Bali and Mentawais forecast​​​​​​ by Craig Brokensha (issued Tuesday 2nd May)

Best Days: Every day over the coming period for both regions

This week and next (May 3 - 12)

Bali: We've got some good SW groundswell breaking across the islands today, peaking through yesterday and easing off slightly into this morning. With the SW direction the Bukit reefs are seeing a more uniformed spread in size.

Into tomorrow we'll see the swell bottom out temporarily early ahead of the secondary pulse of inconsistent SW groundswell building through the day.
The morning should still be an inconsistent 4-5ft across exposed breaks, building further to 5-6ft through the afternoon. From Thursday the swell will slowly ease with 5-6ft sets early, smaller from 3-5ft Friday morning.

Now, looking ahead to our larger S/SW groundswell event due over the weekend, and the size has been pulled back a bit from last Thursday.

The vigorous and slow moving polar frontal progression generating this swell is forecast to be a touch weaker, with it forming in the Heard Island region yesterday. A slow moving fetch of gale to severe-gale W/SW winds projecting north-east through our swell window will generate a large long-period S/SW groundswell for Sunday and Monday.

The groundswell should build through Sunday, reaching 6-8ft across exposed breaks, more consistently near that 8ft range Monday morning. A drop in size is expected Monday afternoon, further down through Tuesday and Wednesday.

Fresh E/SE trades are expected to kick in from Thursday afternoon, persisting all weekend and further through next week.

Later in the day Wednesday an inconsistent new SW groundswell is due, produced by a strong but a little off axis fetch of severe-gale S/SW winds projecting from the south-west Indian Ocean up through the central Indian Ocean over the coming few days.

This swell should build to 4-5ft by dark Wednesday, peaking Thursday, but over-ridden by a larger S/SW groundswell.

This larger groundswell is due to be bigger than Sunday/Monday's, generated by a much more significant polar front firing up west of Heard Island, directing a fetch of severe-gale to storm-force W/SW tending SW winds up into the Indian Ocean.

Hopefully the models don't change to much with this system, but at this stage we're looking at large surf in the 10ft+ range, but lets have another look at this Thursday.

16 day Bali Forecast Graph
16 day East Java Forecast Graph
16 day Sumbawa Forecast Graph

Ments: Some great waves the last few days with a new SW groundswell, but the surf is easing back through today.

Tomorrow the slightly better SW groundswell should build to a solid 5-6ft+ through the day across exposed breaks with variable breezes, easing back slowly Thursday and Friday.

The downgraded swell for the weekend should still provide solid surf across the Mentawais, with a pre-cursor swell Saturday kicking to 4-6ft ahead of the groundswell proper Sunday, upwards of 6ft, with a reinforcing pulse Monday to 5-6ft+.

Winds should remain favourable and variable through the whole period keeping conditions nice and clean.

The larger S/SW groundswell for late week looks to come in at 8-10ft+ across the Mentawais Thursday, but again we'll look at this closer on Tuesday.

16 day Mentawai forecast graph
16 day Nias forecast graph
16 day South Sumatra forecast graph