2ft waves on the favourable parts of the tide across the Mid Coast.

Light winds, tending offshore on both coasts should create clean conditions, remaining light until early afternoon before sea breezes kick in.

Next week onwards (April 17 onwards)

Moving into next week and Sunday afternoon's increase in SW swell should drop back slightly and we're again looking at offshore winds through the morning from the NE.

Of greater importance is a vigorous polar frontal progression firing up south-west of the country over the weekend under the influence of the Long Wave Trough.

A very broad and elongated fetch of pre-frontal W/NW gale to severe-gale winds will develop south-west of WA, pushing east under the country through Sunday, generating a strong SW groundswell for Tuesday, building into the afternoon.

An even larger SW groundswell will be generated for Wednesday, produced by stronger severe-gale to storm-force W/SW winds on the tail of the polar frontal progression.

Sets to 6ft are expected across Middleton, while the Mid Coast should offer 2ft waves. Winds are still moving around a little but N/NE breezes are likely Tuesday with winds from the western quadrant Wednesday. More on this in Friday's update.