Best day: Tomorrow in Perth, Sunday, Wednesday AM in metro regions, Thursday AM in metro regions

Features of the forecast (tl;dr)

• Easing swell tomorrow, clean around metro regions, onshore in Margs
• SW Groundswell arriving Fri late AM with bad winds
• Onshore on Sat with mix of groundswell and localised WSW windswell
• Good window on Sunday AM with light winds holding into the PM up north, and easing mix of swells
• Reinforcing SW mid period pulse in the PM, onshore in Margs, OK up north
• Leftovers on Monday, clean in the AM at metro regions, onshore in Margs
• Back to back large SW pulses Tue PM and Wed PM
• Onshore on Tue PM
• Good winds up north Wed AM and Thurs AM, onshore in Margs

Recap

Yesterday we saw the large swell and windswell slowly easing through the day and Margs was still unmanegeable othern than novelty waves protected from the strong SW winds, while metro regions had clean conditions in the morning and late afternoon with the surf in the 3ft+ range across Perth, 4ft Mandurah. 

This morning it was still solid in Margs at 10ft with cross shore winds and much cleaner conditions than yesterday before the winds picked up again. Mandurah was also cleaner today with 3ft easing through the day and Perth had smaller sizes and a peaky broken up swell in the 2ft+ range.

This week (Jul 9-11)

Tomorrow the swell continues to ease and Perth will have clean leftovers easing from 2ft, while we see lumpy 2ft+ in Mandurah and straight onshores around Margs.

In the last notes we mentioned a SW mid-period pulse arriving Friday afternoon from a front developed to the east of Heard Island. This source has been upgraded with stronger winds today reaching storm-force at its core, producing a groundswell with longer periods that will travel faster and arrive earlier, more so Friday late morning.

This should build to 6-8ft around Margs, 2-3ft in Mandurah and 2ft+ in Perth, but the arrival will coincide with the a cold front projecting north and pushing against the state, bringing bad winds across the coast.

This weekend (Jul 12-13)

Into Saturday, we'll see that groundswell mixed with localised WSW swell from the cold front approaching the state, holding the surf at similar sizes but again with bad winds. The surf will ease from 8ft at Margs, 2-3ft in Mandurah and 2ft+ in Perth in the morning. 

Sunday is the day to mark on your calendar as this mix of swells will be slowly easing and now we have agreement between the models that conditions will improve in the morning. The cold front is now more likely to progress eastwards with a patch of high pressure bringing variable offshore winds over Margs in the morning, before seabreezes kick in early afternoon. Metro regions will see early moderate offshores going light and variable early afternoon with light to moderate seabreezes later in the day.

There is also a reinforcing W/SW pulse expected for the afternoon from the earlier stages of the cold front with a tight but well aimed fetch formed to the north-east of Heard Island. Unfortunately this will arrive with onshore winds in Margs, but metro regions should see the easing trend slowing down with this mid-period energy and OK conditions.

Next week (Jul 13 onwards)

Into next week we have more frontal activity moving in, and metro regions will still be clean with the remnants of the high pressure and small leftover waves. 

The incoming train of strenghtening frontal activity starts south of South Africa today, dips down into polar lattitudes and it could become stronger and stronger as is progresses east and pushes up. As the progression is forecasted now, it will produce two SW groundswells for mid next week, and depending on how it develops, we could see more size due later on. 

The first pulse is for Tuesday afternoon which will arrive in the 10ft range in the South West but with less consistency as it was created far away during the earlier stages of frontal activity near South Africa, and not very well aimed for the metro regions.

The second pulse is due Wednesday afternoon, although timing could still change until then. This swell will be bigger and more consistent, with a really strong fetch of violent storm force winds forming over the weekend to the south-east of Heard Island over an already active sea state. Sizes could be pushed up to the 12ft+ range in Margs, 3-4ft in Mandurah and 2-3ft in Perth. 

If the front holds its strength and pushes towards us, instead of splitting into different systems, Thursday could be even bigger, but check back on Friday to see how that is evolving.

This could be the biggest groundswell of the winter so far, but unfortunately winds are bad for Margs all week with all these frontal systems pushing up towards the state as they move east. Metro regions could see light offshore breezes on Tuesday morning, Wednesday morning and Thursday morning, but the surf won't be perfect with fresh onshore winds out to sea. 

We'll provide an update on how things progress on Friday. Until then, have a great week!