An ominous long-range forecast with predictions of an El Niño forming in spring that would bring hot and dry conditions for the second half of the year kicked off 2023. Thankfully the lingering La Niña in 2022 resulted in great stored soil moisture levels and some timely rain events at the start (March) and end of sowing (June) helped get crops up and away. The climate drivers in the Pacific and Indian Oceans had a brief reset during autumn/early winter but a predominantly -ve Southern Annular Mode (SAM) in June and July brought much needed rain. This had us questioning whether the increased chance of a hot and dry spring would come to fruition. During winter sea surface temperatures, trade winds and the pressure patterns began to link up for an active El Niño and a +ve IOD to be declared by the Bureau of Meteorology (BoM) in September. This contributed to the dry conditions experienced in early and mid-spring but above average rainfall was recorded in October at some locations. This rainfall roller coaster resulted in many places receiving average GSR (decile 5) despite the ‘drying’ climate drivers at play (Table 1). This was not completely unexpected as Figure 1 demonstrates. Historical rainfall records show an El Niño has only delivered dry conditions in five to eight years out of the 15 declared El Niños since 1960 at the four locations shown. This highlights just how complex our climate is and that there are many factors at play which can also help explain why the models didn’t always get it right in 2023.
Table 1. Growing Season Rainfall (mm) across the Wimmera, Mallee and North Central regions, number in brackets denotes decile for the period (April to October).
Figure 1. Growing season (Apr-Oct) rainfall totals across 15 El Niño years since 1960 and four different locations. Source: Local Climate Tool.
