Temperatures have begun surging in parts of the country, especially in states along the western coast, with days being a whopping 5-10 degrees Celsius warmer than normal in parts of Gujarat, Maharashtra, Goa and Karnataka – a trend that meteorologists called “very unusual” for this time of the year.
The warming seems to be as bad, if not worse, than the conditions in 2022, when much of India skipped spring season conditions to enter summer-like temperatures within days of the winter ending.
The spring heatwave last year led to at least 90 deaths across India and adjacent Pakistan, triggered a glacial lake burst in northern Pakistan, and led to forest fires in the hills of Uttarakhand. March 2022 eventually had the highest-ever average temperature recorded nationally. It also hit India’s wheat output.
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“This is very unusual. Last year we saw maximum temperatures spiking in March, this time it’s even earlier in February,” said Mahesh Palawat, vice president, climate change and meteorology at Skymet Weather, a private weather forecaster.
Among the stark temperatures recorded was the 40°C in Bhuj on Wednesday, some 10 degrees higher than normal. On Thursday, such a high departure from normal was recorded in Bikaner in Rajasthan, where the maximum was 36.8°C. In J&K, the deviations were 7-9 degrees above normal. The Capital recorded a maximum temperature of 29.8°C, 6 degrees above normal.
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In addition to the increased risk of forest fires and rapid glacier melt, such unusual temperatures could have a significant economic impact: winter crops may need to be harvested sooner than normal, and the warm, dry conditions could leave irrigation reservoirs depleted.
Palawat said at fault is a climatic phenomenon known as an anti-cyclone that has formed over the northeast Arabian Sea, sending dry and hot winds from Sindh and Balochistan westwards, over parts of India.
“The temperatures are also high in the hill regions but that is also because very feeble western disturbances are not bringing adequate rain and snow to the Western Himalayan region,” Palawat added.
A western disturbance, or WD, is the incursion of moisture laden winds that originate in the Mediterranean region – these usually bring rain to the plans in the northwest and snow to the Himalayas, which help create cool winds.
“In November and December there were hardly any WDs so the hills remained mostly dry, in January we saw some good weather activity due to strong WDs but February has again been dry and warm,” he added.
A second expert explained that the lack of cloud-drawing WDs means the plains get more sunshine, absorbing more energy and, thus, becoming hotter – a phenomenon known as solar insolation. “We are keeping a close watch on Gujarat and Saurashtra. Last year also in spring months we saw that the impact of WDs was less leading to higher solar insolation over the plains,” said Naresh Kumar, senior scientist at India Meteorological Department.
He added that the anticyclone has meant that the winds blowing over these states are coming from the plains, blocking out the usual sea breeze from the Arabian Sea that has a cooling effect. “This is why maximum temperatures have increased quite a bit over the western region. There is a rising trend in temperatures over the northwestern plains also now,” he added.
A third expert said the spike in heat could be transitory, but admitted that the patterns are noteworthy. “Every spring, anti-cyclones form over the western region and over Bay of Bengal but this time the anti-cyclone over Arabian Sea has formed early, bringing dry, warm air. The soil is also dry, so there is a positive feedback mechanism making temperatures spike over many parts of the country. Hopefully this phase will end soon and temperatures will fall once again,” said M Rajeevan, former secretary, ministry of earth sciences.
What is different this year is the prediction that El Nino conditions will take hold in the global weather. “This year being a transition year to El Nino conditions, India should be fully prepared for an increase in severity and frequency of heat waves. The preparations should have started by now,” he said.
HT reported on February 10 that early data shows a high probability of the El Nino climate pattern this year, prompting experts to warn of a potentially warmer summer, although they admit that it’s premature to assess its impact on the annual monsoon rains.
There is an almost 50% probability of El Nino conditions prevailing during summer months of June, July and August, and a 58% probability in July, August September according to the latest probabilistic estimates of the US National Oceanic and Atmospheric Administration (NOAA).
El Nino is characterised by an unusual warming of waters in the eastern equatorial Pacific; its opposite, La Nina is characterised by unusually cooler waters in the same area. Together, the phenomenon is called the ENSO (El Nino Southern Oscillation), and it has a high correlation with warmer summers and weaker monsoon rains in India.
In the next few days, minimum temperatures are very likely to rise gradually by 2-3°C over most parts of northwest and Central India and some parts of the east.