Nias, Mentawai, South Sumatra forecast by Craig Brokensha (issued Tuesday 18th February)
Best Days: Sunday onwards
This week and weekend (Feb 18 - 23)
There hasn't been too much action in the Indian Ocean the last few days and this will result in only small and very inconsistent levels of background swell energy across most of the Indonesian archipelago over the coming week.
Light variable winds should create generally clean conditions in between localised thundersqualls and storms.
Next week onwards (Feb 24 onwards)
Some better but very inconsistent SW groundswell pulses are due to arrive through Sunday and early next week across the region as a flurry of polar fronts fire up in and around the Heard Island region over the coming days.
Unfortunately the storm activity will be quite some distance away from the Sumatran region (6,000km) and there'll be no significant frontal system aiming a consolidated fetch towards us. More so bursts of 30-35kt winds over active seas, setting in motion a couple of pulses of medium sized and very inconsistent SW groundswell.
The first pulse should fill in Sunday and peak during the afternoon, but a better pulse is due later Monday ahead of a peak Tuesday to around 3-5ft at exposed spots to the SW swell (with larger sets likely across Southern Sumatra).
Winds should remain light and variable through this period creating clean glassy conditions in between localised thunderstorms.
Longer term there's nothing major on the cards, with a blocking high setting up west of Western Australia leaving us to rely on similar long-range and inconsistent swell energy expected at the start of next week.
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