Bali and Mentawais forecast​​​​​​ by Craig Brokensha (issued Tuesday 27th June)

Best Days: Swell magnets each morning over the coming days, better surf from Monday

This week and next (Jun 28 – Jul 7)

Bali: Small to moderate amounts of S/SW swell have been seen at magnets the last few days, but to no major size.

We'll see our run of small swell continue through most of this week ahead of some new SW groundswell late week.

This run of average surf is due to two large highs setting up a blocking pattern across the Indian Ocean, deflecting any major swell producing fronts away from Indonesia.

With this we have to rely on very inconsistent long-range groundswell energy which doesn't look to top the 4ft range across magnets over the coming couple of days.

Into the end of the week a slightly stronger but very inconsistent long-range SW groundswell is due, generated late last week by a strong storm directly under South Africa.

This swell should build slowly through Friday and peak Saturday to 4-6ft at swell magnets, but the waits between sets will be in the order of 10 minutes or more.

Of greater importance is a larger and more consistent S/SW groundswell due early next week.

This swell is forecast to be generated by a strong polar frontal system projecting north-east towards Western Australia from the Heard Island region tomorrow evening.

A fetch of gale to severe-gale SW tending S/SW winds will be projected nicely through our southern swell window, producing a large long-period S/SW groundswell for Monday afternoon/evening and Tuesday morning.

Exposed magnets to the south swell are expected to see sets reaching 6-8ft by dark, holding into Tuesday morning around 6-8ft+ before easing through the afternoon, further the rest of the week.

With the southerly swell direction, the Bukit reefs further tucked in along the peninsula will see less size.

Winds over the coming period look favourable with moderate to fresh E/SE trades (light and variable early each morning), becoming lighter into the middle of next week.

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

Ments: We're currently seeing small amounts of background SW groundswell energy, ebbing and pulsing between 3-5ft at magnets. This should continue through tomorrow and Thursday ahead of the new SW groundswell Friday, generated south of South Africa.

Better 5-6ft sets are due across swell magnets and variable breezes are due to take a slight SE bias as the swell peaks.

A drop in size is due Saturday, further into Sunday, while the S/SW swell expected across Bali will be generated very late in our swell window. With this we're only due to see smaller S'ly swell spreading radially up into us, building later Monday and peaking Tuesday in the 6ft range.

A slow drop is then due into Wednesday, with some new inconsistent S/SW groundswell late week from a strong but unfavourably tracking low south-east of South Africa.

Variable winds are due to kick back in from early next week, favouring most locations across the region.

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