Western Australian Forecast by Craig Brokensha (issued Wednesday July 16th)

Best Days: Perth/Mandurah tomorrow morning and Saturday morning

Features of the Forecast (tl;dr)

• XL SW groundswell tomorrow with strengthening W/NW winds, lighter E/NE-NE to the north in the AM
• Reinforcing large to XL SW groundswell Fri with strong SW-S/SW winds (W-W/NW early to the north)
• Easing large surf Sat with variable offshore winds to the north, variable in the south, swinging NW
• Smaller Sun with strong N/NW winds (N/NE early to the north)
• Large, stormy SW swell Mon with strong SW winds

Recap

Perth offered really fun waves yesterday morning with a peaky 2-3ft of weakish swell under light winds, average and bumpy into the afternoon. Further south conditions were more wind affected and poor in the South West.

Today we’ve seen a cold front/trough bring a change and developing S/SE winds across the metro regions along with a large, building groundswell mixed in with lower period swells. The South West has remained poor with strong S/SW winds.

This week and weekend (Jul 17 - 20)

Our first pulse of large SW groundswell is in the water today but later into the afternoon an even bigger increase is due, holding tomorrow.

This has been generated by a great fetch of severe-gale W/SW winds to our south-west, with the strong low linked to it currently pushing further east, under the state.

XL 15ft surf is due in the South West with 3-5ft waves across Mandurah, 3ft to occasionally 4ft in Perth.

With the front clearing today we should see E/NE-NE winds across metro locations tomorrow morning, moderate N/NW into the afternoon with strengthening W/NW winds in the South West.

A slight drop in size is due on Friday, but a final frontal system generating severe-gale W/NW winds on the tail of today’s system will generate another large SW groundswell, maintaining 12-15ft waves in the South West, 4ft Mandurah and 3ft+ Perth.

Unfortunately our forecast onshore winds linked to the swell producing front pushing up and across the state are still on the cards, with strong SW-S/SW winds due in the South West, strong W-W/NW tending SW to the north.

Saturday is still the pick for a clean, solid wave with light, variable offshore winds due across Perth/Mandurah while Margs should also see variable winds but lumpy conditions thanks to onshore winds out to sea.

Easing surf from the 10ft range is likely in the South West, 3ft+ Mandurah and 2-3ft Perth.

Sunday looks smaller and strengthening N/NW winds will bring a rapid deterioration in conditions, with a window of fresh N/NE winds to the north.

The strengthening wind will be associated with a deep trough arriving out of the west, bringing a strong SW change Monday but poor quality swell thanks to the lack of gale-force winds.

A large, stormy increase in swell is still on the cards, easing Tuesday as the next frontal system moves in.

A constant stream of activity looks to persist into next week, resulting in generally average surf, with northerly locations not escaping the onshore blow. More on this Friday.