Western Australian Forecast by Craig Brokensha (issued Wednesday December 18th)

Best Days: Protected spots tomorrow, Friday morning, Saturday morning, Monday in the South West

Features of the Forecast (tl;dr)

• Large mix of groundswell and mid-period energy over the coming days (possibly undersized early tomorrow) with strong S/SE winds tomorrow (S/SW to the north in the PM)
• Gusty but easing SE-E/SE winds Fri ahead of sea breezes
• Smaller Sat with strong SE tending S/SE winds
• Small-mod sized, inconsistent W/SW groundswell building Sun, peaking overnight, easing Mon
• SE tending S/SE winds Sun, gusty E/NE-NE tending variable Mon
• Large mix of swells building Tue, peaking Wed with strong S/SW-SW winds

Recap

Monday’s large W/SW groundswell cleaned right up through yesterday with pumping waves from Margs to Perth and beyond with gusty offshore winds and solid surf. The South West eased steadily from the 10ft range, 3-4ft in Mandurah and 3ft across Perth.

This morning conditions were in stark contrast with half the size and onshore winds in the South West, cross-shore to the north but still 2-3ft.

One of the best days of the year

This week and weekend (Dec 19 - 22)

After dropping in power and size today, we’ve got our large, reinforcing W/SW groundswell for tomorrow, with it possibly being undersized at dawn (especially north in Perth and Mandurah) but otherwise come in at 8ft on the magnets with 2-3ft sets across Mandurah, 2ft+ in Perth.

A reinforcing but slightly weaker mid-period swell Friday looks to maintain similar sized waves before easing into the weekend.

Local winds will be tricky tomorrow and strong out of the S/SE, shifting S/SW across northern locations into the afternoon with Friday offering better SE-E/SE winds, strong early and then easing through the morning ahead of sea breezes.

Gusty SE winds are due into Saturday as the swell starts easing, with Sunday seeing a new, long-range W/SW groundswell building into the afternoon, peaking overnight and easing Monday.

The source was a strong low in our distant swell window to the south of South Africa, with infrequent 4-6ft waves due across the South West magnets, tiny to the north.

Strong SE tending S/SE winds are due on Sunday as the swell builds with gusty E/NE-NE winds on Monday, tending variable to the north while giving into a late S’ly change across southern locations.

Looking at Tuesday/Wednesday and our larger mix of swells from the W/SW and SW are on track, generated by another strong low that’s due to form south of South Africa today and will track east while weakening but broadening.

The initial severe-gale fetch will generate some inconsistent, long-range W/SW groundswell while the developments closer to us should produce larger, mid-period levels of SW swell.

Both should build Tuesday afternoon but peak Wednesday with the South West coming in around the 8ft range, 2-3ft Mandurah and 2ft+ Perth. Conditions and winds unfortunately look average with gusty S/SW-SW winds. More on this Friday.