Heatwave to intensify in north India, south to see rainfall: IMD, Climate Central warn

As the scorching heat engulfs the country, the India Meteorological Department (IMD) cautioned that Delhi, Punjab, and Haryana will experience a heatwave from May 18 to May 20.

As per IMD, a heatwave is declared when the maximum temperature surpasses 40°C in the plains; 37°C in coastal regions and 30°C in hilly regions, even as the deviation from normal is between 4.5°C and 6.4°C above the average maximum.

This will be followed by other parts of northern India and Bihar experiencing similar conditions over the next five days, the weather forecasting agency added.

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At the same time, temperatures in other parts including northwest India and Gujarat will go up to two to three degrees. This increase in heat is because of weakening western disturbances which is a weather pattern responsible for keeping the temperature down.

“There is no immediate chance of rain. There is also a subsidence of hot air, which is heating the surface due to an anticyclone over northwest India. Soon, there will be an advection of hot air towards UP and Bihar also. Conditions will remain very hot for the next seven days,” said M Mohapatra, director general of IMD.

Advection is the transfer of heat through the horizontal movement of air which is more significant than the vertical movement. In the middle latitudes, day-to-day variation in weather is caused by advection only.

This comes with the increased peril of heat-related illnesses because of prolonged exposure to the sun. Moreover, people doing heavy work or having high health concerns are also said to be cautious of it.

"Forecasts indicate that western India, including the National Capital Territory of Delhi, will experience a period of intense heat from May 18-20, 2024. The event will include unusually warm nighttime temperatures, which can intensify the risk of heat-related illness and death," the Climate Central group said in an analysis.

Human-caused climate change made these conditions much more likely, Climate Central said.

“There is an anticyclone over West Rajasthan and Pakistan, causing the incursion of hot air from Balochistan and Thar desert. Heatwaves have started in parts of Rajasthan and some parts of Delhi also met the heatwave criteria on Wednesday. The area impacted by heatwaves will increase,” said Mahesh Palawat, vice president, of climate and meteorology at Skymet Weather.

Contrary to this, the weather in south of India has been better with instances of rain across peninsular India.

This is due to the cyclonic circulation over Kanyakumari in Tamil Nadu and the adjoining southern fringes of the state.

This circulation outlined the likelihood of widespread light to moderate rainfall alongside thunderstorms, lightning and gusty winds over Tamil Nadu, Puducherry, Karaikal, Kerala, Mahe, Lakshadweep and south Karnataka over the next seven days.

IMD also cautioned regarding flooding across Tamil Nadu.

(With inputs from agencies)