The city was cloudy in phases throughout Friday but there was no rain.
The clouds came from Cyclone Mocha, which was on the central Bay of Bengal on Friday afternoon. From a tiny speck on the southeast Bay of Bengal six days ago, it has intensified into a monstrous storm with a diameter of around 600km, said Met officials.
In Kolkata, the cloud cover dragged the Celsius down. However, it also led to an increased level of humidity, which resulted in more sweating.
“Some clouds from the outer edge of the storm are breaking away as it moves. Some of the breakaway clouds reached the Bengal coast. It was because of these clouds that the sky was cloudy in Kolkata,” said G.K. Das, director, India Meteorological Department, Kolkata.
Thanks to the clouds, the maximum temperature dropped in Kolkata and its surroundings, as well as in the districts.
The Met office recorded a maximum temperature of 35.6 degrees in Alipore, almost three degrees lower than the day before.
Bankura and Birbhum, where the Celsius breached the 42-degree mark multiple times in the past few days, recorded maximum temperatures of 39.5 and 38 degrees, respectively, on Friday.
The slide in the mercury was largely offset by a rise in the humidity level. The minimum relative humidity — a marker of the moisture content in the atmosphere during the driest part of the day — was close to 50 per cent in Kolkata on Friday.
Similar breakaway clouds and the increased humidity levels hold the key to any temporary relief from the heat assault, the Met office has said.
“On Saturday and Sunday, more such clouds and some moisture-laden easterly winds are expected to reach Bengal as the cyclone barrels towards the Bangladesh-Myanmar coastline. But the moisture has to be in the higher levels of the atmosphere for a spell of thunderstorm. On Friday, the clouds were not strong enough to cause thunderstorms because they were at a lower level,” said Das of IMD, Kolkata.
“There is a 30 per cent chance of thunderstorms in Kolkata on Saturday,” he said.
But whether clouds reach Bengal or not, Mocha is gearing up to reach its peak intensity in the deep sea.
The very severe cyclonic storm moved nearly north-northeastwards with a speed of 13kmph and lay over the central Bay of Bengal, 870km from Cox’s Bazar (Bangladesh) and 800km of Sittwe (Myanmar), around 2.30pm on Friday, a Met bulletin said.
“It is very likely to move north-northeastwards and intensify further into an extremely severe cyclonic storm over east-central Bay of Bengal on Friday night,” said the bulletin.
But it will lose some strength while still at sea, according to the forecast.
“It is likely to cross southeast Bangladesh and north Myanmar coasts between Cox’s Bazar (Bangladesh) and Kyaukpyu (Myanmar), close to Sittwe (Myanmar) around noon of 14th May as a very severe cyclonic storm with a maximum sustained wind speed of 150-160kmph gusting to 175kmph,” the bulletin said.