Indian Ocean Basin analysis by Craig Brokensha (issued Thursday 11th July)

This week through next (Jul 12 - 19)

The surf is on the ease, but into tomorrow we should see our consistent pulse of large sized mid-period SW swell, easing into the weekend ahead of a less consistent but stronger S/SW groundswell late Sunday but more so Monday.

The source of both swells is effectively the same frontal progression with an initial, northward protruding frontal system generating tomorrow’s swell, while a more significant polar frontal system firing up on the backside of the storm is generating Monday’s swell.

Winds weren’t overly strong for the initial swell but it looks fun and consistent, while the polar front is producing a fetch of W/SW gales that will produce a similar sized, though less consistent, stronger S/SW groundswell for Monday.

We should see the surf starting to ease later Monday but more so Monday/Tuesday with a new inconsistent background SW groundswell arriving through Wednesday ahead of a slightly better S/SW groundswell Thursday.

The background swell has been generated by a distant storm under South Africa and only looks small to moderate in size, while the backend of the progression looks to fire up north of the Heard Island region next weekend.

Being a low isn’t ideal as the fetch length is diminished but we should see fetches of gale to severe-gale SW winds aimed through our southern swell window, producing a moderate + sized S/SW swell for Thursday afternoon and Friday morning.

Behind this low we might see a bit stronger frontal activity but at this stage the swells looks to be in the moderate to large size range compared to large, but there is potential. More on this Tuesday.

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In the Maldives, a good pulse of S/SE groundswell should be on the build today across the region, with it peaking this afternoon/tomorrow morning before easing into the weekend.

As this swell eases a renewal of SE tending S/SE trade-swell is due thanks to a great fetch of strengthening E/SE winds to the south of the region today through the weekend.

This fetch will reach maturity on Sunday before weakening and slipping a further west, away from us.

As a result moderate to large levels of swell should build on the weekend, peaking Sunday through Tuesday, easing later and further into Wednesday/Thursday.

We then look at a much more significant fetch of E/SE trades setting up through the northern Indian Ocean during next week. This looks to be the most robust fetch this season so far, generating large, strong SE swell to the Maldives from late next week. At this stage it could reach an easy 6-8ft. More on this next update.

Eastern Indonesia:

Moderate + sized mid-period SW swell for tomorrow to 6ft+ across exposed breaks.

Less consistent, stronger S/SW groundswell arriving on dark Sunday, peaking Monday morning to 6ft+, easing into the afternoon and Tuesday/Wednesday.

Small to moderate sized, inconsistent SW groundswell to 3-5ft Wednesday afternoon.

Moderate + sized S/SW groundswell Thursday afternoon and Friday morning to 4-6ft.

Moderate to fresh E/SE-SE trades (strong tomorrow and early-mid next week), variable winds each morning.

Uluwatu 16-day Forecast Graph/WAMs

Western Indonesia/Mentawais/South Sumatra:

Moderate sized + mid-period S/SW swell later today, peaking tomorrow morning to 6ft+ across exposed breaks, easing Saturday.

Less consistent, smaller, reinforcing S’ly groundswell building Monday, reaching 6ft during the day, easing Tuesday.

Moderate + sized SW groundswell for Tuesday afternoon/Wednesday to 4-5ft+.

Moderate + sized S/SW groundswell Thursday afternoon and Friday morning to 4-6ft.

Moderate sized levels of S/SE trade-swell next weekend.

Variable winds, tending S/SE-SE across southern locations into the weekend, persisting next week and becoming strong later next week/weekend while also reaching northern locations.

Mentawai 16-day Forecast Graph/WAMs

Maldives:

Moderate + sized S/SE groundswell building today, reaching 3-5ft across the southern atolls late, easing from a similar size Friday morning.

Large SE tending S/SE trade-swell building over the weekend, reaching 6ft+ on the magnets Sunday/Monday, easing slowly Tuesday.

Larger SE trade-swell for later in the week to 6-8ft across exposed breaks Friday, easing slowly next weekend.

W/SW-SW winds across the central and northern atolls, tending S across southern locations tomorrow and Saturday.

W winds Sunday, variable to the south with stronger W/SW-W winds across northern and central locations early next week with S winds to the south.