The warning for hot temperatures and heatwaves comes at a time when the El Nino event in the equatorial Pacific Ocean is in its waning phase
As the 2024 summer is approaching in the Indian subcontinent, the latest seasonal outlook issued by the India Meteorological Department (IMD) painted a grim picture for April, May, and June. Temperatures across India are already soaring, with four states having recorded either heatwave conditions or warm night conditions between March 27 and April 1.
These are Madhya Pradesh, Maharashtra, Rajasthan and Chhattisgarh.
The basic criteria for IMD to declare a heatwave is when the temperature of a place crosses 40 degrees Celsius in the plains. For coastal areas, this temperature value is 37°C and for the hills, it is 30°C.
These are the thresholds set by IMD for the declaration of heatwaves in India. Apart from this, the temperature of a particular day has to be above normal by at least 4.5°C for two consecutive days for a heatwave to be declared.
When the temperature crosses 45°C, the weather agency immediately declares a heatwave without considering the deviation from normal temperature for that particular place.
As per IMD’s outlook, except for isolated pockets in the east, Northeast, and northwest regions, the entirety of India may experience above-normal maximum temperatures throughout April, May, and June. The situation may not be any better during the night.
IMD's projections hinted at above-normal minimum temperatures also. This leaves little respite from the oppressive heat except for a few areas in the Northeast and northwest of the country.
A closer examination of the forecast revealed that the southern peninsula, central India, eastern regions, and the plains of northwest India were particularly vulnerable to above-normal heatwave days.
The states with the highest anomaly of days with heatwaves during April-May-June are Gujarat, Maharashtra, Rajasthan, Karnataka, Tamil Nadu, Madhya Pradesh, and Andhra Pradesh.
The warning for hot temperatures and heatwaves comes at a time when the El Nino event in the equatorial Pacific Ocean is in its waning phase.
IMD predicted that El Nino — generally responsible for warmer temperatures in many places around the world including India — may turn neutral within the seyason, with a possibility of La Nina conditions developing during the monsoon season.
The IMD's forecast didn't account for hot and humid weather, a combination that often creates more discomfort.
During a humid heatwave, the temperature felt by the human body or by other animals and plants is much higher. This happens even when the observed temperatures are lower than the thresholds because of relative humidity.
The oppressive heat is inevitable and the IMD's warning serves as a sobering reminder of the challenges posed by increasingly erratic weather patterns.
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