Mercury increases marginally, clear days likely to lead to colder nights

New Delhi Residents woke up to a relatively warmer morning on Saturday, categorised a ‘cold day’, after four days ‘severe cold’ days. The maximum temperature recorded

New Delhi Residents woke up to a relatively warmer morning on Saturday, categorised a ‘cold day’, after four days ‘severe cold’ days. The maximum temperature recorded was 18 degrees Celsius, 3 degrees Celsius below normal, and the minimum temperature recorded was 9.5 degrees Celsius, 1 degree Celsius above normal.

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There was dense fog in the early morning hours with zero visibility at Palam before 8am, only 100 metres and 200 metres at Palam and Safdarjung stations, respectively, after 8am. Meteorologists said severe cold conditions were relieved because of sunshine for a few hours in the day. Isolated drizzles were also reported from different parts of the city.

“We are expecting the minimum temperature to decline further because the sky is clearing up, low clouds are disappearing and there will be sunshine. On clear days, nights will be colder because of radiational cooling. There will be dense fog in the morning hours also because of moisture and cold weather,” said Kuldeep Shrivastava, head of regional weather forecasting centre.

Radiational cooling is referred to a significant drop in the night temperature as earth surface radiates heat away.

On Friday, Delhi recorded a minimum temperature of 6.4 degrees Celsius, two units below normal and a maximum temperature of 17.5 degrees Celsius, five units below normal, at the Safdarjung station. Until Friday, there were four ‘severe’ air quality days last week.

Pollution levels in the city continued to remain in the ‘severe’ category with an Air Quality Index of 418. “The pollution levels are expected to remain in the same category in the next three to four days, since the temperatures are likely to remain low and the wind speed will improve, but marginally. We are seeing ‘severe’ air quality because the wind speed is less than 8 kmph and moisture is turning the particles heavier, making it harder to disperse,” Shrivastava added.

IMD’s Saturday bulletin said ‘severe cold’ conditions were observed in some pockets over east Uttar Pradesh and Bihar; over Gangetic West Bengal and west Uttar Pradesh; northwest Rajasthan and ‘cold day’ conditions in some pockets of Punjab. “Severity of ‘cold day’ conditions over north Indian plains has reduced significantly. ‘Cold day’ conditions at isolated pockets are likely over Punjab, Haryana, Chandigarh, Delhi, west Uttar Pradesh and Bihar during next two days,” it stated.