Indian Ocean Basin analysis by Craig Brokensha (issued Thursday 26th December)

This week through next (Dec 27 - Jan 3)

Later today we should start seeing our new, long-range SW groundswell building, with some reinforcing energy in the mix for tomorrow.

Across Western Australia this swell performed in a fairly hit and miss nature. The Margaret River region didn’t quite get to the expected size while locations further north did.

With this in mind, expect surf mostly in the 6ft range across exposed breaks but don’t rule out the odd bomb sneaking through.

We should see the swell easing into the weekend, bottoming out later Monday.

At the same time, strengthening monsoonal winds are due over the coming days before starting to abate from Tuesday onwards, more variable late week.

As touched on in Tuesday’s update, the next noticeable increase in swell energy is due through Thursday next week, with some new mid-period S/SW swell energy due to be followed by some larger S/SW groundswell next Saturday.

The source will be back to back healthy lows projecting towards Western Australia over the coming days, the first generating a fetch of sub-gale-force W/SW winds and moderate sized mid-period S/SW swell for Thursday, peaking into the afternoon.

A secondary slightly stronger but less favourably aligned system firing up on the tail of the first should produce a slightly stronger but less consistent S/SW groundswell for the following Saturday, peaking into the afternoon.

Following this the Southern Ocean goes a little quiet so make the most of the coming swells.

Over in the Mentawais we should be seeing the new SW groundswell in the water and strong W/NW-NW winds are due to abate tomorrow before freshening a little across southern locations through the weekend.

Winds should then slowly back off through next week but so will the swell sources with the systems to the south-west of WA not expected to produce much size.

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Maldives: As the S’ly swell energy eases in size, SE trade-swell is becoming the more dominant energy across the Maldives though to a slow 3ft or so.

Over the past few days we’ve seen the trade-winds to the south of Indonesia really strengthen nicely and this now looks to generate moderate levels of swell that should start building through the weekend but peak next Monday/Tuesday.

Now the models diverge regarding the possibility of a tropical low deepening into a cyclone south of Sumatra. This would generate more size into next week but we’ll review this on Tuesday.

Some small-moderate sized mid-period S’ly swell is then due next Wednesday but to no major size.

Weak NW winds are due to shift N/NW through tomorrow but only remain light with N’ly winds Saturday, possibly shifting NE on Sunday. The rest of next week is a little unsure but we could see variable winds tending E’ly across northern locations, W’ly to the south.

Eastern Indonesia:

Mod-large mix of SW and S/SW swells to 6ft across exposed breaks tomorrow, easing into the weekend. 

Moderate sized mid-period S/SW swell for Thu, peaking into the afternoon to 4-5ft+.

Stronger S/SW groundswell Saturday kicking to 6ft+ across exposed breaks.

Mod-fresh W/NW-W/SW winds, easing from Tuesday next week and variable thereafter.

Uluwatu 16-day Forecast Graph/WAMs

Western Indonesia/Mentawais/South Sumatra:

Mod-large SW groundswell for today to 6ft+, easing tomorrow.

Small, inconsistent SW groundswell building Monday, peaking Tuesday to 4ft. 

Small-mod sized S/SW swell Thursday to 4ft across exposed breaks.

Secondary inconsistent S’ly groundswell next Saturday/Sunday to 4ft across exposed breaks. 

Strong W/NW-NW winds, easing tomorrow but freshening again on the weekend across southern locations. More variable winds developing next week.

Mentawai 16-day Forecast Graph/WAMs

Maldives:

Background SE trade-swell to 3ft building into the weekend and peaking Monday/Tuesday to 4ft+ or so. Swell trend unclear for the rest of the week.

Small-mod sized S’ly swell next Wednesday to 3ft across the southern atolls.

Light N/NW winds tomorrow with N’ly winds Saturday, possibly shifting NE on Sunday. 

Next week is a little unsure but we could see variable winds tending E’ly across northern locations, W’ly to the south.