Indian Ocean Basin analysis by Craig Brokensha (issued Thursday 15th August)

This week through next (Aug 16 - 23)

Following the swell earlier in the week, a reinforcing pulse of slightly lower period and more south swell is due into this afternoon and tomorrow morning, adding a little boost in size on top of the current easing trend.

This swell will ease into the weekend, with our new SW groundswell due into later Sunday ahead of a peak on Monday.

The source is a strong, small, tight low moving in across the southern Indian Ocean with a fetch of gale to severe-gale W/SW winds.

On the backside of the low today, a more southerly positioned fetch of severe-gale S/SW winds are adding an additional S/SW component to the swell. This will project slowly north towards us while weakening tomorrow and Friday, generating some further, consistent but weaker mid-period energy to the mix.

Timing wise, an increase in inconsistent SW groundswell is due late Sunday (earlier Ments) but the bulk of the energy is due on Monday. 

The swell should then slowly ease Tuesday, further Wednesday ahead of our inconsistent, long-range SW groundswell for Thursday.

The storm linked to this swell is currently producing large, pumping waves in South Africa with a fetch of distant severe-gale to storm-force W/SW-SW winds due to generate a good pulse of SW groundswell for Thursday afternoon, easing slowly Friday and further next weekend.

Longer term the outlook still remains very active with a possible significant Southern Ocean frontal progression due to project up and towards us later next week, generating a larger SW groundswell for early the week starting the 26th. More on this in next week’s updates.

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Across to the Maldives moderate + levels of SE trade-swell are due to replace S/SE energy into the weekend, generated by a great fetch of SE trades setup south-east of the region.

The low spawning off Madagascar will also generate some S’ly groundswell for the weekend, though only moderate in size with the storm off South Africa generating a larger groundswell for Tuesday afternoon and Wednesday morning.

Strong winds from the north-western quadrant will make for tricky conditions across selected spots over the coming days, easing from about Tuesday but more so Wednesday.

At the same time the SE energy is due to ease through next week, with the next pulse of energy due to arrive from the S/SE later week thanks to a new fetch of strong E/SE trades forming south of us during the week.

Eastern Indonesia:

Reinforcing S/SW groundswell this afternoon/tomorrow morning to 6ft to occasionally 8ft, easing through the weekend.

Large, inconsistent SW groundswell building later Sunday, peaking Monday with a large S/SW swell also in the mix to 8-10ft across exposed breaks.

Large, less consistent SW groundswell for Thursday afternoon/Friday morning to 8ft across exposed breaks.

Possible larger swell for early the following week.

Moderate to fresh E/SE-SE trades tomorrow, weaker on the weekend and more E/SE-SE. Slightly fresher winds early to mid-next week. Light, variable, local offshore winds each morning.

Uluwatu 16-day Forecast Graph/WAMs

Western Indonesia/Mentawais/South Sumatra:

Reinforcing S/SW groundswell later today and tomorrow morning to 6ft.

Large SW groundswell building Sunday, reaching 6-8ft into the evening, with a reinforcing S/SW groundswell Monday to a similar size, easing Tuesday.

Large, less consistent SW groundswell building Wednesday, peaking Thursday morning to 8ft across exposed breaks.

Possible larger swell for early the following week.

Strong S/SE-SE trades across southern locations this week and over the weekend, little weaker early next week, strengthening again from Wednesday. Lighter winds to the north.

Mentawai 16-day Forecast Graph/WAMs

Maldives:

Moderate + sized S/SE trade-swell easing a little into tomorrow from 4-5ft across exposed breaks.

Moderate + sized SE trade-swell building Saturday afternoon to 4-5ft+ across exposed breaks, easing slowly Sunday from a similar size and smaller next week.

Small-moderate sized S’ly groundswell for Sunday/Monday to 3ft across south magnets.

Larger S’ly groundswell building Tuesday to 4-6ft on the southern atolls into the afternoon, easing Wednesday.

Moderate sized S/SE trade-swell building later next week and persisting the following weekend.

Strong W/NW-W winds across all locations tomorrow, tending W/NW-NW through the weekend and remaining strong.

Winds slowly easing from Tuesday but more so Wednesday.