Wednesday was Calcutta’s coldest day in a fortnight, with the Celsius dipping as low as 12.8 degrees, but the chilly phase is unlikely to last beyond a day because of a cyclonic circulation developing over Bangladesh.
The last time the city was as cold was on January 16, when the Alipore Met office recorded a minimum temperature of 12.5 degrees Celsius.
Over the last week weather scientists had been predicting that the mercury would not drop below 13 this winter. But Wednesday proved them wrong.
“The Northerly wind was having a free run over the past two days as there was no weather system that could load the air with moisture and block the breeze. This led to a drop in the temperature,” said Gokul Chandra Debnath, director, India Meteorological Department, Calcutta.
“I shivered when I got out of bed this morning. It was extremely chilly, unusual for this time of the year, when I stepped out for a jog around 6am,” said Arijit Banerjee, 35, a resident of Salt Lake.
The chill, however, is likely to subside from Friday because of a cyclonic circulation before returning again at the start of next week.
“Satellite pictures on Wednesday have picked up a cyclonic circulation developing in the mid-levels over Bangladesh and its adjoining areas. The system will lead to moisture incursion that will impede the flow of the Northerly and cause the Celsius to rise,” said Debnath.
A cyclonic circulation in the mid-levels means it is at an altitude of 2-7km from the surface and is moderately strong.
The minimum temperature in Calcutta steadily came down from 15.3 degrees Celsius on Saturday to 12.8 on Wednesday (two degrees below normal) following the weakening of a low-pressure trough over central India that had been sucking away the cold wind.
Because of the cyclonic circulation, the minimum temperature is expected to climb back to a little over 13 degrees on Thursday and then by a degree each on Friday on Saturday.
After the cyclonic circulation dies down, expectedly between Saturday and Sunday, the temperature will start dropping once more, but not too steeply as a Western Disturbance now hovering over Afghanistan will enter Jammu and Kashmir by then.
“The Western Disturbance will initially make conditions humid in northern India. So the brisk breeze blowing to Calcutta and its surroundings from the north will lose its sting. The wind may intensify again around Wednesday,” said a weather expert.
With the day wind already dying down, the maximum temperature on Wednesday rose by three degrees to 24.9 from Tuesday’s 21.9. The maximum is likely to touch 26 degrees over the next two days.