Best days: Saturday AM, Tuesday afternoon in metro regions, Wednesday in metro regions, Saturday in metro regions. 

Features of the forecast (tl;dr)

• Good conditions tomorrow AM 
• XXL stormy surf building from Sunday, peaking Monday with onshore winds
• Slow easing trend on Tue
• Onshore winds Tue in Margs 
• Improving in the PM around metro regions 
• Fun surf in Perth and Mandurah on Wed with easing swell and offshore winds
• Large in Margs and improving through the day, better at semi-protected spots
• Smaller on Thur and Fri with NE/NNE up north in the AM, deteriorating through the day 
• Onshore in Margs 
• New SW pulse arriving Fri PM / Sat AM better aimed at Margs but onshore 
• Better conditions up north in the AM 
• Deteriorating from Sunday

Recap

Yesterday morning Margs and Perth had an OK window in the early morning with leftover groundswell that deteriorated first in the South West and late morning in Perth, while Mandurah still had clean surf in the afternoon with a building, close-range W/NW swell.

Today we had clean conditions up north with the easing mix of localised swell while the South West was mostly blown out with the remnants of a front that moves past the state this afternoon.

This weekend (Jul 5-6)

Tomorrow morning we have a good window in Margs with a new inconsistent SW groundswell formed by a distant polar low south of Madagascar pushing the surf up to 6ft+ around Margs, 2ft in Mandurah and 1-2ft in Perth. The whole coast will see well groomed conditions as we have offshore winds through the night and light NNE breezes in the morning, but into the day we’ll see winds picking up, first in the South West and into the afternoon up north.

For the rest of the weekend things get a bit wild with strong onshore winds and large stormy surf building on Sunday as a strong front approaches the state from the south-west. 

Next week (Jul 7-11)

The frontal activity pushes against the coast on Monday and firstly we’ll see local stormy windswell in the morning with a SW groundswell arriving in the afternoon generated by the early stages of this system, mixed in with the localised short period energy. This should build up to 15ft around Margs, 4-5ft in Perth and 6ft in Mandurah with stormy conditions. 

The onshore winds persist on Tuesday but in the afternoon metro regions could see it going light S depending on the progression of the front, and we will have more certainty on that by Monday. The stormy swell will be on an easing trend that however that is slowed down by the arrival of a reinforcing pulse formed by a second strong front formed at the back of the system, which is better aimed for the South West than to regions up north. 

As the frontal progression moves towards SA and VIC, we have a ridge of high pressure over the state on Wednesday and that will bring improving conditions around metro regions as winds go offshore. Mandurah will have 4ft in the morning and 3ft in Perth, easing into the day.

Margs will still be 10ft+ and it could ease or stay at the 10ft range depending on how the storm develops, with large lumpy surf in the getting cleaner later in the morning and afternoon. Semi-protected spots will be the best filtering out the short period added by the southerly winds on Tuesday. 

The surf keeps dropping on Thursday with better winds up north out of the NE/NNE in the morning and deteriorating through the day, while the NW winds will be up early in the South West. 

Next weekend (Jul 12-13) 

The next pulse is due into Friday afternoon and Saturday morning from a polar front strengthening to the south-west of Heard Island on Tuesday, with strong gales producing a strong SW groundswell. 

Unfortunately, that will arrive with average winds around Margs while metro regions will only be getting 2ft from this source with OK conditions on Saturday morning as the high pressure moves over the country and more frontal activity approaches from Sunday with more onshore winds.