Cooling of equatorial Pacific Ocean has ceased. Triple dip La Nina has finally ended. Simultaneously, warming of Pacific, both surface and sub-surface has commenced. Positive Sea Surface Temperature (SST) anomalies have strengthened in the eastern and central Pacific and expanded westward. Nino 3.4 region, primarily earmarked for monitoring, assessing and predicting ENSO has crossed over to +VE anomaly, after a long gap of 34months, since May 2020. El Nino is the phase of ENSO, where waters in the Pacific Ocean are warmer than the average and breach the threshold mark of +0.5 degree. Neutral conditions are likely to persist through the Northern Hemisphere spring and early summer 2023.
La Nina is followed by ENSO neutral or El Nino. Statistical records are the testimony for an equitable chance of either of them. Monsoon rainfall mostly remains below normal even during neutral years, preceded by La Nina. However, the El Nino years following La Nina events invariably lead to insufficient rainfall. Quite a few of these end up in a drought.
Since 1950, there have been 8 El Nino years preceded by La Nina. Two of these plunged in to severe drought in 1972 and 2009. Contrarily, 2 such years in 1957 and 1976 observed normal rainfall during the season.
Last El Nino was observed in 2018. Monsoon rainfall was highly inadequate (90.6% of LPA). It narrowly everted mild drought. El Nino projections based on numerical models are considered to be marred with 'spring predictability barrier' till early April. Supposedly, more reliable and authentic forecast emerges during later half of April/May.
Atmospheric and oceanic indicators so far, predict an evolving El Nino till July 2023 and converting to full fledged El Nino event in the later months. El Nino conditions in the recent past like 2009, 2014, 2015 & 2018 spoiled the monsoon season. The corrupt rainfall, if any, is bound to impact adversely Kharif crop yield and the agriculture sector as a whole.
