South Australian forecast by Craig Brokensha (issued Monday February 17th)

Best Days: Today South Coast, Mid Coast for the desperate Wednesday, South Coast Friday morning and Saturday morning

Features of the Forecast (tl;dr)

• Smaller tomorrow AM ahead of an new, small, inconsistent W/SW groundswell into the late PM
• Mix of inconsistent W/SW groundswell and better SW swell Wed, easing Thu
• Mod-fresh S/SE winds tomorrow, strengthening out of the S/SE through the day
• Fresh SE tending S/SE winds Wed
• Moderate E/SE winds Thu AM, freshening from the S/SE
• Small-mod sized, mid-period S/SW swell for Fri and Sat AM, then easing
• N/NE-NE winds Fri AM ahead of E/SE sea breezes
• Strengthening N-N/NW winds Sat ahead of a late, strong W/SW change
• Large mix of W/SW swells building later Sun, peaking Mon
• Strong SW tending weaker S winds Sun, possibly variable Mon AM

Recap

The weekend was a bit hit and miss with workable waves on the Mid Coast for the keen on Saturday with a lumpy, easing 1-2ft of swell, cleaner yesterday but tiny.

The South Coast was a mess on Saturday with a bit of size, lumpy and improving yesterday as onshore winds backed off and shifted more easterly as the swell remained solid.

Today is the pick though with cleaner conditions and easing sets from 3ft+ down South, tiny inside the gulf.

Good conditions this morning

This week and weekend (Feb 18 - 23)

Make the most of today down South, as a trough will bring a strong S’ly change this evening with moderate to fresh S/SE winds left in the wake tomorrow morning, strengthening through the day.

The swell will reach a low point tomorrow morning but we should see some inconsistent W/SW groundswell arriving into the late afternoon, peaking Wednesday mixed in with some better SW energy.

The source of tomorrow afternoon/evening’s increase in small W/SW groundswell and Wednesday’s better SW energy was a strong low that strengthened near the Heard Island region late last week as the remnants of severe Tropical Cyclone Vince drifted south into the westerly storm track.

An initial fetch of less than favourable aligned winds around the low proper will bring later tomorrow’s swell which should build to 1.5ft on the Mid Coast, holding Wednesday while a better aligned fetch was generated on the polar shelf, south of Western Australia on the weekend, producing a bigger, more consistent SW and better swell for the South Coast to 3-4ft off Middleton.

Unfortunately fresh SE winds will only favour the Mid Coast, with poor conditions down South while a slight improvement is likely down South Thursday as winds shift moderate E/SE through the morning along with easing 3ft sets.

It won’t be until Friday that we see a stubborn high pressure system in the Bight move further east, allowing winds to swing N/NE-NE through the morning. This will clean up most spots and there should be some fun mid-period S/SW swell in the mix, similar Saturday morning owing to persistent but weak polar fronts passing under the country today and tomorrow.

Middleton should come in at 2-3ft on Friday and Saturday morning, then easing with tiny 0.5-1ft waves inside the gulf.

Winds look to remain offshore until about early afternoon ahead of E/SE sea breezes, with Saturday seeing strengthening N tending N/NW winds ahead of a late W/SW change.

Now, this change will be associated with a possibly significant low moving in from the west, spawning to the south-west of Western Australia. The exact position, strength and timing are still moving around but regardless we’re expected to see a strong low generating large mix of W/SW swells for Sunday afternoon and Monday, along with gusty winds out of the south-western quadrant, possibly backing off through Monday. More on this Wednesday and Friday.