Summer resolution: On the IMD’s heat wave forecasts

Heatwave forecasts must be taken as seriously as monsoon warnings 

April 05, 2023 12:10 am | Updated 11:15 am IST

It is not exactly surprising when the India Meteorological Department (IMD) says that the summer months will be searingly hot. Last week, it proclaimed that most parts of the country are expected to experience above normal maximum temperatures during the “hot weather season” (March-May), barring parts of peninsular and northwest India, which would see normal or even below normal ‘maximum’ temperatures. This does not mean that northwest India, which sees temperatures well over 45°C, will be comfortable. ‘Above normal heatwave days, characterised by temperatures 4°-5°C above what is usual for that time in a region, are likely to occur over most parts of central, eastern and northwest India during the hot weather season,’ its forecast notes. A seasonal outlook issued by the IMD in March, on probable summer temperatures, too was on similar lines. However, what has changed in the last month is a greater certainty of an El Niño, or a warming of sea surface temperatures in the Equatorial Central Pacific, that is strongly associated with reduced rains over northwest India. Many El Niño years also see reduced monsoon rainfall during June to September and are often associated with drought-like conditions. The IMD’s official outlook says that ‘neutral’ (neither El Niño, or its converse, a cooling La Niña) conditions are persisting in the Pacific. The World Meteorological Organization’s outlook says that the chances of El Niño developing gradually increase from 15% in April-June, to 35% in May-July, and rise to around 55% during June-August. Later this month, the IMD is expected to announce its first forecast for the monsoon and this will hinge on the El Niño-La Niña development.

The purpose of forecasts is to give lead time to States to prepare. The National Disaster Management Authority has been issuing guidelines to States on preparing Heat Action Plans since 2016. Many States have prepared documents that detail measures and methods to deal with heat-related contingencies, that, as reports from the Intergovernmental Panel on Climate Change warn, are only poised to get worse. But, many of these recommendations are only on paper. An analysis by researchers at the Centre for Policy Research of such heat action plans found that most of them are not made to capture local context. For instance, only dangers from unusually high temperatures are evaluated and almost none from humidity and warm nights. Several plans are under-funded and lack legal backing. Heat wave forecasts should be taken as seriously as monsoon forecasts, and the Centre as well as State governments must play a more coordinated role in implementing these plans.

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