5.4 Update on El Niño

Neutral El Nino condition prevailed across the Pacific Ocean. Figure 5.8 illustrates the behavior of the standard Southern Oscillation Index (SOI) published by the Australian Bureau of Meteorology (BOM) for the period from July 2019 to July 2020. Sustained positive values of the SOI above +7 typically indicate La Niña while sustained negative values below -7 typically indicate El Niño. Values between about +7 and -7 generally indicate neutral conditions. During this monitoring period, SOI increased from -0.5 in April to 2.8 in May, then decreased to -9.6 in June, then increase to 4.2 in July, indicating a neutral El Niño situation.

The sea surface temperature anomalies in July 2020 for NINO3, NINO3.4, and NINO4 regions were -0.3°C, +0°C, and +0.2°C, respectively, somewhat warmer than the 1961-1990 average according to BOM (see Figure 5.8 and Figure 5.9). Both BOM and NOAA conclude that the currently warmer conditions indicate a neutral El Niño (www.climate.gov/enso). CropWatch will keep monitoring the situation (Figure 5.10).

Figure 5.8 Monthly SOI-BOM time series from July 2019 to July 2020 (Source: http://www.bom.gov.au/climate/current/soi2.shtml)

Figure 5.09 Map of NINO Region (Source: https://www.climate.gov/sites/default/files/Fig3_ENSOindices_SST_large.png)

Figure 5.10 July 2020 sea surface temperature departure from the 1961-1990 average (Source:http://www.bom.gov.au/climate/enso/wrap-up/#tabs=Sea-surface)