Indian Ocean Basin analysis by Craig Brokensha (issued Thursday 3rd October)

This week through next (Oct 4 - 11)

A good sized, but inconsistent SW groundswell is in the water today, with it due to ease off into tomorrow morning ahead of our large increase in mid-period energy later tomorrow, ahead of the larger S’ly groundswell into Saturday.

The severe low linked to this swell has impacted Western Australia, with stormy XL surf breaking across the Margaret River region.

For Indonesia, satellite imagery has confirmed a great fetch of storm-force winds aimed northwards, and this will generate Saturday’s largest pulse of energy coming in at 8ft+ across most exposed breaks with 10ft cleanups likely.

The groundswell will come in smaller to the west and a little delayed in timing, filling in Sunday but very acutely south in direction. Ahead of this Saturday looks to provide larger, mid-period energy.

The swell should ease back steadily through Sunday and Monday, with a smaller, reinforcing mid-period S/SW swell due on Tuesday. This is being generated by weaker frontal activity on the backside of the current severe low, with the swell not really impacting locations to the west.

There’s also expected to be some inconsistent, better moderate sized SW groundswell in the mix Tuesday afternoon/Wednesday and this will favour western Indonesia better.

Later in the week some larger SW groundswell is due to move in, generated by a stream of healthy frontal systems from under South Africa from today. Multiple fetches of gales should produce some moderate to large sized SW groundswell, peaking through next Friday/Saturday. More on this Tuesday.

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Maldives: Some new S/SE trade-swell should be building across the region (peaking tomorrow afternoon through Saturday) thanks to an intensification of trades to our south and south-east. We’ve actually seen a Tropical Cyclone form, called Ancha, but it’s positioned too far west to generate any swell for the Maldives.

Instead the trade-swell will continue, slowly easing from Sunday and further next week as the trades dissolve.

We should see the trades re-intensify mid-week, generating building levels of SE trade-swell from later next week/weekend.

The low forming off Western Australia wasn’t too favourable for swell production across our regions, with some small, radially spreading energy due early next week.

Better pulses of S/SW groundswell will be in the water though from Sunday afternoon through early next week, with the stronger frontal progression firing up under South Africa due to Wednesday afternoon through the end of next week, moderate + in size.

Eastern Indonesia:

Moderate + sized, inconsistent SW groundswell to 6ft today, easing tomorrow morning.

Large mix of mid-period S/SW swell building later Friday, with a stronger S'ly groundswell in the mix for Saturday with sets to 8-10ft across exposed breaks.

Easing swell into Sunday, with some inconsistent background SW groundswell and mid-period S/SW swell energy Tuesday/Wednesday to 4-5ft+.

Mod-large sized SW groundswell for later next week in the 6ft+ range.

Weak E/SE-SE trades, variable offshore winds each morning.

Uluwatu 16-day Forecast Graph/WAMs

Western Indonesia/Mentawais/South Sumatra:

Easing S/SW groundswell today, smaller tomorrow morning.

Mod-large sized S/SW swell for on dark Friday, peaking Saturday to 6ft to occ 8ft across exposed breaks, with a reinforcing S'ly groundswell Sunday morning to 6ft+ or so, then easing.

Small-mod sized, inconsistent SW groundswell for Tuesday afternoon/Wednesday morning to 4-5ft+.

Mod-large sized SW groundswell for later next week in the 6ft+ range.

Variable winds, mod-fresh S/SE-SE early-mid next week.

Mentawai 16-day Forecast Graph/WAMs

Maldives:

Building S/SE trade-swell through today, strongest tomorrow afternoon/Saturday and to 4-5ft (smaller Male), easing slowly from Sunday, further into early-mid next week (bottoming out around 2ft+).

Mix of S/SW groundswell for Sunday afternoon and S/SE groundswell for Monday afternoon/Tuesday to 3-4ft on the southern atolls.

Moderate sized SE trade-swell building late next week into next weekend.

Moderate W winds tomorrow, freshening slowly on the weekend, then stronger into next week. Weaker SW winds to the south through the period.