Steadily easing size, ahead of another large swell next week

Western Australia Surf Forecast by Ben Matson (issued Wednesday 21st October)

Best Days: Thurs: pulsey, easing long period swells though windy at times, only small across metro coasts. Small in Margs Fri/Sat/Sun, tiny elsewhere. Tues PM onwards: extended run of large surf, biggest Wed/Thurs

Recap: Steadily easing surf through Tuesday saw favourable morning winds ahead of gusty S/SW breezes through the afternoon. Margaret River managed early 6ft+ sets but it was very small in Perth, and a little bigger in Mandurah. Similar conditions played out today (good morning winds, gusty southerlies through the afternoon) as a large long period swell produced 10ft sets across the Margaret River region, up to 3-4ft in Mandurah and 2-3ft in Perth.

Margs showing some size - and breaking quite wide - early this morning

Strong lines


Deceptive afternoon at Yalls as the wind picked up

This week (Oct 22 - 23)

*This week’s Forecaster Notes will be a little erratic as Craig’s on annual leave*

We’re now on the backside of this impressive run of groundswell, and easing swells are expected over the next few days.

Early Thursday may see a few leftover 6-8ft sets at a handful of swell magnets in the Margs region, but overall most locations will be down to 5-6ft and size should ease to 4-5ft throughout the day. 

A further easing to about 3-4ft is expected on Friday. We’re actually likely to see a small reinforcing S/SW pulse in the afternoon, from a modest polar low forming SW of the state today, but I don’t think it’ll add any more size to the pre-existing, easing swell. 

Across Perth and Mandurah coasts we’ll be back to the small stuff, just 1-2ft in Perth on Thursday morning and 2-3ft throughout Mandurah but dropping to borderline-surfable conditions for the afternoon and into Friday. Friday afternoon’s small reinforcing S/SW pulse won’t influence these coasts. 

As for conditions, expect moderate to fresh though easing SE winds on Thursday morning, becoming light to moderate by mid-late morning, but then perking up from the S/SE into the afternoon. A more E/SE thru’ E’ly flow is expected early Friday ahead of a similar afternoon S/SE thru’ S’ly breeze. 

This weekend (Oct 24 - 25)

Only small surf is expected this weekend. A small long range groundswell may provide inconsistent 3ft sets to exposed beaches in the lower SW both days, but it’ll be slow going. We probably won't pick up much surfable activity across the Mandurah and Perth stretches. 

Conditions look pretty good both days with moderate E’ly winds and afternoon sea breezes. 

If you’re desperate for a paddle, aim for the swell magnets down south.  

Next week (Oct 26 onwards)

Next week is still looking to be pretty large, thanks to an amplifying Long Wave Trough west of WA over the weekend.

The LWT will set up a conveyor belt of powerful fronts and lows through our mid range swell window, covering an impressive region of the southern Indian Ocean (check the fetch length, below). 

This will result in an extended period of elevated wave heights, from Tuesday afternoon thru’ Friday - though we’ll see the most size on Wednesday and Thursday. Max surf size should push up into the 12-15ft range at exposed locations in the Margs region, with bigger surf at offshore bombies. Perth should reach 3-5ft and we’ll see 4-6ft surf across the Mandurah stretch at the height of the event.

At this stage, the primary storm track is expected to be steered below the continent around the same time the swell reaches the mainland, which means local winds will be dictated by a (likely) heat low across the region. This has the potential for gusty S/SE winds at times but I think we’ll see pockets of offshore winds, much as we have this week. I’ll have a closer look on Friday.

See you then!


Redmond Clement's picture
Redmond Clement's picture
Redmond Clement commented Saturday, 24 Oct 2020 at 1:58pm

"There's more to life than surfing," an oblivious being said to me. Maybe but my life is meaningless and joyless without barrels.