Seasonal climate summary southern hemisphere (autumn 2002): onset of El Niño conditions

Southern hemisphere circulation patterns and associated anom-alies for the austral autumn 2002 are reviewed, with emphasis given to the Pacific Basin climate indicators and Australian rain-fall and temperature patterns. Indications of the onset of a new El Nifio event became apparent by the end of autumn, although this was much more evident in the atmospheric indicators than in the oceanic ones. In the middle of the season, however, it was far from certain that an EI Nifio would develop. Autumn saw widespread below to very much below-average rainfall, accompanied by strongly elevated seasonal maximum temperatures. This below-average rainfall proved in hindsight to be the start of a particularly severe and widespread drought, whose effects were exacerbated by the persistence of the above-average temperatures seen during autumn.