Western Australian Forecast by Lorena Woortmann (issued Monday Jun 9)

Best Days: Perth and Mandurah on Wednesday, Thursday, maybe Friday morning and Saturday. 

Features of the Forecast

• Modest SW pulse on Mon PM but winds turn onshore
• Lay day on Tue with blown out easing swells
• Consistent large SW swell for Wed
• Good conditions at metro regions, blown out at Margs 
• Onshore winds at Margs from Wed-Sun
• Fun size and clean conditions at Perth and Mandurah on Thurs
• Building mid period WSW swell Thur PM/Fri
• Possible clean window at Perth on Fri AM 
• Size holds up on Sat with offshore breezes up north 
• New large groundswell Sun but onshore and mixed with localised short-period energy in Margs 

Recap

We had plenty of time for a few fun sessions over the weekend with an WSW swell to 8ft+ Sat morning in Margs, 3ft in Mandurah and smaller in Perth, slowly easing before a longer period WSW swell filled in with most of the size coming in overnight but still solid Sunday morning in the 6-8ft range in Margs and 3ft at metro regions.

A high pressure moved in and centred itself over WA keeping conditions fairly clean most of the time although there were fresher northerlies on Sat afternoon in Margs. There was still a fun size leftover this morning with clean conditions up and down the coast that are expected to deteriorate later and into the week. 

This week (Jun 9 - 13)

The surf eased today before a new WSW pulse arrives tomorrow afternoon and peaks Wednesday morning, generated by a strong and slow moving low over an active sea state to the east of Heard Island with sustained, severe-gale to storm-force winds aimed towards the region that was stronger than forecast Friday, hence showing an upgrade in sizes with 12-15ft in Margs, 3-5ft in Mandurah and 3ft at Perth, however conditions won't line up as well down south.

The strong low breaks down into a front and trough that will cross the state later today and tomorrow morning, hugging the southern WA/SA coasts, while on Thursday we have another front that will deepen southwards as it moves past WA.

In the short term we will see wind patterns changing due to these systems, driving fresh W’ly winds tomorrow tending more SW’ly down south, however Perth and Mandurah could see a morning of offshores with small leftover swell while we wait for the new WSW pulse.

By Wednesday conditions improve at the metro areas which are further from the low pressure influence, with offshores and a fun size from the WSW swell while Margs will still see a strong SW’ly flow and unmanageable surf easing in the afternoon.

The surf will drop on Thursday to 6ft+ at Margs in the morning but still uninviting as the second front moves in and draws N/NW’ly winds that strengthen out of the W/SW on Friday and persist through the weekend, bringing in a few messy days. 

Conditions will be more favourable up north Thursday morning with a small leftover surf that will continue to ease and light E’y breezes that freshen out of the N, before briefly backing off Friday early morning and going onshore in the afternoon.

Into the weekend we will see a mix of WSW mid-period and ground swells generated by a front moving past South Africa. The front strengthened today producing the long-period energy, then it will race ahead of itself as it moves eastwards and produces a mid-period pulse that arrives earlier on Thursday afternoon/Friday building to 3ft in Mandurah and 2ft at Perth.

This weekend (Jun 14 - 15)

On Saturday the size will hold up and it should be a good weekend at metro regions as winds go light offshore in the morning, tending moderate N into the afternoon. 

The groundswell arrives Sunday and eases into Monday with Margs seeing inconsistent 8ft WSW lines mixed with a building localised SSW low period swell and fresh onshore winds, while Perth and Mandurah will be in the 2-3ft range but not as clean as the days before as the winds shift onshore.