South Australian Forecast by Craig Brokensha (issued Wednesday March 20th)

Best Days: Today Mid Coast, tomorrow morning South Coast and Mid Coast for the keen, Sunday for the keen South Coast, Monday morning South Coast, Tuesday morning South Coast

Features of the Forecast (tl;dr)

• Easing W/SW swell over the comins days
• Moderate sized, reinforcing mid-period S/SW swell tomorrow, easing a touch Fri and coming back up again Sat/Sun
• Moderate E/NE-NE tending S/SE winds tomorrow, light-mod S/SE Fri, freshening
• Fresh S/SE winds Sat, moderate S/SW Sun
• Moderate sized mid-period S/SW swell Mon AM with N/NW tending S/SE winds
• Larger S/SW groundswell arriving late in the day Mon, peaking early Tue and easing
• N/NE tending S/SE winds Tue, S/SE-SE Wed, Thu and Fri

Recap

Yesterday started small and clean down South with 1-2ft sets under a W/NW breeze, tiny and onshore across the Mid Coast. Into the afternoon a mix of new W/SW groundswell and localised windswell built, but with less than ideal winds.

Today, the swell is peaking with semi-clean 2ft+ waves on the Mid Coast that have improved from dawn, poor down South with a strong S'ly breeze.

Decent sized sets in the gulf

This week and next (Mar 21 - 29)

Looking at the end of the week, and today's peak in W/SW swell energy will ease, though slowed by some reinforcing mid-period S/SW energy across the South Coast.

Tomorrow morning will be the pick though far from perfect as winds shift E/NE-NE during the morning along with surf to 3ft+ across Middleton. The Mid will be clean but likely easing from 1.5ft.

Come Friday, 3ft surf should persist across Middleton but with a less favourable, light to moderate S/SE breeze. The Mid Coast will be back to 1ft max and only for beginners.

As touched on in Monday's notes, the weekend should see some new mid-period S/SW swell filling in, generated by a relatively weak but healthy polar frontal progression, moving under the country over the coming days.

This should boost Middleton back to 3ft+ through Saturday, similar Sunday with the Mid Coast coming in tiny.

Unfortunately winds will remain onshore and fresh from the S/SE on Saturday, creating poor conditions with slightly more workable, moderate S/SW winds on Sunday.

Of greater importance is the large S/SW groundswell due into later Monday/Tuesday morning across the state.

The source will be a strong polar low that's forecast to form on the tail of the activity moving through this week. The low isn't as well structured as forecast Monday, but it will be moving on top of an active sea state.

A slow moving fetch of W'ly tending W/SW gales projecting through our southern swell window should produce a large S/SW groundswell that's due to kick later Monday, peak overnight and ease through Tuesday.

Sets to 6ft are due late Monday and more so Tuesday morning, easing steadily through the day, and then down further from 3-4ft on Wednesday morning. The Mid Coast isn't expected to see much size, topping out at 1ft.

Conditions look good each morning with this swell, light N/NW ahead of S/SE sea breezes across the South Coast Monday and N/NE tending S/SE on Tuesday as a trough pushes through.

Moving into the middle to end of the week, winds look generally poor Wednesday and fresh SE-S/SE, possibly lighter on Thursday/Friday but still onshore. The weekend should provie cleaner conditions with some small-moderate sized pulses of SW groundswell but we'll review this Friday.