UPDATE: Wednesday July 14 8am: The swell is hitting Indonesia as we speak and it's looking considerably sizey.
This sytem can be traced back to a disturbance that formed on the periphery of a low in the far south of the Indian Ocean near the Kerguelen Islands, around the end of last week. This quickly developed and moved northeast, becoming a powerful system west of Australia by Sunday.
With high pressure pushing up against the western flank of this system, an area of storm-force southwest winds developed, which sent a large, long-period swell towards Indonesia. Wave heights at, say, Uluwatu are currently around ten feet with periods of around 16 secs. The swell is expected to persist into Thursday, and gradually lose size and quality during Friday and Saturday, before further pulses of long-period swell – albeit not as epic as this one – arrive late in the weekend and into next week.
Here's Nias from today! More coming, very soon.
EARLIER:Spots across everyone's favourite archipelago could be about to go into overdrive with an XL, and extra-close, swell about to rifle into Indo from mid-next week.
For as exciting as it sounds though (and we're frothing out on it right now...) the likes of Bali has just gone back into lockdown. Beaches closed until July 19 at the earliest, around five days or so after this run of swell hits. Also, what's causing slight concern, is how close this all is to Indo, the storm actually intensifies quite far east, over an already agitated sea state. But we'll keep an eye on this over the next few days.
Anyway, it's a little ways out yet – it will potentially hit this time next week. But in prep, we thought we'd break it all down. Also, a little comparison about how it stacks to July 2018, one of the largest swells to hit Indo in the past few years.
If you're looking at that chart and thinking, 'huh, what about West Oz', don't worry, we are too. At the moment, it's marred by strong onshore winds as the swell hits (of course) but the days after there might be something special. We're keeping a close eye on it and will update as and when.
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“The Indian Ocean charts are currently showing a fairly average looking low pressure system southeast of South Africa, and a band of high pressure stretching across from southern Madagascar to Western Australia,” says MSW forecaster Tony Butt.
If this happens, a large, long-period swell will be generated, heading for Indonesia
“Over the next few days, the high is expected to shrink westwards as a peripheral low centre develops and arcs around the eastern side of the high. As a result, a moving windfield of storm-force southerlies develops. The windfield persists as it moves north-northeast, still generating swell from a position much further north than usual, with the storm itself hitting Western Australia late in the weekend. If this happens, a large, long-period swell will be generated, heading for Indonesia.
“The large virtual fetch and the fact that the windfield ends up closer than usual, means that the swell hitting Indonesia will probably be large. Current long-term forecasts for Uluwatu, for example, suggest the main bulk of the swell hitting around the middle of next week, persisting till around Friday 16th, with wave heights that could exceed ten feet.
“This is expected to arrive on top of an already pumping swell from a previous system, with six-to-eight foot surf early in the week.
“This time three years ago – July 2018 – saw a run of spectacular swells hitting Indonesia, with wave heights over 15 feet several times during the month, and periods exceeding 20 secs on a regular basis.
“These swells were generated by more powerful systems than the present one, but which had dynamic fetches which helped to enhance the swell. The 2018 systems mostly deepened half way across the Indian Ocean, whereas the present one peaks in intensity quite far east.”