Western Australia Surf Forecast by Steve Shearer (issued Wed October 20th)

Best Days: Sat and Sun morning are the only windows of favourable winds amongst the onshore flow

Features of the Forecast (tl;dr)

• Residual SW swell Sat, with a window of good winds AM
• Small leftover Sun morning with good winds AM
• Another round of stormy, onshore surf likely from Tues next week as mid-latitude low approaches region
• Improving conditions possible from Fri, stay tuned for revisions

Recap

Solid storm surf eased through Thursday with 6-8ft surf in Margaret River, smaller 3ft in Perth and messy conditions under lingering WSW onshore flow.

New SW groundswell has come in strong today, rebuilding wave heights into the 8-10ft range in MR, smaller 3-4ft in Perth and Mandurah. More favourable S’ly winds allowed protected locations to come into play with some good options in the Bays.

A couple of windows are open on the weekend for cleaner surf. Details below.

This weekend and next week (Oct 23 - 31)

We’re on the backside of the current large swell event, with leftover SW swell slowly easing back through tomorrow, likely in the 5-6ft range early between the Cape’s, smaller 2-3ft in Mandurah and 2ft in Perth. A coastal trough brings a variable flow to most of the SW division through Saturday likely seeing a weak NE or ENE flow early, tending to weak onshore W’lies through the day. Best bet is early while the wind is offshore.

Sunday doesn’t look as great, with the trough moving inland and only a brief window of light offshore winds before onshore winds kick in. Expect mostly 3-4ft surf in the Margarets area, with a slight reinforcing pulse through the a’noon. Smaller 2ft surf in Mandurah and 1-2ft in Perth is expected.

Next week still looks like being marred by a constant onshore flow until Thursday as a node of the long wave trough directs weak fronts into the SW. A distant broad fetch of SW gales through today and into the weekend occupying a broad area between 70-90E generates reinforcing SW swell in the 13-14 second period band arriving Mon and boosting surf into the 4-5ft range at exposed breaks in Margaret River. The sustained nature of the fetch holds a pulsey swell at that size until Wed, but conditions are expected to be poor as a lingering, constant SW flow hammers surface conditions. You’ll have to hit up the protected Bays and sacrifice a lot of size. Expect 2-3ft surf in Mandurah and sub 2ft waves in Perth during this extended run of poor conditions. 

As mentioned on Wed, the large blocking high in the centre of the Indian Ocean and position of the long wave trough is unfavourable for the SW of the state as far as surf and conditions go. 

Into the medium term and it does look to break down next weekend as high pressure begins to slip under the state and potentially set up a ridge along the coast. That opens the door for some cleaner long range WSW swell before a more favourable pattern sets up first week in November.

With the long lead time, revisions are likely Mon, check back then and a have a great weekend.