El Nino conditions have been neutral across the Pacific Ocean during the first quarter of 2018. Figure 1. illustrates the behavior of the standard Southern Oscillation Index (SOI) of the Australian Bureau of Meteorology (BOM) from April 2017 to April 2018. 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 the current season, SOI increased from -1.4 in December to +8.9 in January, decreased to -6.0 in February, then jumped to +10.5 in March and decreased again to +4.5 in April. The overall fluctuation of SOI between +7.0 and -7.0 indicates that neither El Niño nor La Niña appeared in the tropical Pacific Ocean. Australian BOM reports a neutral state at current stage and from a global point of view. CropWatch will keep on monitoring its condition.

Figure 1. Monthly SOI-BOM time series from April 2017 to April 2018

Source: http://www.bom.gov.au/climate/current/soi2.shtml

The sea surface temperature anomalies in April, 2018 for NINO3, NINO3.4 and NINO4 regions are −0.2°C, −0.3°C, and +0.1°C in sequence, slightly cooler than 1961-1990 average according to BOM (see Figure 2-3.). Both of BOM and NOAA posit that the cool sea surface temperature indicates that El Nino conditions are neutral during the southern autumn, and will probably continue into the following winter (N. hemisphere summer).

Figure 2. Map of NINO Region

Source:https://www.climate.gov/sites/default/files/Fig3_ENSOindices_SST_large.png

Figure 3. Sea surface temperature anomalies (April, 2018)

Source: http://www.bom.gov.au/climate/enso/wrap-up/archive/20180508.ssta_pacific_monthly.png

April 2018 sea surface temperature departure from the 1961-1990 average.