Western Australian Surf Forecast by Steve Shearer (issued Wed September 13th)

Features of the Forecast (tl;dr)

• XL surf next Thu, easing  Fri with strong NW-W/NW winds, tending W/SW Fri
• Plenty of size Sat, building again Sun with onshore W-NW winds
• More large surf and onshore winds early next week
• Shift to more S’ly winds from Wed, possibly tending SE Thurs/Fri
• Smaller but still solid SW pulses Thurs/Fri, easing into the weekend 
• Storm track looks to fire up again next week

Recap

N’ly quarter winds shifted NNW and freshened yesterday in advance of a winter calibre storm. Size was in the 3-4ft range between the Capes. Strong to gale force NW winds today in a pre-frontal trough ahead of a front are making a mess of everywhere with stormy 8-10ft+ surf in the Margarets region, 4ft in Perth Mandurah and nowhere really to surf except a few novelty spots. More large onshore surf to come. 

Howling onshores and building storm surf

This week and next week (Sep 13 - 22)

No great change to the outlook this week and next. The current winter-calibre storm exits to the SE over the next 24 hrs with a high pressure to the north maintaining a ridge with the W’ly flow which continues across the SW of the state. An elevated high pressure belt over the state and high in Madagascan longitudes maintains a NE track of storms from Heard Island to WA longitudes. These storms will maintain elevated wave heights into mid next week, pulsing in the 6-10ft range into Tues with onshore winds. Surf will vary in the 2-4ft range in Perth Mandurah over this period with onshore winds.

The first sign of a pattern change is early/mid next week. An approaching high pressure ridge may bring a more S’ly flow opening up some more protected spots and possibly tending more SE in the Perth area. 

We may see a more widespread improvement of winds to the SE from Thurs as the high tracks under the state and a trough forms along the WA coast. 

A blocking high suppresses the storm track somewhat next week- at least in comparison this week- before breaking down, with a smaller swell regime likely from mid next week, although still maintaining size in the 6ft range in the SW, 2-3ft in Perth/Mandurah.

A monster storm in African longitudes Fri/Sat this week with seas in excess of 40ft sends ultra long period swell across the Indian Ocean, favouring Indonesia but with swell trains likely to hit WA early week of 25/9. 

A gale to severe gale force low tracking NE from Heard Island later next week will likely arrive the same time with size provisionally in the 6-8ft range. 

No doubt we will have some changes before then, but we’ve got a very active late season Indian Ocean storm track, that looks to take a quick breather next week before kicking off again. 

Lets see how it looks come Fri.

Seeya then.