West Australian Surf Forecast by Guy Dixon (issued Wednesday 18th May)

Best Days: Thursday morning.

Recap: 

There has been no shortage of surf across the South West over the last couple of days, with sets in the 6-8ft range on Tuesday, kicking to a solid 8ft+, with the odd bigger set in the mix. Metro beaches increased from the 2-3ft range on Tuesday to around 3ft this morning, easing slightly during the afternoon.

Winds have been an issue across the South West under a persistent onshore flow, despite being light today. Further north, this has been less of an issue, particularly in the morning under a light offshore breeze.

This week (Thursday 19th - Friday 20th) and this weekend (Saturday 21st - Sunday 22nd):

Today’s solid southwesterly groundswell will ease progressively from the 6ft range on Thursday across the South West, further from the 3-5ft range on Friday. Metro beaches will also fade from the 2ft range on Thursday, becoming small on Friday morning.

Conditions are looking workable on Thursday, particularly across the metro beaches under an easterly breeze. The South West should see a light east/northeasterly breeze during the morning before giving way to a seabreeze later.

Friday is looking less fortunate, with a brief window of opportunity in the morning along the metro beaches, before increasing from the northwest. The South West is likely to be under an increasing northwesterly flow from mid-morning.

A polar front looks to push northward through the southwestern swell window west of the Heard Island region on Thursday and into Friday, steering a broad but slightly disjointed southwesterly captured fetch towards WA’s southwest.

As this system develops, it should gain structure with fetches of around 35-45kts, although the slingshotting motion will be the most effective feature. We should see a strong groundswell due to build late on Friday afternoon to the 6ft range, more so on Saturday with sets up to 10-12ft. Perth should gain around 3-4ft off this system.

An element of this will also be local windswell as these fetches look to push right into the coast, which unfortunately will have a severe impact on wave quality.

Southwesterly trailing fetches in the wake of this system are likely to slow an otherwise easing trend on Sunday. Sets should fade gradually from the 8-10ft range.

Conditions will be woeful under a fresh-strong southwesterly airflow, easing marginally into Sunday.

Next week (Monday 23rd onward):

Distant background energy looks to be the most substantial source of swell during the early stages of next week, with a developing low looking to near the coast on late Tuesday evening. 

Northwesterly fetches along the northern and eastern quadrants of this system may whip up a windswell for Wednesday although with poor quality due to gusty onshore winds.

More detail on Friday.