Coastal Karnataka records season’s first heatwave

Day temperatures shot up to around 40°C in the region on Saturday even as large parts of the country recorded near normal temperatures.

Two coastal districts of Karnataka, Uttara and Dakshin Kannada, surprisingly recorded the season’s first heatwave in the country from Friday to Monday due to an anticyclone over the Arabian Sea in an area where cool sea breezes moderate temperatures even in peak summer.

Two stations in Uttar Kannada district, Karwar and Honavar, recorded 40.2 ( plus 6.8) and 39.4°C (plus 6.7), respectively. (HT FIle)

Day temperatures shot up to around 40°C in the region on Saturday even as large parts of the country recorded near normal temperatures. Two stations in Uttar Kannada district, Karwar and Honavar, recorded 40.2 ( plus 6.8) and 39.4°C (plus 6.7), respectively.

On Sunday, Goa recorded a maximum temperature of 37.1°C , 5 above normal; Mumbai 38.1 degrees, 5 above normal; Honavar 37.3°C , 5°C above normal; and Kannur 37.6°C , 4 above normal. Mumbai recorded a minimum temperature of 25.4°C, also 5°C above normal.

Anticyclonic conditions lead to subsidence of air and warming over the west coast. Heatwaves are rare over southern coastal regions, M Mohapatra, director general, IMD said. “These areas do not fall in the core heat wave zone. This time coastal Karnataka recorded high temperatures but fortunately it was a marginal heatwave, and temperatures have started falling again. In March during some years, heatwaves have been recorded over coastal Odisha and Andhra Pradesh, but not these regions.”

“It is unusual for areas along the west coast to record heatwaves, especially in March,” said Mahesh Palawat, Vice President, climate change and meteorology at Skymet Weather. “On the east coast, Odisha and Andhra Pradesh record heatwaves, but only during late April and May.”

The unusual heatwave on the west coast was because the sea breeze was affected and winds were blowing from the interior parts of the country, Palawat explained.

“This is mainly an impact of the anticyclone, which also led to very high temperatures over the west coast in February,” he added. “From today, we are expecting the heatwave to be relieved over coastal Karnataka.”

Maximum temperatures are in the range of 35-38°C over many parts of Gujarat, Maharashtra, southern peninsular India, Vidarbha, Chhattisgarh, Odisha, Jharkhand and Gangetic West Bengal; in the range of 31-35°C over parts of Rajasthan, Madhya Pradesh and Bihar; in the range of 28-31 degrees over Punjab, Haryana, Chandigarh, Delhi, Uttar Pradesh and the northeastern states, the weather bureau said.

Maximum temperatures are above normal by 2-4°C over parts of northwest, east and northeast India and along the west coast, and near normal over the rest parts of the country.

“Due to a change in the wind direction and the western disturbance impacting the western Himalayan region now, heatwave conditions have relieved from coastal Karnataka. For the next few days, we do not expect a steep rise in maximum temperatures,” said Mahesh Palawat, vice president of climate change and meteorology at Skymet Weather Services, a private forecaster.

“This March heat wave was mainly a result of the anticyclone that was persisting over Arabian Sea,” he said. “We have to keep a watch on maximum temperatures from March 10 onwards.”

Temperatures began surging in mid February over parts of the country, especially in states along the western coast, with days being a whopping 5-10°C warmer than normal in parts of Gujarat, Maharashtra, Goa and Karnataka. But from February end, consecutive western disturbances helped bring down maximum temperatures over west and northwest India. Among the stark temperatures recorded was the 40°C in Bhuj on February 15, some 10°C higher than normal.

A heatwave is declared when the maximum temp is over 40°C over the plains, over 37°C over coastal areas and over 30°C over hilly regions. During a heatwave, the maximum temperature is 4.5 to 6.4°C above normal.

Heatwaves generally occur over the plains of northwest India, central, east and north peninsular India during March to June.