Western Australia Surf Forecast by Craig Brokensha (issued Friday 20th April)

Best Days: Tuesday morning Perth and Mandurah, Wednesday morning Margs, Thursday morning all locations

Recap

Our W/SW swell due Wednesday took a while to get going but provided good fun waves across Perth and Mandurah yesterday to 2ft+ (onshore in the South Wets).

The swell is hanging in there this morning, though a touch smaller and light winds created favourable conditions again.

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This weekend and next week (Apr 21 - 27)

Later today we should start to see the long-period forerunners showing on the wave buoys across the state, linked to our large W/SW groundswell due tomorrow.

These forerunners will hardly have any size attached to them, with the bulk of the swell expected to fill in tomorrow and peak into the afternoon/evening.

There's been no change to the expected size with exposed breaks in the South West due to reach 10ft+ late tomorrow, with 3-4ft sets across Mandurah and 3ft in Perth by dark.

The swell should then ease slowly from 8-10ft across the South West Sunday morning, mixed in with some new mid-period and W/SW windswell from a couple of fronts firing up towards us today and through the weekend.

We can expect smaller surf than the long-period groundswell across the South West, but Perth and Mandurah are likely to hold in the 3ft range all day Sunday before easing slowly from a similar size Monday.

The South West will also continue to see mid-period junky W/SW energy as one of the fronts/lows stalls off our south-west Sunday, aiming strong W/SW winds into us and then moves east Monday.

Now, winds are still terrible with a strengthening N/NW breeze through tomorrow (likely N/NE early Perth/Mandurah but with no size in the morning).

Sunday will then see strong NW tending W/NW winds across all locations (likely reaching gale-force in the South West) and then W/SW winds Monday.

Tuesday should finally see light offshore winds kick back in across Perth and Mandurah with easing surf from the 2ft range, and lingering onshore across the South West.

So for the most part this whole swell event will be a write-off.

We then look towards our better SW groundswells due mid-week and next weekend.

A good slow moving polar frontal progression will develop in the Heard Island region tomorrow, with a good fetch of W/SW gales projected through our south-western swell window through until Tuesday next week.

The slow moving nature of these fetches will help amplify the open ocean sea state, with a large SW groundswell expected, building Wednesday to a peak later in the day. Margs should build steadily towards 6-8ft at swell magnets, with Mandurah kicking to 2-3ft later, and 2ft in Perth.

A slow drop in size is due Thursday from 6ft to possibly 8ft in the South West, 2-3ft in Mandurah and 2ft around Perth.

Conditions Wednesday morning as the swell builds will be clean with E'ly offshores ahead of afternoon sea breezes, great Thursday morning with E/SE offshores.

The secondary slightly bigger SW groundswell is still on track with a much stronger polar low forecast to generate severe-gale to storm-force winds in our south-western and southern swell windows, producing a large SW groundswell for Saturday though winds may be average. More on this Monday. Have a great weekend!