Java, Bali, Lombok, Sumbawa forecast by Craig Brokensha (issued Tuesday 10th May)

Best Days: Swell magnets tomorrow, Friday and Saturday, experienced surfers on the reefs from later Sunday

This week and next (May 11 – 20)

Great waves to end last week, easing through the weekend. Some new S'ly swell is due across the coast today and tomorrow, with swell magnets expected to see sets to 3-5ft, becoming small Thursday.

Through Friday and Saturday only small background SW groundswell energy is due, with inconsistent sets to 3-5ft across exposed breaks.

Moderate to fresh E/SE trades are due to kick in from this afternoon, persisting into the weekend and next week, but each morning more variable and local offshore winds are due.

Of much greater significance is a series of vigorous polar fronts firing up through the southern Indian Ocean from today through the following two weeks.

Currently the strongest of all the frontal systems is developing west of Heard Island, with a smaller mid-latitude front just at its head.

We'll see a fetch of gale to severe-gale SW winds projected slowly north-east and then east through our swell window, generating a large long-period SW groundswell for Monday.

Through Sunday though a good moderate sized SW swell is due from the mid-latitude front, building to 5-6ft+ by dark, with the larger groundswell Monday peaking around 10ft+ across exposed breaks.

A drop in size is due through Tuesday from 8-10ft, and further through Wednesday before bottoming out during the day Thursday.

Another slightly stronger but smaller polar front will move through our southern swell window from Friday evening through the weekend, generating a less consistent but large long-period S/SW groundswell later in the week. A peak is likely Friday in the 8ft range, but more on this Thursday.

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