Indian Ocean Basin analysis by Craig Brokensha (issued Tuesday 11th February)

This week through next (Feb 12 - 21)

Late last week’s mix of swells eased back into the weekend, with an acute S’ly groundswell otherwise boosting wave heights across selected spots.

We’ve also seen poor levels of localised windswell thanks to strengthening westerly winds across the region (feeding into a tropical depression) and this will persist over the coming days but slowly weaken as winds also slowly abate Thursday but more so Friday onwards.

Groundswell wise there’s nothing of significance due this week (apart from a small background swell Friday), with mid-period S/SW-SW swell energy spreading off weak fetches sitting to the west of Western Australia.

Size wise it’s a bit of a guestimate but it only looks to come in around the small to moderate size range.

Otherwise we look at mid-late next week when we should finally see some better S/SW groundswell impacting the region.

The source will be of tropical origins, with Tropical Cyclone Vince which is currently in the middle of the Indian Ocean expected to weaken and track south over the coming days before being absorbed into the westerly storm track.

This will likely result in the rapid deepening and expansion of a low pressure system to the south-west of Western Australia, with a great fetch of severe-gale to storm-force SW winds due to generate a moderate to large S/SW groundswell for mid-late next week.

It’s due to build strongly Wednesday afternoon and offer the most size later if not into Thursday before easing Friday. Winds look variable and favourable from the weekend, but more on this in the next update.

In the Mentawais, pressure gradients have relaxed locally (bringing variable winds) thanks to Tropical Cyclone Taliah moving further to the west, but we’re still seeing great, swell producing gales on her northern flank generating moderate + levels of mid-period SW swell for the coming days as winds take a S/SE-SE tendency.

As Taliah weakens from tomorrow, the swell will fade later week, with us then looking at the S’ly groundswell from the strong polar low mid-late next week. This only looks moderate in size but we’ll review this Thursday.

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Maldives:

SE trade-swell should be muscling up today across the region, mixed in with some distant S/SW groundswell, with the SE energy produced by the south-western flank of Tropical Cyclone Taliah.

This swell should persist all week thanks to the slow moving and persistent nature of Taliah, tending more S/SE in direction through the weekend and then possibly easing next week owing to Taliah moving further west and then breaking down later this week. EC has it lingering a touch longer, bringing one final additional pulse of size.

Otherwise a healthy frontal progression below South Africa should generate some fun sized groundswell later next week. More on this Thursday.

Eastern Indonesia:

Low quality W’ly swell for the coming days, mixed in with mid-period S/SW-SW energy either side of 4ft.

Small, inconsistent SW groundswell for Friday to 4ft+.

Mod-large S/SW groundswell building next Wednesday afternoon to 6ft+ across exposed breaks, possibly holding a similar size Thursday morning, then easing.

Strong W/NW-W winds for the coming days, abating slowly later week out of the W/NW but more so on the weekend while tending more NW and then variable.

Uluwatu 16-day Forecast Graph/WAMs

Western Indonesia/Mentawais/South Sumatra:

Moderate + sized mid-period SW swell for the coming days, easing from later week.

Small, inconsistent SW groundswell Friday to 3-5ft.

Moderate sized S’ly groundswell for later next Wednesday and Thursday to 4-5ft+ across exposed breaks.

Variable winds, tending S/SE-SE from Thursday, more variable into the weekend and tending NW mid-late next week.

Mentawai 16-day Forecast Graph/WAMs

Maldives:

Mix of S/SW groundswell and mid-period SE swell for the coming days to 4ft across the southern atolls, 3-4ft central locations.

SE tending S/SE swell strengthening into the weekend to 4ft+ across central locations, possibly persisting into early-mid next week.

Mod-fresh E/NE winds across northern locations, easing over the coming days with lighter N winds to the south. Light to moderate N/NE-NE winds through the weekend and next week, more N’th to the south.