Java, Bali, Lombok, Sumbawa forecast by Craig Brokensha (issued Thursday 25th June)

Best Days: Saturday onwards (experienced surfers only for the larger days)

This week and next week (Jun 17 – Jul 3)

Some inconsistent S/SW groundswell should be filling in across exposed breaks today and this will ease back into tomorrow from 3-5ft under strong E/SE trades (lighter and more variable at dawn).

Of much grater importance is the very large and strong pulse of SW groundswell due into the weekend and then follow up S/SW swells early next week.

Over the weekend and earlier this week a vigorous polar low generated a fetch of storm-force (50-60kt) W'ly winds through our far swell window west of Heard Island. This set in motion a large active sea state for an additional broad and expansive fetch of severe-gale W/SW winds to move over, almost as large as Australia.

This has resulted in a large long-period SW groundswell to be generated, with the 25s fore-runners (with no real size) due to arrive later Friday ahead of the groundswell proper filling in strongly Saturday.

This swell has already hit Margaret River with peak periods of 22s and a jump in size to 8-10ft. We'll see the swell building rapidly and strongly Saturday, reaching 10-12ft at exposed breaks by dark.

A peak is due Sunday to 10-12ft with 15ft bombs at swell magnets. What should also be kept in mind is that the long-period nature of the swell will likely see it focussing into some spots and missing others, so if your favourite reef isn't performing, a scout around would be recommended.

A secondary slightly more southerly S/SW groundswell pulse is due Sunday afternoon, generated by a secondary intensification of the large expansive fetch of W/SW gales between Heard Island and WA yesterday and today. This should keep the swell up all day, before easing back slowly through Monday from 10-12ft+ and then down from the 10ft range across exposed breaks Tuesday.

This slow easing trend will also be due to another reinforcing S/SW groundswell from a final vigorous polar front firing up in our swell window today. A fetch of severe-gale W/NW winds followed by a short-lived burst of storm-force winds, should produce a final large S/SW groundswell pulse for Tuesday.

A more noticeable drop in size is then due from Wednesday, with no significant swells at all showing on the charts until the following week. More on this Tuesday.

Strong E/SE trades are due to continue through the weekend and peak of the swell before easing off a touch into next week. In saying this early each morning winds should be lighter and more variable.

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