Western Australia Surf Forecast by Craig Brokensha (issued Wednesday 17th August)

Best Days: Perth Friday morning, Tuesday morning protected spots all regions

Recap

Good clean 2-3ft waves across Perth and Mandurah yesterday morning before the onshores kicked in, while Margs was also clean and around 6-8ft before the wind got stuck into it.

Today onshore winds and rain were up from dawn across all coasts with a building low quality stormy windswell.

This week and weekend (Aug 18 - 21)

This afternoon's increase in large stormy W/SW swell will swing more SW while easing through tomorrow as the tail end of the mid-latitude front pushing into us aims SW winds through our swell window.

Onshore SW tending S/SW winds are now due to persist across all coasts tomorrow (with no chance of a S/SE'ly around Perth) and the surf will be dropping from 6-8ft in the South West and 3ft around Perth.

Smaller surf is due into Friday and increasing W/NW winds will impact the South West, with an early E/NE'ly around Perth and smaller 1-2ft waves.

A small mid-period SW swell is due Saturday, generated by a weak fetch of pre-frontal W?NW winds moving through our swell window Thursday and Friday.

The South West is likely to hold around 4-5ft+ but with W/SW to S/SW winds. Perth isn't due to offer any real size with 1-1.5ft sets and an onshore change is due around dawn or just after.

Sunday will be cleaner around Perth with a variable breeze, but the swell tiny. Margs will continue to see poor conditions with an increasing W/NW breeze ahead of a SW change.

Next week onwards (Aug 22 onwards)

Behind the weak pre-frontal W/NW fetch, a much stronger and longer-lived frontal system is due to, developing under South Africa and traversing the whole southern Indian Ocean from early tomorrow morning through Sunday, before the remnants push up and into us Monday.

A large W/SW groundswell is expected off this system, building through Monday, peaking overnight and easing Tuesday.

Margs should build to the 10ft+ range later Monday and ease from 8-10ft+ Tuesday morning, with Perth seeing 2-3ft sets later in the day, easing from a similar size Tuesday.

Conditions will remain poor Monday with the front pushing into us, generating SW winds.

Tuesday should see S'ly winds across the South West, favouring protected spots, with S/SE winds around Perth and Mandurah. Let's confirm this Friday though.