South Pacific Convergence Zone Weather

The Austral islands are notorious for unstable, bad weather and during a La Niña phase (as we have this year) it’s supposed to be even cooler and rainier than usually. We therefore had rather low expectations weatherwise when we sailed to Raivavae at the beginning of December. We mainly wanted to keep our elderly cat ‘cool’ (she suffers in hot temperatures) and quietly work most of the time anyway.

We were extremely surprised by the stable, sunny summer weather we got for most of December and all of January. Of course we enjoyed this brilliant summer, but it turned out it was too hot for the sea: due to water temperatures around 30 degrees we noticed some severe bleaching in the few live coral bommies here in the lagoon. Staghorn and elkhorn coral lost their symbiotic algae and turned from a healthy light brown/beige to white and light pastel colours. Marine biologists told us that coral can survive just on what its polyps catch for about 3 weeks, if the symbiotic algae (that produces sugar for the coral) hasn’t come back by then the coral dies…

The weather’s changed now: the SPCZ is hanging across the Pacific and pointing straight towards us, there’s a low moving by right now and another 3 are scheduled according to the weather forecast. If you open e.g. ‘windy.com’ and look at the South Pacific you see a line from Samoa down to the Austral islands without wind – that’s the SPCZ. Whirly lows build up along that instable area and head along it southeastwards. If there’s enough energy in the atmosphere or if a few of them coincide they have potential to form cyclones. That’s the super-simplified explanation–if you’re interested in more info check out Christian’s article about South Pacific weather patterns. There’s a link to the article at https://www.pitufa.at/weather-fp/

We’re in a nice, protected anchorage and prepared for heavy gusts. The dinghy’s in the water (usually we store it hanging alongside the hull overnight, but it could slam against Pitufa during gusts), the outboard engine up on the railing and tied down, just like oars and all other possibly volatile objects. Ideal weather to work on our laptops.

Hopefully the cooler temperatures aren’t coming too late for the coral though. We’ll check when the weather’s settled down again.

PS: Our blog automatically picks a random photo for each entry and for the fb page–don’t assume we’re crazy if it happens to be a sunny one ;-)

1 comment

  1. Tetuamanuhiri Alexandre says:

    Aronga pitufa (Christian & Birgit )
    je suis actuellement sur TAHITI pour visite médical
    on a plus eu de nouvel de votre par, condoléance birgit pour ta maman
    sinon vous on va tres bien
    salutation Alexandre

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