Western Australian Forecast by Craig Brokensha (issued Friday August 9th)

Best Days: Today Perth, selected spots Perth and Mandurah for the keen tomorrow morning

Features of the Forecast (tl;dr)

• Easing surf tomorrow with strong N/NW winds (weaker N/NE-NE in the AM across Perth and Mandurah)
• Large W'ly groundswell building Sun, with a secondary pulse Mon AM with mod-fresh W winds Sun, strengthening into the PM from the W/NW
• Strong W winds Mon, easing later
• Large W/SW swell for later Mon, peaking Tue, then easing for the rest of the week
• Fresh to strong W/NW-NW winds Tue, possibly variable early in Perth/Mandurah
• Strong W/NW winds Wednesday 

Recap

Perth offered a window of variable winds and cleaner conditions yesterday morning with easing surf from 3ft+, lighter onshore but still bumpy and to 4ft across Mandurah while Margs remained onshore.

The swell has eased off further this morning and winds have a touch more north in them with lumpy conditions in Perth, bumpy across Mandurah and still poor in the South West.

This weekend and next week (Aug 10 - 16)

The west swells/winds continue this period, and the reason is outlined in this article: Stratospheric Warming Event Comes Home To Roost

The current swell will continue to ease into tomorrow and strong N/NW winds will create poor conditions in the South West, slightly better and N/NE-NE across Perth and Mandurah during the morning with 2ft of swell.

Into Sunday, we’re expected to see some large new W’ly swell filling in, generated by a strong and northward protruding cold outbreak that’s currently west of us.

Fetches of gales are being projected through our western swell window and this will see two, back to back pulses of large swell generated, the first for Sunday afternoon with a secondary pulse for Monday morning.

The South West looks to come in around 10-12ft from these swells, 4ft Mandurah and 3ft+ Perth, while a third, trailing frontal system is due to move in on Sunday/Monday, producing a slightly larger pulse of swell for Monday afternoon and Tuesday. 10-12ft+ surf is due in the South West, 3-5ft Mandurah and 3-4ft Perth.

Looking at the local winds, and Sunday will see moderate to fresh W’ly winds, strengthening into the afternoon from the W/NW with Monday seeing strong W winds as the swell generating front moves across us.

There’s the possibility of winds going more variable across the metro regions on Tuesday morning, but otherwise we’ve got fresh to strong W/NW-NW winds due across all regions. Check back here Monday for a clearer idea.

Unfortunately winds will persist from the W/NW and strengthen on Wednesday as the size from Tuesday eases, smaller Thursday and Friday with W/SW-NW winds.

Longer term it looks like onshore winds will persist next weekend with another large to extra-large pulse of groundswell. More on this Monday. Have a great weekend!