Western Australia Surf Forecast by Craig Brokensha (issued Wednesday August 4th)

Best Days: Tomorrow, Friday selected spots, Saturday selected spots, next Thursday and Friday

Features of the Forecast (tl;dr)

• New SW groundswell tomorrow with E/NE tending N/NE and then variable winds
• Stronger SW groundswell Fri with fresh NE tending weaker N winds
• Easing swell Sat with strong N/NE winds
• Stormy, onshore surf building Mon, peaking Tue, easing Wed with strong-gale force winds Mon, easing back to strong Tue/Wed
• Variable winds Thu AM with easing W/SW swell, cleaner but smaller Fri

Recap

Great waves across Perth and Mandurah yesterday with light winds, clean conditions and 2-3ft sets, easing through the day and back to a smaller 1-2ft today. The South West saw winds ease but remain moderate onshore yesterday, with OK waves for the keen through the day. Today is much cleaner and a fun 4-5ft on the sets.

This week and next (Aug 5 - 13)

We've got a couple of fun days surf coming up before winds swing back onshore into the weekend, ahead of an XL, onshore swell early-mid next week.

Looking at tomorrow and we should see the first pulse of two new SW groundswells due into the end of the week, both generated by pre-frontal W/NW gales pushing east-southeast through our swell window.

Tomorrow's will be the smallest but good sets to 5-6ft are due across Margs, 2ft in Mandurah on the sets and 1-2ft across Perth. Winds look favourable all day and light E/NE, shifting N/NE through the day and variable into the late afternoon.

The secondary stronger pulse of groundswell for Friday should see better 6-8ft sets across the South West swell magnets, 2ft+ in Mandurah and 2ft across Perth. Winds will be best early and fresh from the NE, swinging more N'ly through the day and easing later, favouring northern corners.

These northerly winds will be ahead of a trough, with strong N/NE winds favouring selected spots early Saturday as Friday's swell eases, becoming even stronger into the afternoon.

The trough will move through Sunday bringing a W/NW change which will strengthen from the NW through the day as a significant polar frontal progression starts pushing up from the south-west.

This progression will be a multi-threaded one, with three back to back storms due to fire up and towards us starting from Friday.

The first will originate from west of the Heard Island region, projecting a slow moving fetch of gale to severe-gale SW winds towards us, weakening once pushing through on Monday but with strength still.

This will then be followed closely behind by a stronger front, generating severe-gale SW winds while projecting up and into the state on Monday evening and Tuesday. A third weaker front is then due to follow Thursday.

Size wise, we'll be looking at large, stormy, mid-period surf building Monday with strong to gale-force W/NW tending W/SW winds, with the groundswell filling in from the first front Tuesday morning as winds ease back to strong and out of the W/SW. The secondary front will bring an XL increase in swell into the afternoon and evening, with an easing trend Wednesday as winds persist from the W/SW and with strength.

Looking at the expected size and the South West should reach 15-20ft with 4-6ft waves in Mandurah, 3-5ft across Perth but it's a moot point with the stormy conditions.

Thursday actually looks fairly decent as a high moves in, bringing light, variable winds that look to tend NE in the morning with moderate-large levels of leftover swell. More on this in Friday's update.