Indian Ocean Basin analysis by Craig Brokensha (issued Tuesday 17th September)

This week through next (Sep 18 - 27)

The swell is on a slow decline following the weekend’s and yesterday’s pulses of inconsistent and tricky S/SW groundswell.

The trend will continue down tomorrow morning but into the afternoon and more so Thursday for eastern Indonesia, a small but well angled mid-period SW swell is expected to show.

It won’t have any major size but will provide a fun increase in swell that’s worth making the most of before fading into the end of the week and weekend.

Unfortunately the rest of the outlook is unreliable thanks to us relying on S/SW swell energy spreading up raidally from a series of strong frontal systems pushing under Western Australia.

These will form late in our swell window and as a result will be inconsistent, very south in nature and flukey at best. The Mentawais will see less size and consistency again.

The first and best pulse is due to arrive Sunday, generated by a fetch of W/SW gales to the south-west of WA over the coming days.

This should build into the afternoon ahead of a peak Monday morning, then easing into the middle of the week.

It only looks moderate in size but worth making the most of with secondary pulses for later week due to come in smaller.

Longer term there are indications that we may see some better swell into the start of October but more on this Thursday.

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Maldives: A mix of easing SE trade-swell and S’ly swell energy is currently being seen across the atolls, with the S’ly energy due to hold tomorrow thanks to a reinforcing pulse arriving overnight.

Building levels of small to moderate sized S/SE trade-swell are then due into later Thursday but more so Friday, persisting through the weekend and into next week.

The size looks to mature to 4-5ft from Sunday, holding early next week before possibly easing later but we’ll review this Thursday.

There also should be a pulse of moderate sized S’ly groundswell in the mix for Monday afternoon and Tuesday, generated by a strong low firing up south of South Africa over the coming days.

Following this an active storm track to the south-east of South Africa should continue to provide plenty of S’ly swell for the region, but check back Thursday.

Eastern Indonesia:

Small surf tomorrow morning.

Small, inconsistent mid-period SW swell for later tomorrow and Thursday to 4ft across exposed breaks, easing Friday and Saturday. 

Moderate sized, inconsistent S/SW groundswell building Sunday afternoon, peaking Monday morning to 4-5ft+ across exposed locations, easing.

Smaller reinforcing swells for later week.

Weak S/SE-S/SW trades over the coming week, variable offshore each morning. Weak E/SE-SE trades kicking back in from mid-late next week.

Uluwatu 16-day Forecast Graph/WAMs

Western Indonesia/Mentawais/South Sumatra:

Small to moderate sized mid-period SW swell building tomorrow afternoon to 3-5ft, holding a similar size Thursday, easing Friday.

Small, inconsistent S’ly groundswell for later Sunday but more so Monday to 3ft across exposed breaks.

Fresh to strong S/SE winds across southern locations today, easing slowly through the coming days, tending W/SW-SW to the north.

Lighter S/SE-SE winds Saturday, variable from Sunday. Possibly freshening again across southern locations from early-mid next week. 

Mentawai 16-day Forecast Graph/WAMs

Maldives:

Small SE trade-swell with some reinforcing S’ly swell to 3-4ft across the southern atolls tomorrow, smaller Thursday.

Slow increase in S/SE trade-swell from Thursday but more so Friday, reaching 4-5ft (smaller Male) across exposed breaks Sunday, holding Monday/Tuesday, easing slowly from Wednesday.

Moderate sized S’ly groundswell for later Monday, peaking Tuesday to 3-5ft across the southern atolls.

Freshening W/NW winds across northern and central locations tomorrow, variable to the south, winds easing and tending more W-W/SW later week, S to the south.

W/SW-W winds across northern and central locations on the weekend, tending W/NW-W next week. S winds to the south on the weekend, variable next week.