South Australian Forecast by Craig Brokensha (issued Monday April 21st)

Best Days: South Coast Wednesday morning and Thursday, Sunday South Coast

Features of the Forecast (tl;dr)

• Moderate sized S/SW groundswell building tomorrow, holding Wed AM, then easing
• Fresh SE tending S/SE winds tomorrow, N/NE-NE tending SE Wed
• Freshening N/NE tending N/NW-NW winds Thu
• Moderate sized, inconsistent SW groundswell building Fri, peaking in the PM, easing Sat
• Early W/NW tending tending strong S winds mid-AM Fri
• Fresh S/SE winds Sat
• Moderate sized mid-period SW swell building Sat, peaking overnight, easing Sun
• N/NW tending W/NW winds Sun
• Smaller Mon with gusty E/SE-SE winds

Recap

Friday’s swell eased off slowly all weekend and the South Coast was the pick Saturday with clean conditions and fun sized surf before winds strengthened later.

Yesterday was windy and doable in protected spots down South with building levels of S/SW swell from a low stalling just west of us while the Mid Coast saw a semi-stormy increase in localised swell.

Today the surf is still large and onshore down South with a little more favourable wind across the Mid Coast but with weak, easing surf from 1-2ft.

This week and weekend (Apr 22 - 27)

Looking at the week ahead and tomorrow will be a write-off ahead of better conditions into Wednesday and the end of the week.

The slow moving low linked to all the wind and swell through yesterday and today will continue moving east bringing fresh SE tending S/SE winds tomorrow before backing off and tending light N/NE-NE into Wednesday morning.

Swell wise, a good, new S/SW groundswell is due to build tomorrow and hold into Wednesday morning, generated by a strong polar low that formed south of the country yesterday.

The low generated a pre-frontal fetch of gale to severe-gale NW winds followed by post-frontal W’ly gales and with this we should see a good kick in size to the 4ft+ range across Middleton tomorrow afternoon, holding a similar size Wednesday before easing into the afternoon, further Thursday.

The Mid Coast isn’t likely to top 1ft thanks to the southerly direction of the swell and while Wednesday morning looks clean and sizey, Thursday is likely the standout under all day offshore N/NE tending N/NW-NW winds for the South Coast.

Into Friday, an inconsistent SW groundswell is due to fill in, peaking through the afternoon under early W/NW winds ahead of trough and strong S’ly change mid-morning.

The groundswell is being generated by a strong but thin polar low that’s currently just east of the Heard Island region. This should produce a fetch of severe-gale W’ly winds though due to the large distance between us and the coast, it’ll be very inconsistent. Middleton should build to 3ft+ into the afternoon with tiny waves across the Mid Coast, easing Saturday under weaker but persistent S/SE winds.

Sunday looks the pick as winds shift back to the N/NW ahead of another trough, shifting W/NW into the afternoon. Swell wise, some new mid-period SW swell is due to fill in Saturday, peaking later and then easing Sunday.

A flurry of relatively weak storms moving in from the south-west from Wednesday through the end of the week, will generate fetches of sub-gale-force winds, though we should still see moderate sized due into Saturday afternoon and Sunday morning to 4ft off Middleton, 1-1.5ft on the Mid Coast.

Those local winds will favour the Mid Coast Saturday (bumpy afternoon) with dawn Sunday possibly seeing variable winds before they go west of north.

A trough looks to bring E/SE-SE winds on Monday as the swell eases, but more on this Wednesday.