Nias, Mentawai, South Sumatra forecast by Craig Brokensha (issued Tue 21st Oct)

Best Days: Every day at exposed breaks in the Ments (South Sumatra from Friday)

This week and weekend (Oct 21 - 26)

A new S/SW groundswell seen across the region later yesterday and this morning should be providing OK waves across exposed breaks with light morning SE winds favouring slightly protected south-west facing breaks.

A drop in size is due through this afternoon and further tomorrow across the islands, bottoming out Thursday to the inconsistent 2ft to occasionally 3ft range at exposed breaks around the Ments (a touch bigger around South Sumatra).

Friday should see a fun but acute S'ly groundswell arriving across the region, generated by a strong polar low that developed around the Heard Island region over the weekend. A fetch of severe-gale S/SW winds were projected towards Eastern Indonesia, producing the larger period swell with exposed spots in the Ments expected to offer 4-5ft+ waves Friday with larger 6ft sets in South Sumatra.

This swell will then ease through Saturday and further Sunday, bottoming out through the middle of the day.

Winds should really ease back over the coming days and tend variable from Thursday and remain so through most of next week, favouring exposed breaks.

Next week onwards (Oct 27 onwards)

Another pulse of S/SW groundswell is due on Monday, similar to Friday's pulse but likely just coming a touch under in size and power.

This will be generated by a weaker polar frontal system pushing through the Heard Island region towards WA today and tomorrow, with moderate amounts of S/SW swell spreading up radially towards us.

The Ments are only expected to see inconsistent 4-5ft waves at exposed breaks with the odd 6ft bomb around South Sumatra before tailing off into Tuesday and Wednesday.

Longer term we look to continue to see moderate sized pulse of S/SW swell across the region but there's nothing too significant brewing for our region unfortunately. Check back Thursday for any change to this.

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