IMD Predicts Below Normal Monsoon Amid Possible El Nino Impact
Forecast Overview
In a concerning development for India’s agricultural sector and rural economy, the India Meteorological Department (IMD) announced on Monday that it anticipates a ‘below normal’ southwest monsoon for the upcoming season from June to September. This prediction comes against the backdrop of increasing risks associated with El Nino, a climatic phenomenon known to lead to reduced summer rainfall across India.
Mrutyunjay Mohapatra, the IMD chief, detailed that the seasonal rainfall is expected to be approximately 92% of the long period average (LPA) with a model error margin of plus or minus 5%. The LPA is calculated based on data from 1971 to 2020, which records an average seasonal rainfall of 87 centimeters. Rainfall measurements between 90% and 95% of this average are classified as ‘below normal.’
Probability of Deficient Rainfall
The IMD’s forecasting indicates a 31% probability of ‘below normal’ rainfall while presenting a 35% likelihood of ‘deficient’ rainfall, which is defined as below 90% of the LPA. This analysis suggests an elevated risk of a notably lower-than-average monsoon throughout the country.
Such deficient rainfall is expected to have a detrimental impact on irrigation and agricultural practices, particularly for the kharif and rabi crops. The IMD will provide a more detailed update on the spatial distribution of rainfall within the season towards the end of May. However, preliminary forecasts indicate a strong likelihood of below normal precipitation affecting the ‘monsoon core zone’, predominantly located in central and western India, which relies heavily on monsoonal rains for agricultural operations.
Impacts on Agriculture and Water Supply
The anticipated below normal rainfall could significantly influence irrigation practices, drinking water availability in arid and semi-arid regions, reservoir capacity, and the potential for hydro-power generation. This forecast emerges at a time when farmers are already contending with heightened input costs, particularly for diesel and fertilizers, exacerbated by ongoing geopolitical tensions in West Asia.
Furthermore, insufficient rainfall during this period could adversely affect the cultivation of summer-sown crops (kharif) and winter crops (rabi), as the soil moisture and water availability for reservoir irrigation become critically low. This situation poses a threat to overall food grain production, even as the Indian agricultural sector has implemented various strategies to enhance drought resilience over the years.
El Nino and the Indian Ocean Dipole
As the IMD noted, the potential emergence of El Nino conditions—characterized by the warming of ocean surfaces in the central and eastern tropical Pacific Ocean—suggests a heightened risk of reduced rainfall in the latter half of the monsoon season (August to September). This aspect raises broader concerns regarding agricultural output during this crucial period.
However, there may be a positive note in the forecast concerning the Indian Ocean Dipole (IOD). Mohapatra mentioned that conditions in the Indian Ocean could become favorable around August. A positive IOD typically contributes to increased rainfall, which might mitigate some negative effects brought on by El Nino in the second half of the monsoon season. Presently, neutral IOD conditions are prevailing, but forecasts indicate a shift toward positive IOD conditions towards the end of the southwest monsoon season, albeit with a cautionary note on the unpredictability of IOD developments.
