The Bolivian, Botswana, and Bilybara Highs and Southern Hemisphere drought/floods

Abstract Semipermanent anticyclones in the midlevel troposphere over the subtropical landmasses are a prominent component of Southern Hemisphere climate. Typically, they occur over Bolivia, Botswana/Namibia, and northwestern Australia from austral spring to about April and are strongest in late summer. Here a mode of variability is studied that modulates the strength of these midlevel anticyclones and which is not strongly tied to El Niño–Southern Oscillation. This mode leads to variations in January–March rainfall over large parts of South America, southern Africa, and Australia on both interannual and near‐decadal scales.