Very Strong El Niño and the Forecast to Action Gap

Context

The World Meteorological Organization assessed the probability of the ongoing El Niño continuing until February 2027 at nearly 100%, with the phenomenon expected to peak around December. India had already experienced a deficient southwest monsoon.

Key Highlights

• Strengthening El Niño: The phenomenon was reported to be firmly established and intensifying rapidly.
• Monsoon Deficit: India’s southwest monsoon ended with an approximately 13% rainfall deficit and drought was declared in several States.
• Impact on Pacific Circulation: El Niño weakens or reverses the normal patterns of Pacific trade winds and ocean temperatures, affecting the Walker circulation.
• Potential Global Effects: These include reduced rainfall in India and Australia, flooding in western South America, higher global temperatures, and pressure on crop prices.
• Multiple Influencing Factors: The relationship between El Niño and the Indian monsoon is significant but not deterministic. The Indian Ocean Dipole, snow cover, local atmospheric circulation, and intra seasonal variations also influence rainfall.
• Forecast to Action Gap: Weather forecasts become useful for the public when they are translated into practical, district level decisions.

Key Concepts

• ENSO (El Niño Southern Oscillation): A coupled ocean atmosphere phenomenon in the tropical Pacific that includes El Niño, La Niña, and neutral phases.
• Walker Circulation: An east west atmospheric circulation system over the tropical Pacific Ocean.
• Indian Ocean Dipole (IOD): A difference in sea surface temperatures between the western and eastern equatorial Indian Ocean.
• Seasonal Forecast: A probabilistic outlook indicating the likelihood of future weather conditions rather than providing a certain prediction for every location.

Way Forward

• Prepare and activate district level crop advisories based on updated weather forecasts.
• Develop water budgets to manage available water resources during deficient rainfall.
• Strengthen heat and disease surveillance systems.
• Maintain fodder reserves to support livestock during drought conditions.
• Provide employment support in drought affected areas.
• Establish predefined triggers for relief measures based on observed conditions and revised forecasts.