The ENSO outlook remains at El Nino ‘Alert’. In the last 4 weeks, equatorial sea surface temperatures (SSTs) were above average across the central and eastern Pacific Ocean. Near-average SSTs were present in the Western Pacific Ocean. SSTs near Ecuador and Peru remained strongly above average.
ENSO: Nino indices have risen further, albeit marginally and are above the threshold mark of 0.5°C. The principal oceanic indicator, Nino 3.4 has crossed 1°C for the first time after 25th March 2019. In between, because of the triple dip La Nina, Nino 3.4 had remained mostly negative. Nino 1+2 has now reached all-time high of 3.4°C, since Jan 2015.
The SST anomaly for Nino 3.4 during Mar-May 2023 season was +0.22°C. For the month of May and June 2023, the average Nino 3.4 index value was 0.47°C and 0.9°C respectively. The SST average for Nino 3.4 during Apr-May-Jun 2023 season was 0.5°C, touching the threshold mark. These values are strongly suggestive of El Nino conditions in the tropical Pacific.
IOD: Indian Ocean Dipole is currently neutral. The IOD index value for the week ending July 16, 2023, was -0.12°C, which is within neutral bounds (between -0.4°C and +0.4°C). The index value has remained -VE neutral for the 4th consecutive week. Also, there has been a mismatch between the actual and model projected values.
MJO: Madden Julian Oscillation has largely remained disorganized for the last 4-5 weeks. It continues to retain a low amplitude. Models indicate potential for reemergence of MJO activity over the Maritime Continent and Western Pacific in Phase 5&6, in the coming weeks. Situation is quite favourable for tropical storm formation over the Western Pacific Ocean. Indian seas do not find any trigger in weather activity on account of MJO. Likely tropical storm formation in the Western Pacific during fag end of July may not augur well for the continuation of active monsoon conditions.
The Pacific Ocean and the atmosphere have yet to become fully coupled, as is normally desirable during El Nino events. However, the confidence level in the occurrence of El Nino has increased and a strong El Nino event is likely, with a peak around the autumn season of the Northern Hemisphere. Despite the El Nino conditions and negative neutral IOD, the monsoon seems to be driving on its own energy.