February 1, 2021 12:03:21 am
Delhi recorded seven cold wave days this January, highest in the same period since 2008, when there were 12, as per the India Meteorological Department (IMD).
In January 2020 and 2019, the city had recorded only one cold wave day and none in 2018, as per IMD data.
The average mean minimum temperature this month was seven degrees Celsius, one degree less than what it was in January 2020.
Detailing the reasons behind the cold wave, Kuldeep Srivastava, head of the IMD’s regional weather forecasting centre, said, “Only one western disturbance affected the plains of northwest India this month, which meant there were more cloudless nights.”
A western disturbance is a weather pattern associated with sudden rain and snow in northwest India. It changes wind patterns and reduces radiation from the earth’s surface to the atmosphere at night time due to cloud cover, causing temperatures to rise.
Srivastava added, “We also had northwesterly winds blowing over Delhi-NCR from ice clad areas (in the Western Himalayas).”
A cold wave is declared when the minimum or night time temperature falls below 4 degrees Celsius. Another criteria is when it falls to 10 degrees Celsius or lower and the departure from normal temperature is 4.5 degrees or higher.
On January 1, the minimum temperature had dipped to 1.1 degrees, lowest for the month since January 8, 2006, when it was 0.2 degrees. On Sunday, it was 3.1 degrees Celsius.
The IMD has forecast that temperatures would rise in the coming days.
Srivastava said, “Over Delhi-NCR, an approaching Western Disturbance will cause a thunderstorm with light rain on February 4 and 5.”
Minimum temperature is forecast to rise up to 10 degrees by February 4 before falling again.
At the same time, maximum temperature is forecast to reach 26 degrees Celsius.
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