Western Australia Surf Forecast by Craig Brokensha (issued Wednesday 14th August)

Best Days: All locations tomorrow morning (keen surfers in the South West), Saturday protected spots, Sunday all locations, early Monday all locations

Recap

Poor onshore waves across all locations yesterday morning, with the swell building into the afternoon but coming in best this morning. Mandurah and Perth were best with light winds and sets to 3ft, 8ft+ in the South West but onshore.

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This week and weekend (Aug 15 – 18)

Today's swell will ease back through tomorrow and we should see more variable winds across the South West with better but not the cleanest conditions, owing to onshore winds sitting just offshore. Perth and Mandurah will be better with light offshore winds and size wise, we'll be looking at dropping sets from 2-3ft in Mandurah, 2ft+ in Perth and 6-8ft in the South West.

Friday will be a lay day as a strengthening frontal system moves in bringing strong NW winds (N/NW early to the north) strengthening further into the afternoon out of the W/NW.

This will kick up a building windswell across all locations through the day ahead of a larger W/SW groundswell on Saturday and then large follow up S/SW groundswell.

The size of both of these swells has been upgraded since Monday with the strength and longevity of a strong mid-latitude frontal system moving in through the southern Indian Ocean being better. This and also a polar fetch of severe-gale S/SW winds at the base of the progression will generate a stronger, long-period S/SW for Sunday.

Size wise, Margs looks to come in at 10ft+ on Saturday, 4ft in Mandurah and 3-4ft in Perth with a strong but easing S/SW breeze, possibly a touch more S'ly through the morning.

Sunday looks much better with the W/SW swell easing and the S/SW groundswell filling in during the afternoon, kicking to 10-12ft across the South West magnets, holding 3ft+ in Mandurah and 2-3ft in Perth.

Conditions are looking great with a light E/SE offshore across Perth and Mandurah with Margs improving with a S/SE tending variable wind ahead of sea breezes.

Monday looks fun with the S/SW groundswell on the ease with E/NE offshore winds across all locations, tending NW into the afternoon.

Moving into next week and a large long-period W/SW groundswell is still on the cards, generated by a vigorous polar frontal progression firing up under the influence of a strong node of the Long Wave Trough developing in the Indian Ocean.

An initial tight low will generate a fetch of severe-gale W/SW winds, followed closely by a stronger and broadening storm, producing a fetch of severe-gale to storm-force W/SW winds while moving east.

Two large, long-period W/SW groundswells are due, the first building Tuesday ahead of the larger and more consistent swell Wednesday, coming in around 12ft+ across the South West, 3-4ft in Mandurah and 3ft in Perth with winds out of the northern quadrant. More on this Friday.