Swells ease a notch but more windows of good winds as storminess gradually abates in the Indian Ocean

Steve Shearer picture
Steve Shearer (freeride76)

Western Australian Surf Forecast by Steve Shearer (issued Wed September 20th)

Features of the Forecast (tl;dr)

  • Shift to more S’ly winds from Wed, tending E’ly Thurs/Fri plenty of surf
  • Super long period W/SW swell Thurs/peaking Fri expect long waits for sets
  • Swell building Sat with onshore winds, peaking Sun with a window of offshore winds
  • Offshore winds possible Mon AM with solid surf
  • More solid surf in the medium term with brief windows of clean conditions in a general onshore flow


Lots of size and onshore winds yesterday with around 8ft of swell between the Capes, 2-3ft at Perth/Mandurah and fresh onshore SW winds. Today has seen much lighter winds with a window of E/SE-SE winds offering the cleanest conditions for a while before light S’lies kicked in. Size was still in the 6ft range on the sets down south, 2ft in Perth/Mandurah.

Clean with some solid sets

This week and next week (Sep 20 - 29)

We’re on track for reduced storminess in the short/medium term with the very active late season Indian Ocean storm track starting to settle down a few notches (still active though) and some better quality windows of light or offshore winds on track for SWWA.

This includes the short term with high pressure under the state bringing a true offshore flow through the morning, tending light N’ly in the a’noon. Expect surf in the 6ft range from the SW (smaller 2-3ft in Perth/Mandurah), with some super long period forerunners from the humongous African storm arriving through the day- likely subordinate in size (4-5ft) to the main swell source but packing some punch. 

Long range, long period swell then peaks Fri with sets to 5-6ft, although very inconsistent. Again, closer range SW swell to 4-6ft will be dominant. Expect a light SE-S/SE flow early before winds tend light S’ly through the day as a west coast trough moves inland and a weak high pressure ridge establishes.

This holds winds from the southern quarter Sat, before they shift more favourably to the E/SE-SE on Sun as the high moves E.

New SW swell starts to build in Sat a’noon from a low tracking NE of Heard Island today. Expect some 6ft sets in the a’noon.

That swell will be in the water Sun morning with offshore winds and still on the build with 8ft sets likely by lunch-time, smaller 2-3ft in Perth/Mandurah. 

Into next week and Mon morning looks great with offshore winds and heaps of leftover SW swell still offering 6ft+ sets before easing. 

A series of mid-sized disturbances spaced around a day apart tracking across the Indian Ocean over the weekend and early next week (see below) look to supply plenty of moderate SW-W/SW swell from mid week. We’ll likely see a low point Tues before swells climb back into the 5-6ft range from Wed. At this point we should see some favourable offshore winds Wed and re-establishing Fri as high pressure moves underneath the state.

A slow, slow wind down from a late season maxima in storm activity looks likely going into the medium term, with more windows of favourable wind for SWWA.

Check back Fri and we’ll drill down into those details.


PKsswellnet's picture
PKsswellnet's picture
PKsswellnet Friday, 22 Sep 2023 at 1:21pm

Hey Steve
thanks for the foecaste and the heads up on the long period swell.
The waves were at my fav novelty spot at first light when I was getting into my wetty . Long long long walls, fast moving and easy paddle ins at what is usually a bit of a fat burger. Kinda of long waits between pulses of 3 wave sets. If I had just looked at the swell buoy wave heights would not have bothered going to that spot. So thanks a lot got some fun ones with very few out.