Minimum temperature of 15.4°C in Pune, brings chill feel in ‘cruel’ April

PUNE: The minimum temperature of the city suddenly plunged on Thursday morning, springing a pleasant surprise in the summer month April.
The mercury dropped to 15.4°C in Shivajinagar on Thursday morning. Only twice did the minimum temperature dip to this level in the second-half (last 15 days) of April in the last decade — 15.8°C on April 16, 2013, and 15.3° on April 25, 2015.The minimum temperature in Shivajinagar on Thursday was thus the lowest minimum for the last 15 days of April after 2015.
The past decade registered such low minimums in April, but they were usually recorded during the first 10 days of April and not in the last fortnight of the month.
In Lohegaon, the minimum temperature dipped to 17.3°C on Thursday from Wednesday’s 21.3°C. The minimum temperature in Shivajinagar on Wednesday morning was 22.3°C.
Just a couple of nights ago, the night temperature in the city was over 23°C. The mercury plunge was unexpected, stated Met department officials. They were not expecting the temperature to fall below 19°C.
A look at temperatures in many parts of the state on Thursday morning showed that the minimum temperature was less than normal by one to four degrees or more. Mumbai (Santacruz) recorded minimum temperature of 19.6°C on Thursday — 4.6 degrees below normal. It was a significant dip from Wednesday’s 25°C.
The mercury slipped below 20°C in several places in Maharashtra on Thursday. Ahmednagar, Satara, Mahabaleshwar, Nashik, Amravati, Gondia and Akola recorded a significant drop in minimum temperature on Thursday, but Pune was the coolest in the state. Shivajinagar’s minimum temperature on Thursday morning was also less than that in Delhi, Jammu, Dehra Dun and Amritsar.
Anupam Kashyapi, head of weather, India Meteorological Department (IMD), Pune, said the drop in the temperature was unusual and unexpected. “Several factors were responsible for the sudden fall in the night temperature in northern Maharashtra (in north Madhya Maharashtra, north Konkan and Goa and north Marathwada). We had clear skies after several days on Wednesday night with no cloud cover, coupled with a 20-25% drop in humidity levels in comparison to what we were seeing during the thunderstorm days,” said Kashyapi.
These were not the only reasons for the drop in the minimum temperature. The city’s elevation (altitude) also contributes to the low minimum temperature. Moreover, the city is once again witnessing cool, northerly wind flow from colder regions in north India.
“Jammu and Kashmir and Himachal Pradesh, among others recently witnessed rain and snow. The northerly winds are thus passing through those colder regions and coming into parts of Maharashtra. The lack of clouds is also causing unhindered passage,” he said.
Also, the recent spell of rain temporarily cleared pollutants and aerosol particles from the air.
“These aerosols, along with cloudy skies, usually trap long wave radiation emitted from the earth at night. Hence, a high night temperature is associated with cloudy skies and pollutants. On Wednesday night, we had clear skies and the aerosols were also cleared due to the rain activity in the city. Both these factors ensured maximum escape of long wave radiation into the atmosphere, causing a significant cooling effect,” said Kashyapi.