The monsoon is likely to be gone from Calcutta within “two to three days”, the Met office said on Tuesday.
“The next few days are likely to be dry in most parts of south Bengal, including Calcutta. The conditions are becoming favourable for the monsoon’s retreat over the next two to three days,” said G.K. Das, director, India Meteorological Department, Calcutta.
After a rainy spell caused by a low-pressure area, the city and the rest of south Bengal have remained largely dry over the past couple of days.
Although the temperature is soaring, weather scientists have spotted the tell-tale signs of wind reversal that announce a seasonal change.
The minimum relative humidity — a marker of the moisture content in the air during the driest part of the day — on Tuesday was 49 per cent. Just a week ago, it was 84 per cent.
“It shows that the moisture-laden winds from the Bay are being replaced by winds from the north-western parts,” said a Met official.
Weather scientists generally treat three to four rain-free days as a prerequisite to announcing the withdrawal of the southwest monsoon.
A dip in the moisture content in the air is another marker of the end of the monsoon. The third, and most significant, marker is a reversal in the flow of winds.
The end of the monsoon is marked by the arrival of the winds from north India. The winds from the direction of the Bay gradually stop flowing into the city.
The maximum temperature on Tuesday was over 34 degrees Celsius, two notches above normal. The next few days are also likely to be warm.
“The line of withdrawal of southwest monsoon continues to pass through Raxaul (Bihar), Daltonganj (Jharkhand).... Conditions are favourable for withdrawal of southwest monsoon from some more parts of Bihar, Jharkhand and some parts of Gangetic West Bengal and Odisha during the next 2-3 days,” said the daily weather report issued by the Met office.