Best days: Sunday, Tuesday AM in metro regions, Thursday AM in metro regions, Friday AM in metro regions.

Features of the forecast (tl;dr)

• Onshore tomorrow 
• Easing groundswell mixed with localised WSW energy
• Better winds on Sunday AM and fun surf 
• Reinforcing mid-period WSW pulse in the PM
• Light winds in the PM up north, onshore in Margs 
• Onshore on Monday
• Close-range WSW pulse Monday PM, but poor conditions 
• OK winds in Perth on Tue with easing swell 
• Building from Tues-Fri into XXL sizes 
• First groundswell on Tuesday PM 
• Easing Wednesday AM but with onshore winds across the coast
• XL SW groundswell Wednesday PM 
• Good winds on Thurs AM up north 
• XXL pulse Thursday PM/Friday AM 
• Light offshore winds up north on Friday AM 

Recap 

Yesterday, the surf slowly eased in size from Wednesday. Perth had clean, slow 2ft+ waves while Mandurah was at 2ft+ but lumpier. Margs has seen W/NW winds since Wednesday morning until this evening,

Today, Perth was the only place with clean conditions in the morning and 2ft waves on offer. The rest of the coast saw onshore winds all day that strengthened in the afternoon with the arrival of more frontal activity, coinciding with the arrival of a new swell.

This weekend 

We have a windy start of the weekend as the front that approached today keeps progressing east, sending onshore winds across the coast tomorrow. This afternoon’s groundswell will ease, mixed in with localised short period WSW energy added to the water by the local frontal activity. 

Sunday looks better than tomorrow as high pressure moves in between the frontal activity and winds back off. With the easing mixed swells, it should be a fun morning of surf with 2ft in Perth, 2ft+ in Mandurah and 6ft+ in Margs. 

The easing trend will be slowed down by the arrival of a reinforcing mid-period WSW pulse into the afternoon, produced today and tomorrow by the earlier stages of the front. Metro regions will still be fun with winds going light and variable in the afternoon, but more frontal activity approaching from the SW will deteriorate conditions around Margs by then. 

Next week

Next week we’ll see the surf progressively building in size with very strong frontal activity moving through the southern ocean and polar latitudes. Unfortunately for the South West, all these incoming systems are being projected northwards and get too close, with a long week of onshore winds ahead.

First, we’ll see the effects of a closer range fetch that develops Sunday afternoon producing a moderate mid-period WSW pulse that arrives Monday late morning/afternoon, sending sizes back to 2-3ft in Perth and 3ft in Mandurah.

While the arrival of this pulse will coincide with onshore winds up north, Tuesday morning should be OK with the easing swell and light NE winds. 

From then on, sizes will keep building until later in the week. The first SW groundswell due to arrive Tuesday afternoon was produced by a strong cold front to the south of South Africa that developed over the last couple of days. Margs should see it building to 8-10ft later in the day, with 3ft in Perth and 3-4ft in Mandurah. 

The forecast for Wednesday morning for metro regions has deteriorated and now we expect onshore winds as the front pushes further north as it moves towards SA. 

Later in the day, we have a second groundswell produced by a re-intensification of the frontal activity to the south-west of Heard Island with violent-storm force winds over an already active sea state. That system holds its strength as it moves east and will produce a significant swell that could be the biggest groundswell of the year so far, in the 20ft range for the South West. 

Thursday morning should be fun up north with light E/NE winds and 3-4ft in Perth and 4ft in Mandurah, before winds go onshore again. There is also a chance for an early window in Margs, although it will be bulky and tricky with onshore winds out to sea. 

Sizes will keep building into Thursday and Friday with a reinforcing swell built by a fetch of strong gales as the front moves east. For Margs, he peak of the swell will likely be later into Thursday, but the timing is still up for grabs. Perth and Mandurah could see the surf as big as it gets early on Friday, with Mandurah in the 5ft range and 4ft at Perth. With the winds looking light out of the E/NE, it should be an epic morning of surf up north. 

Although winds are persistently out of the western quadrant on the South West, novelty waves and the protected spots to the north will be breaking, so it is worth keeping an eye on that next week. 

We will provide an update on Monday about sizes and timing, depending on how these systems develop. Until then, have a great weekend!