Bali and Mentawais forecast​​​​​​ by Craig Brokensha (issued Tuesday 18th October)

Best Days: Every day over the coming period besides Tuesday

This week and next (Oct 19 – 28)

Bali: Today a very inconsistent S/SW groundswell should be breaking across exposed south facing breaks, with sets up to 5-6ft, with the rare bigger one, easing into this afternoon and down further from 4-5ft tomorrow morning.

Our long-period S/SW groundswell due into Thursday and Friday has been upgraded a little, with the polar low generating this swell being a touch stronger than forecast last week.

A fetch of severe-gale to storm-force W/SW winds were generated in our southern swell window along the polar shelf, with the swell impacting South Western Australia today.

Large 10-12ft waves are being seen, with the swell due to fill in Thursday, building to a large but inconsistent 5-6ft at exposed south facing breaks later in the day, with a couple of 8ft sets more than likely.

A peak is due overnight, with easing surf from a similar size Friday morning, further into the weekend.

Some small to moderate sized reinforcing S/SW swell is on the cards for the weekend with inconsistent 4-5ft+ waves at magnets, easing into early next week and bottoming out Tuesday evening.

Longer term there's nothing too major on the cards, with an inconsistent SW groundswell for Wednesday to 3-4ft+ or so, followed by a possible larger S/SW groundswell on the weekend. We'll look at this in more detail Thursday.

Weak E/SE trades are due over the coming period, strongest Saturday and Sunday, and variable each morning with local land breezes.

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

Ments: Our current period of fresh NW winds have finally eased off into today, with some fun but less than ideal mid-period S'ly energy breaking across exposed breaks.

A drop in size is due through tomorrow from 4-5ft at south facing breaks, while the inconsistent S/SW groundswell for Bali on Thursday/Friday will come in at a smaller and even less consistent 3-5ft across our region.

From Friday afternoon the swell will ease away with small surf due into the weekend and early next week.

The SW groundswell mentioned above for Bali, will be better for the Ments, with it being generated closer to us, by a mid-latitude low that's developed south-east of Madagascar.
The swell will fill in Tuesday and peak around 3-5ft, easing off into Wednesday. Longer term some bigger S/SW groundswell is on the cards for later in the week and weekend, more on this Thursday.

Winds will remain variable over the coming days, increasing a little from the W/NW Sunday, persisting until Tuesday before weakening and tending variable again.

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