A strong ‘El Nino’ and northeast monsoon: What lies ahead for Tamil Nadu? | Explained

A powerful El Nino event and the northeast monsoon season hold significant importance for Tamil Nadu, as meteorologists closely monitor the potential impacts on the region's weather patterns. The exceptional warming of sea surface temperatures in the central and eastern Equatorial Pacific has already led to disruptions worldwide, and Indian monsoon is not spared.

Following the Southwest monsoon's retreat and rainfall deficits, El Nino's effect during the upcoming northeast monsoon is being closely observed by meteorologists. Models from various countries indicate a strong El Nino, with oceanic and atmospheric indicators supporting this assessment. The Niño 3.4 index, which measures sea surface temperature anomalies, has strengthened to an average of +2.51 degrees Celsius, well above the El Nino threshold.

Some models predict it could peak above +3.0 degrees Celsius in the coming months. Expected to persist until May or June 2027, this strong El Nino could significantly shift rainfall and temperature patterns globally and fuel extreme weather events. However, its impact varies depending on the region, season, and other climate drivers such as the Indian Ocean Dipole.

While strong El Nino conditions are considered favorable for a wetter northeast monsoon over southern Peninsular India, other factors like rising global temperatures and urbanization can amplify its effects. The period between 2023 and 2027 could be the warmest five years in history, with the Pacific expected to warm further and El Nino conditions likely peaking in winter and continuing into the next year.

The Tamil Nadu government has formed an Expert Advisory Committee to assess the potential impact of the strong El Niño and advise on preparedness and mitigation measures. The India Meteorological Department plans to release a seasonal forecast towards September, and an outlook forum for the northeast monsoon is scheduled for October 1.