Bali, Indonesia Surf Forecast 8 - 20 August, 2018

7 Aug 2018 1 Share

Ben Macartney

Chief Surf Forecaster

Forecast Issued Tuesday, 7 August, 2018


Pregnant with broadscale low-pressure, the southern Indian Ocean pushed out some seriously oversized pulses SSW groundswells for Indonesia throughout late July and early August. But, as they say, what goes up must come down – and that’s exactly what’s going on across The Archipelago this week. Indonesia’s swell window is now in the midst of a well-earned rest – and hence won’t be pumping out any major swell-events in the near-term. Thankfully, there are already emerging indications this suppressed phase in wave-activity will come to an end, leading in a return to winter-scale surf across the region into the middle of the month.

A subdued phase in storm-development sees a return to modest-sized surf this week, with more on the horizon for the middle of the month. Photo: Kanduiviallas.com

A subdued phase in storm-development sees a return to modest-sized surf this week, with more on the horizon for the middle of the month. Photo: Kanduiviallas.com

Daily Summary

Wednesday 8
Mid range SSW groundswell steadily eases from 3 to 4ft exposed breaks, grading smaller elsewhere depending on exposure. WIND: Early light and variable tending ESE around 10 to 15 knots.

Thursday 9
SSW groundswell slowly eases. Initially still ranging from a slow 1 to 3ft exposed breaks, grading smaller elsewhere and fading into the afternoon. WIND: Early light and variable tending SE 10 to 15 knots.

Friday 10
Residual SSW swell up to an inconsistent 1 to 2ft exposed breaks, grading to tiny or near flat elsewhere depending on exposure. WIND: Early light and variable tending ESE 5 to 15 knots.

Saturday 11
Modest SSW groundswell arrives from 215 degrees, rising from 2 to 3ft+ early to 3 to 4ft across exposed breaks during the day. Grading smaller elsewhere with size depending on exposure. WIND: Light and variable tending SE around 10 knots.

Sunday 12
SSW groundswell holds around 3 to 4ft on the sets across exposed breaks. Grading smaller elsewhere depending on exposure. WIND: Early light and variable tending SE 10 to 15 knots.

Monday 13
Faded SSW swell around 2 to 3ft+ exposed breaks, grading smaller elsewhere with size depending on exposure. WIND: Early light and variable tending ESE 10 to 15 knots.

Tuesday 14
Residual SSW swell around 2ft exposed breaks and further easing throughout the afternoon. Grading smaller elsewhere with size depending on exposure. WIND: Early light and variable tending SE around 5 to 15 knots.

Wednesday 15
Scope for a modest building trend in SW groundswell from slight 1 to 2ft levels towards 2 to 3ft across exposed breaks during the afternoon. Grading smaller elsewhere with size depending on exposure. WIND: Early light and variable tending SE about 10 knots.

Overview
And just like that, conditions have reverted to relatively subdued levels this week – and going in latest model runs it looks like they’ll stay that way for some time to come. In the wake of July’s sustained run of oversized surf we’re now looking at a return to small to occasional mid-sized SSW groundswells enduring right trough to the middle of August. Having said that, there’s still enough storm activity to ensure the waves keep rolling in over this period.

In the short term we have an easing SSW groundswell set to scale down over the next 48 hours; initially leaving us with fun-sized leftovers in the 2 to 3ft plus range early on Wednesday morning. However, this energy will continue to wane into the end of the week; probably fading to a slower 2ft across exposed coasts on Thursday before bottoming out at a very meagre 1 to 2ft or less on Friday morning.

It won’t be until Saturday that we’ll see a new, albeit still very modest round of SSW groundswell arriving from 215 degrees restoring wave-heights to a meaningful size across the region. For now this looks like kicking off with a gradual building trend into the 3 to 4ft range across the most exposed reefs during the day, with scope for another full day of waves around this size on Sunday. The origin of this pulse is a moderate-strength mid-latitude low now tracking eastward across the southern Indian Ocean, directly below the Archipelago. Over the next 24 hours the storm sets up a well aligned 30kt SSW fetch with Indonesia; in turn sending up a respectable pulse of mid-period energy arriving just in time for the weekend.


A short-term decline in SSW swell precedes the arrival of a new, mid-sized SSW pulse across Indonesia this weekend. Source: Wave Tracker.

A short-term decline in SSW swell precedes the arrival of a new, mid-sized SSW pulse across Indonesia this weekend. Source: Wave Tracker.

Long Range
However, an absence of notable new swell-sources following this storm means we’ll see a renewed easing trend in energy following this weekend’s pulse; initially hanging in around the 3ft mark early on Monday before dropping out to increasingly small to tiny levels on Tuesday 14th and culminating in virtually flat conditions early on Wednesday 15th August. From there, the outlook begins to shift back in our favour with a renewed building trend loosely projected to set in late Wednesday, leading in a few days of solid surf throughout Thursday 16, Friday 17th and Saturday 18th August.

This hinges on the evolution of a very large, complex area of low pressure forecast to migrate slowly eastward across the south-western Indian Ocean over the coming days. Regardless of its impressive scale, the absence of an substantial high pressure adjacent to the storm looks like inhibiting potential for any major, long-period swell-event. Never the less, the development of a broad, low-strength WSW fetch spanning latitudes bounded by 30S and 60S presents good potential for a sustained run of mid-period SW groundswell; the leading edge building in late Wednesday 16th ahead of the bulk of swell arriving in the 4 to 8ft range from Thursday 16th to Saturday 18th out of the 215 to 220 degree band.

From there, we’re just starting to see some emerging consensus among the key models surrounding the development of an intense polar low over the far south-eastern Indian Ocean early next week. Latest GFS runs are looking bullish on this system; picking up a 40ft sea-state resulting from it’s rapid development on Monday and Tuesday 14th; setting up a refracted pulse of large, long-period SSW groundswell from 190 to 200 degrees; speculatively arriving during the period of Saturday 18th through Monday 20th. Beyond that we start to see telescoping model divergence lending increasing uncertainty to the outlook for late August, so check back next Tuesday for clearer guidance.


The prospective development of another deep polar low early next week presents a good case for a new, powerful SSW groundswell arriving around the 18th to 20th August. Source: Wave Tracker.

The prospective development of another deep polar low early next week presents a good case for a new, powerful SSW groundswell arriving around the 18th to 20th August. Source: Wave Tracker.


Tags: Indo Surf Forecast , Ben Macartney (create Alert from these tags)

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