A mass of moist air originating in north India and blowing east along the Ganga had condensed into advective fog last Wednesday and Thursday. This fog — distinct from the normal winter fog — not only prevented sunlight from reaching the ground but also ensured that the flow of the North Wind was closer to the ground.
“A western disturbance over northern India has temporarily restricted the flow of the North Wind,” an official of the India Meteorological Department said.
The flow of the already low-intensity North Wind is also being obstructed by the incursion of moisture into the air. “Calcutta is now receiving winds from the opposite direction,” a weather scientist said.
The easterly wind is likely to die down on Monday, which is why there is a possibility of the minimum temperature dropping again on Tuesday.
The cold feeling is likely to stay till at least Thursday, though the Celsius is unlikely to dip below 13 degrees.
Met officials said it was difficult to predict if the weather would get colder than it has been this season so far. “A sub-10 reading doesn’t look possible in the rest of January because of the frequency and trajectory of the western disturbances expected to hit north India,” the IMD official said.
If the Met office is proved right, there is little chance Calcutta will experience a meteorologically “chilly” day this winter. The temperature hasn’t dipped below 10 degrees Celsius in February in the last 10 years.
This season’s lowest temperature so far is 11.3 degrees Celsius, recorded on January 9. On the same day last year, the Celsius had plunged to 9 degrees, a 24-year record.