Mid later Friday/Saturday, South Coast Sunday
South Australian Forecast (issued Wednesday 18th March)
Best Days: Early tomorrow down South, later Friday on the Mid, both coasts Saturday morning, South Coast Sunday morning
Tiny building windswell across the Mid yesterday, and the South Coast was clean in protected locations but small with a freshening W/NW breeze.
Today a mix of inconsistent S/SW groundswell down South and a W/SW windswell across the Mid have provided a boost in sized and conditions are improving on the Mid as expected with winds tending more variable into this afternoon. The South Coast should also see winds tend more variable from the NW.
This week and weekend (Mar 19 - 22)
Both the S/SW groundswell seen down South and W/SW windswell on the Mid are expected to ease into tomorrow and the early will be the only decent window of good conditions down on the South Coast. Fresh N/NW winds at dawn will swing W/SW late morning but there won't be much size left from today with inconsistent 2ft sets at Middleton and 3ft bombs at Waits and Parsons.
Into Friday a large mix of W/SW and SW groundswell are due to fill in across both coasts, with the frontal system generating these swells currently sitting just south of WA.
This front will push through the Bight this evening while generating a broad and elongated fetch of W/SW gales in the Mid's swell window before re-intensifying just to our south-west tomorrow, aiming an additional fetch of severe-gale SW winds into the South Coast's swell window.
Both the W/SW and SW groundswells from this system are due to arrive around the same time, that being during Friday midday/early afternoon.
A solid kick to 3ft is due across the Mid on the sets into the afternoon/evening while the South Coast should pulse to 4-5ft at Middleton with 6ft+ sets at Waits on dark.
A peak in size is due overnight with the swell easing from 2ft to nearly 3ft Saturday morning across the Mid, while the South Coast should drop from 3-5ft at Middleton and 5-6ft at Waits.
Now, winds on Friday morning will be poor and fresh and gusty from the SW but a swing to S'ly breezes is due during the day, creating improving conditions on the Mid ahead of a late S/SE breeze into the evening.
Saturday morning will be great on the Mid with a fresh E/SE'ly, while the South Coast will be better but peaky and lumpy with an E/NE breeze through the morning before the S'ly kicks back in.
Sunday is the day to head down South though with offshore N/NE winds and a more manageable swell across the more exposed breaks, easing from 3ft at Middleton and 4-5ft at Waits and Parsons. The Mid will likely be tiny.
Monday onwards (Mar 18 onwards)
Into Monday we've got a mix of inconsistent but strong SW groundswell and junky windswell from a similar direction due.
During today an intense but small polar low is forecast to develop under the Heard Island region, producing a fetch of severe-gale to storm-force W'ly winds in our far swell window.
This low will then slow down but broaden a touch south-west of WA tomorrow resulting in the long-period but size-less swell to propagate towards us, arriving through Sunday afternoon/evening but with no major size.
A better and also inconsistent swell is due off the low once it slows down, arriving through Monday and building to 3-4ft at Middleton and 5ft+ at Waits through the day, but a strong onshore change will also kick up some junky windswell boosting wave heights into the afternoon.
The Mid Coast should see the windswell kicking to 2ft through the day but with no quality. More on this Friday though.