AAO Takes A Dive

The long predicted dive in the Antarctic Oscillation (also known as the Southern Annular Mode) looks like it will kick in over the next week or so….and that could mean some interesting weather for us over the next couple of months. The latest forecast is below:

For the nerds amongst us I’ve also thrown together a quick animation that shows the AAO over the last 10 days. The top is up high in the atmosphere, while down the bottom is ground level. You can see the strongly negative values up high, which are now starting to move towards the surface:

In a nutshell, the more negative the AAO turns the further north the westerly winds will move – and that can be important for us. As a quick guide to the potential impacts you’d do well to check out this excellent video from the BoM:

The takeout from all this? That we’re likely to see some interesting weather over the next c0uple of months. There is an increased risk of hot, dry and windy weather – but also a chance that an upper cold pool will come wandering further north than normal and give us a big downpour. I’ll keep you posted with what looks likely to happen!

This Post Has 3 Comments

  1. Sandra Finn

    hi Kev thank you not sure of all I look at but really appreciate your interpretations in words ,
    the graphs are a bit beyond me but great to try to understand ,
    a learning cure so to speak 🙂

  2. It will be very interesting to see what actually happens – hopefully the cold pool will move north and increase the instability in the atmosphere over us….but previous negative SAM events this year have lead to very dry

  3. Paul Netterfield

    As usual, a learning experience. Thank you for the explanations and post. I’m looking forward to the possibility of rain events but not the dry westerlies.

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