Best days: Thursday in Perth and Mandurah, Friday, Saturday. 

Features of the forecast (tl;dr)

• WSW swell easing tomorrow
• Clean in Perth all day and Mandurah in the morning, onshore in Margs
• Large WSW pulse arriving Thursday night / Friday AM
• Fun surf Friday and Saturday across the coast 
• Easing on Saturday at metro regions 
• Reinforcing SSW pulse for Margs on Saturday PM
• Easing into Sunday 
• Fresh ENE winds Sunday turning NE around Margs in the PM
• Freshening NE winds from Monday, going N on Tuesday at Margs
• Inconsistent moderate WSW groundswell for Monday
• Moderate SW swell on Tuesday 

Recap

Yesterday we saw the mid period energy dropping away and the arrival of a WSW groundswell maintaining the surf size through the day. 

Winds were light out of the E/ESE in Perth and SE/SSE in Mandurah until early afternoon with clean, peaky waves on offer.

Today Margs had a window of fresh offshore winds in the morning before shifting more northerly through the day, with the surf easing but still at the 6ft range. Perth also had clean waves in the morning with slow 2-3ft sets while Mandurah saw the NE winds earlier, deteriorating conditions and limiting options.

This week (Jun 25-27)

Tomorrow the WSW swell continues to drop, Perth will see 1-2ft leftovers and 2ft in Mandurah with light to moderate NE breezes in the morning as High Pressure sits over the country. 

Margs will be affected by the passage of a cold front in the Southern Ocean, with its northern tip crossing the South West and drawing NW winds over the coast. Mandurah will also see fresher winds out of the North feeding into that front into the afternoon. 

Tomorrow night we have the arrival of a groundswell produced by a powerful and slow moving system that pushed north into the Indian Ocean earlier in the week (satellite pass to the left), producing a strong WSW pulse that is well aimed for the whole coast. 

The system had a small downgrade with the overall strength of the progression a touch weaker, but it will still produce 10-12ft for Margs, 3-5ft for Mandurah and 3ft+ in Perth, peaking Friday morning with a slow easing trend.

Conditions are timed well for the arrival of this swell as high pressure moves in and we have a reprieve from all the frontal activity that has been bringing the onshore winds, with Friday and Saturday being really fun days across the coast and the best window to make the most out of the surf this week.

Perth and Mandurah will see light to moderate easterly winds most of the day with it tending light northerly in Mandurah into the afternoon. Margs has light and variable winds in the morning tending fresh ENE at lunch time before backing off again.

This weekend (Jun 28-29)

Saturday is another good day at all regions with the size slowly easing and swinging SW as the system maintained an active fetch as it moved closer to the coast. Winds will still be favourable with moderate E/ENE breezes at Margs going light and variable in the afternoon, and easterlies at the metro regions. 

Perth and Mandurah will see the surf easing, but Margs will receive a reinforcing SSW groundswell in the afternoon. The source is a polar front with storm force winds that moves below WA today and tomorrow morning. Due to its position, it will be out of the swell window for the metro regions, but it should keep sizes up to 8ft in the afternoon in Margs with a mix of the easing WSW swell and the new SSW pulse. 

Sizes back off on Sunday but the morning should still be fun with fresh ENE winds that NE around Margs into the afternoon.  

Next week (Jun 30-4) 

There is nothing major on the outlook for next week as off now as the Low Pressure System that could produce a large swell has downgraded and there is divergence in the models if it’ll even develop into a low. 

For Monday we have an inconsistent WSW groundswell produced by a fetch of gale force winds off a frontal system that is not very well aimed for the coast, arriving at a flukey 2-3ft in Mandurah, 2ft+ in Perth, and 6ft+ in Margs. This size is maintained through Tuesday but out of the SW, due to a pulse produced by a fetch of gales to the south-east of Heard Island. 

Wind wise, the northeasterlies start freshening from Monday feeding into a trough, and swing northerly on Tuesday, even going NW around Margs as the trough moves past the state.

On Wednesday there is a chance we might still see a quick pulse from the development of that Low, but considering the model divergence and how the system has downgraded since last week, we’re not too confident that one will come through. 

Later in the week and onwards we could see the return of frontal activity with strong onshore winds and localised wind swell. 

Until then, make the most of the weekend!