BAMOS November 2025
8 Article
Regarding SAM, it was already negative before the SSW event( Figure 3), and the apparent downward propagation of the stratospheric signal might be a coincidence or our eyes trying to make connections where none exist. That, of course, is the excitement of research— finding out what ' s been going on in the Southern Hemisphere in spring 2025 is going to produce quite a few papers in the coming years.
Figure 2: Chance of exceeding median rainfall from the Bureau of Meteorology’ s seasonal forecast bulletins. The bulletin dates are given for each panel, along with a rainfall prediction summary. The first five panels show forecasts for October – December, the last three for November – January. The last panel shows observed rainfall anomalies for 1 – 20 October. Credit: Bureau of Meteorology( https:// www. bom. gov. au / climate / ahead / outlooks / archive. shtml and https:// www. bom. gov. au / climate / maps / rainfall /)
Figure 3: top: Normalised polar cap geopotential height anomaly( SAM proxy: red ~ negative SAM). Bottom: Antarctic Oscillation index( negative index ~ negative SAM). Credit: Climate Prediction Center