Western Australian Surf Forecast (issued Mon 14th Apr)

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Craig started the topic in Monday, 14 Apr 2014 at 4:28pm

Western Australia Surf Forecast by Craig Brokensha (issued Monday 14th of April)

Best Days: Wednesday morning, Friday, Saturday morning, Sunday morning, Monday morning


The weekend started off slow with small amounts of swell and variable winds during the morning.

Sunday on the other hand saw them mix of new groundswells coming in way above expectations in the South West with an early rise in size to 5-6ft+, above the expected 3-4ft during the afternoon. This looks to have been the medium-range SW groundswell from a tight mid-latitude low coming in bigger than expected rather than the longer-range groundswell that's filled in today, keeping 6ft+ sets hitting the coast.

In any case this provided great waves for the final day of competition for the Margaret River Pro, while today good surf continued across most of the state with plenty of swell and morning offshores.

This week and weekend (Apr 14 – 18)

Tomorrow will be worth giving a miss as today's swells eases and an approaching cold front brings with it freshening onshore W/SW tending S/SW winds (that may be variable at dawn but only for a short period).

Tomorrow's front will be attached to a vigorous mid-latitude low pushing towards us, with a fetch of gale to severe-gale W/SW winds expected to be aimed into the South West of the state.

This should kick up a large W/SW swell for the South West on Wednesday, reaching 6-8ft, while Perth will see more SW in the direction and build to 2-3ft into the arvo. Only a late kick is expected around Gero ahead of a peak early Thursday to 3-5ft.

Winds Wednesday morning should go offshore from the SE, but afternoon sea breezes will spoil the new swell, while Thursday will see onshores from a vigorous front crossing the South West during early morning, with S/SE winds further north around Perth and Gero.

Of much greater importance is the large and powerful SW groundswell associated with Thursday morning's frontal system.

As touched on last update, this swell will be the biggest we've seen in months and winds are expected to co-operate as well.

The formation of this swell is thanks to a strong node of the Long Wave Trough amplifying just west of the Bight (pictured right), steering and supercharging a polar front from the Heard Island region right up towards us.

A broad and long-lived fetch of gale to severe-gale W/SW tending SW winds will be projected up towards us (pictured below right), producing a large, long-period and very powerful SW groundswell for Friday.

Size wise we're looking at 12-15ft waves in the South West, with larger sets at offshore bommies, while Perth should see 3-4ft waves at exposed spots, and Gero 6-8ft sets into the afternoon.

Winds should swing moderate offshore from the E/SE in the wake of Thursday's frontal passage creating excellent conditions for those looking to hunt down some very solid waves. S/SW sea breezes will then favour protected spots into the afternoon.

This weekend onwards (Apr 19 onwards)

Friday's swell should tail off into the weekend as SE winds favour slightly protected locations over more exposed locations.

A reinforcing SW groundswell is due on Sunday from a polar low firing up on the tail of the system generating Friday's swell but this system won't be anywhere near as strong or broad. Much smaller 6ft to occasionally 8ft sets are due in Margs Sunday morning, with 2ft+ sets in Perth and 3-4ft+ waves up at Gero as winds swing back to the E/SE during the morning.

Longer term there's nothing major on the cards with a slow drop in size expected through next week.