South Australian Surf Forecast by Craig Brokensha (issued Monday March 13th)

Best Days: Tomorrow morning South Coast, Wednesday both coasts, Thursday South Coast, Friday morning South Coast, Saturday morning South Coast, Mid Coast Tuesday week

Features of the Forecast (tl;dr)

• Easing S'ly swell tomorrow with variable offshore winds, tending S/SE late AM and then S/SW
• Building W/SW and SW groundswells Wed, holding Thu AM
• Local offshore winds Wed AM ahead of weak sea breezes
• Fresh W/NW tending weaker W/SW winds Thu
• Easing surf Fri with light local offshore winds ahead of sea breezes
• Fun background SW swell Sat with W/NW tending SW winds
• Building mid-period SW swell Sun, holding Mon with slowly freshening S winds Sun, stronger S Mon

Recap

Fun waves across the South Coast early Saturday morning with variable winds and a drop in swell back to 2-3ft, while yesterday was less than favourable with similar amounts of swell but bumpier conditions.

This morning conditions have improved with a cross-offshore wind and peaky waves to 2ft+. A new pulse of S'ly swell is due to 3ft this afternoon but with sea breezes.

This week and weekend (Mar 14 - 19)

We've got a fun week of surf ahead with generally light, favourable morning winds and a good mix of swells from Wednesday.

Tomorrow will be smallest but still fun down South with this afternoon's final pulse of S'ly swell from the slow moving Southern Ocean gyre last week expected to ease from 2ft+ across Middleton.

Winds should be variable tending light offshore ahead of sea breezes later morning that will shift moderate S/SW during the afternoon.

Into Wednesday we're looking at a mix of building mid-period W/SW swell and stronger SW groundswell through the late afternoon, holding Thursday.

The source of these swells is a strengthening mid-latitude frontal system which formed west-southwest of Western Australia late last week, generating a fetch of strong W/SW winds. The frontal system is now deepening into a low off their south coast, with a great fetch of gale to severe-gale W/NW winds will be projected east-southeast through our western and then south-western swell windows.

The slow movement of the low will be advantageous for swell production, with a mix of W/SW swells due to build Wednesday ahead of swell more from the SW later in the day and more so Thursday.

The Mid Coast should build to 2ft on the sets through Wednesday afternoon with 4ft surf off Middleton. The Mid is likely to be a smaller and less consistent 1-2ft on Thursday but still 4ft off Middleton, with both easing Friday from 1ft+ and 3ft respectively.

Winds on Wednesday will be locally offshore, NE down South and E'ly on the Mid Coast ahead of weak afternoon sea breezes, providing fun options as the new swell builds.

Thursday now unfortunately looks average for the Mid Coast as a mid-latitude front pushes in, bringing fresh W'ly winds, best in protected spots down South and from the W/NW, shifting weaker W/SW into the afternoon.

No additional W'ly swell is due off this weak front above 1ft+ on the Mid Coast, with it weakening into Friday allowing winds to swing back locally offshore for both regions. The South Coast will be the pick with the easing swell energy.

Looking at Saturday and a secondary trough moving in from the west should bring favourable W/NW winds ahead of a W/SW-SW change that will then be followed by a ridge of high pressure. This will see S/SE winds develop into Sunday, strengthening into Monday.

Swell wise, some small reinforcing mid-period energy should maintain 2-3ft sets across Middleton Saturday, with 1ft sets on the Mid Coast, but come Sunday, some new mid-period SW swell is due to build, peaking Monday.

A broad, elongated Southern Ocean frontal progression developing east of the Heard Island region Wednesday evening will push slowly towards us through the end of the week and persist through the weekend. This will generate moderate levels of swell that should build to 3ft+ across Middleton Sunday afternoon and hold Monday, with 1ft+ sets on the Mid Coast.

We may see some reinforcing swell through Tuesday and Wednesday as winds slowly improve down South, shifting E on the former and light N on the later but we'll have to review this on Wednesday. The Mid Coast may see a bit more size as well but we'll have to confirm this Wednesday.