Western Australian Forecast by Craig Brokensha (issued Monday December 30th)

Best Days: Tomorrow morning, Wednesday morning, Thursday morning Perth and Mandurah

Features of the Forecast (tl;dr)

• Moderate + sized pulse of mid-period SW swell building later today, peaking tomorrow, easing tomorrow
• Large SW groundswell building Wednesday, peaking into the PM, easing slowly Thu
• Fresh E/SE-SE winds ahead of sea breezes tomorrow
• Moderate E/SE-SE winds ahead of sea breezes Wed
• Light to moderate W/SW winds Thu, freshening (variable in the morning across Perth/Mandurah)
• Smaller Fri with gusty S/SE tending strong S/SW-SW winds 
• Small-moderate sized mid-period swell Sat with strong but easing SE winds ahead of sea breezes
• Smaller Sun with S/SE winds

Recap

Saturday started small but some new swell built into the afternoon though yesterday offered the best of it with fun, cleanish 4-5ft waves across the South West, 2ft across Mandurah and small in Perth.

Today the surf was similar in size and a little peaky/not perfectly lined up across all locations but it’s gotten better through the morning. Some new swell is due into this afternoon but with strong sea breezes.

This week and weekend (Dec 31 - Jan 5)

The coming days look great for surf with strong pulses of swell due under favourable winds. 

Later today and tomorrow morning we’ll see a moderate + sized pulse of SW swell filling in across the state, generated by the first of a series of two lows moving in from the Heard Island region over the weekend.

The initial low generated fetches just below gale-force strength and we should see the swell coming in at 6ft to occasionally 8ft across the South West tomorrow morning with 2ft+ waves in Mandurah, 2ft across Perth.

A moderate to fresh E/SE-SE breeze will create clean conditions tomorrow morning ahead of strong sea breezes.

Into Wednesday our secondary pulse of stronger SW groundswell is due, generated by the second low that’s currently south-west of us.

Fetches of gale to severe-gale W/SW winds will weaken slowly through today with the swell due to build strongly through the day and reach 8-10ft in the South West during the day, 2-3ft Mandurah and 2ft+ Perth.

Winds look favourable again and moderate out of the E/SE-SE across the South West, straighter offshore to the north with strong sea breezes due into the afternoon.

As the swell eases Thursday winds are due to swing light onshore across all locations but Perth and Mandurah are likely to see morning variable winds with easing sets from 8ft across the South West, 2-3ft Mandurah with 2ft sets across Perth. Conditions will deteriorate as the day progresses thanks to strengthening W/SW tending SW winds, gusty S/SE tending strong S/SW-SW winds into Friday.

Come the weekend, one final pulse of mid-period SW swell is due into Saturday, generated by a strengthening low late in our swell window.

The low will spawn of a weak front, with fetches of strengthening W/SW winds firing up to our south-west, producing 4-6ft waves in the South West, 1-2ft Mandurah and tiny waves across Perth.

Strong but easing SE winds are due on Saturday ahead of sea breezes with easing surf under S/SE winds Sunday morning.

Longer term the outlook is much slower with nothing of substance due through next week as the Southern Ocean falls quiet, with weak tropical developments in the Indian Ocean.

Therefore make the most of the coming swell.