Summer shocks!

A widespread heat wave has gripped most parts of northern, western and central India, including Maharashtra, New Delhi, Bihar, West Bengal, Odisha, Uttar Pradesh, Chhattisgarh, and Gujarat. Temperatures soared to past 40 degrees C (104 F) around Mumbai, Kolkata, Akola, Surat, Rajkot and New Delhi.

The unusual trend in weather patterns in March-end has made the national Capital hotter than expected. Palam observatory recorded maximum temperature at 40.6 degrees Celsius on Wednesday which is not only the highest of the year so far but also second highest in a decade. Safdarjung station, the central observatory and the main weather station, recorded maximum temperature at 40 degrees Celsius. According to a private weather forecast organisation, Skymet, both of these temperatures have settled seven degrees higher than the normal levels.

According to the India Meteorologist Department (IMD) website, the maximum temperature in Palam was 40.6 degrees, Lodhi Road 38 degrees, the Ridge 38.6 degrees and Ayanagar 38.2 degrees.

While temperatures have been above normal in these areas during this month, the intensity of the heat may climb to another level this week, putting people at risk of heat-related illnesses. Heat wave occurs when mercury shoots five degrees above normal.

The Met department has predicted about 52 per cent probability of above-normal maximum temperature in the core heat wave zone. The regions falling under the core heat wave zone are Delhi, Punjab, Haryana, Rajasthan, Himachal Pradesh, Uttarakhand, Uttar Pradesh, Gujarat, Madhya Pradesh, Chhattisgarh, Bihar, Jharkhand, West Bengal, Odisha and Telangana, and meteorological subdivisions of Marathwada, Vidarbha, central Maharashtra and coastal Andhra Pradesh.

Rajasthan, Maharashtra, and Odisha have recorded temperatures above 40°C. In some parts of Delhi and NCR, mercury touched 38 degree Celsius on Wednesday. Heat wave conditions in Delhi and NCR usually develop in the beginning of May, when the maximum temperature stays above the 40-degree threshold consistently, and starts to climb beyond the 45-degree mark.

Between March and May, the mean temperature in Delhi is expected to be over 1.5 degrees above normal, according to Met officials. Sunny skies and rising mercury levels have increased the summer heat to quite an extent. Until a few days ago, the minimums were settling close to the normal levels which is why the intense heat remained at bay.

Initially, the region witnessed northerly winds that kept the temperatures under check. However, the formation of a cyclonic circulation over Central Pakistan has led to the change in the wind direction.

At present, the winds are blowing from southwest direction and are traveling from Balochistan region wherein the temperatures are already peaking and are settling above the 42-degree mark.

“Clear and dry weather is likely to keep its hold over the West Rajasthan, West Madhya Pradesh, Chhattisgarh, Odisha, Punjab, Bihar, Uttrakhand, Uttar Pradesh, Jharkhand, Bihar, West Bengal, parts of Telangana and Maharashtra. This would lead to hot day conditions in these States. Thus, the next few days may see some rise in the mercury levels,” said officials of Met department. Delhi would witness a hot and dry day.

“Heat waves due to anti-cyclones in north India are a regular phenomenon during the April-May period, as are cyclones in the Indian Ocean. Occurrence in March is very rare, but possible”, said officials of Met Department.

“The weather in the country is likely to remain warmer than usual over the next three months due to rising temperatures across the globe,” Met Department officials further added.

The 2001-2010 period saw 98 heat waves across India, compared to 48, 45, 34 and 74 in the decades before, showing a marked increase in heat waves in the first decade of the 21st century. Around 4,620 deaths were reported in four years from 2013 to 2016. Some meteorologists attribute this to climate change. The pre-monsoon season is from March to May.