Western Australia Surf Forecast by Steve Shearer (issued Mon March 20th)

Features of the Forecast (tl;dr)

•  S/SW groundswell easing slowly Mon
• Gusty E/SE tending E/NE-E winds, then variable ahead of late sea breezes
• Easing swell Mon with moderate ESE-SE winds
• Moderate SW pulse Tues PM/ holding Wed AM with ESE-SE winds
• SE winds most of next week with another pulse Fri
• Moderate reinforcing SW swells this weekend with S’ly winds

Recap 

Small surf Sat didn’t exceed 3ft in the SW Corner with tiny waves elsewhere. Sun saw a solid groundswell fill in to 5-6ft with some bigger sets and offshore winds, smaller 2ft in Mandurah, 1-2ft in Perth. Today has seen using 3-5ft surf in the SW corner, smaller 1-2ft in Mandurah and 1-1.5ft in Perth under offshore winds and a’noon sea breezes.

This week and next week (Mar 21 - 31)

No great change to this week’s f/cast. High pressure slips under the state, becomes slow moving and maintains a SE flow for most of the week, tending SSW/S from Fri into Sat before tending SE again into early next week. This “stuck” synoptic pattern will favour semi-protected waves in the SW under a regime of small SW pulses this week, generated by a zonal suppressed storm track, augmented by some smaller, long range WSW swell generated in the far western Indian Ocean.

Expect a bottoming out in size through tomorrow with just small 3ft sets in the SW, tiny north of Bunbury and clean-ish conditions early under ESE-SE winds before S’ly seabreezes. Long range WSW swell should offer some inconsistent 3-5ft sets later in the a’noon. 

Closer range SW swell then overlaps the long range source Wed with size to 3-5ft in the SW, 2ft in Mandurah and 1-1.5ft in Perth. Similar ESE-SE winds tending to seabreezes favour semi-protected spots and reefs.

Similar size and conditions Thurs, with slightly less juice and more inconsistency.

A deep polar tracking just above the ice shelf reaches peak intensity through 100E later Tues/Wed (see below) producing a pulse of SW/SSW swell arriving Fri with size building to an inconsistent 3-5ft in the SW, smaller 1-2ft in Mandurah and 1ft in Perth due to the unfavourable S angled swell direction. Winds are likely to tend more S’ly Fri but the jury is still out as EC model still suggests an ESE-SE flow. We’ll fine tune on Wed.

We’ll see a slow easing in size over the weekend as the long zonal trailing fetch behind the polar low maintains SW-SSW swell in the 3-4ft range Sat and Sun, with S’ly winds.

Into next week and the zonal, suppressed storm track looks to break down but an initial low pressure disturbance in Madagascan longitudes is better aimed at Indonesia/Maldives with only small W/SW swell expected mid/next week.

Following disturbances look to be better positioned for the WA swell window but they are right on the edge of model runs so we’ll see how they play out as we get closer to the events and with more confidence in model runs.

Check back Wed for the latest.