Cyclone Kyant loses steam, rain alert remains

Pedestrians caught in a spell of rain in central Calcutta on Thursday afternoon.
Picture by Bishwarup Dutta

TT, 27 October 2016: Cyclone Kyant lost steam to become a deep depression as it moved away from Calcutta on Thursday but left in its wake a trough that can bring rain to the city over the next two days.

The Met department expects isolated light to moderate rain on Friday and stray light drizzle on Kali Puja on Saturday. Diwali on Sunday is likely to be dry.

Meteorologists expect the storm to weaken further and turn into a depression by Friday morning and a low-pressure area later in the day.

"Kyant has weakened prematurely but that does not rule out rainfall in Calcutta," said Ganesh Kumar Das, director, India Meteorological Department, Calcutta.

"The cyclone has catalysed the formation of a trough of low pressure that is stretching from Bangladesh to south Bengal across the Bay of Bengal.... So, even though the storm has lost steam before it was supposed to, there is no change in the rainfall forecast for Calcutta."

A trough of low pressure is an imaginary line that draws air towards itself. The position of the current system is such that it is drawing moisture inland into Calcutta from the Bay of Bengal, creating a condition conducive to rain.

The city witnessed rain on Wednesday night and early on Thursday, when Kyant was still a cyclone. The Met office recorded 26.3mm of rain over 24 hours till 5.30pm on Thursday.

This was the first time it rained in Calcutta in 16 days since Dashami, when the city received 12.1mm of showers.

Under the impact of cloud cover and rain, Thursday recorded a maximum temperature of 30.1 degrees Celsius, a notch below normal and a couple of degrees below Wednesday's maximum.

The inflow of moisture has, however, pushed up the humidity levels. On Thursday, the minimum humidity was as high as 75 per cent, almost twice as much as it was a week back and 20 notches up from Wednesday's count.

The excess water vapour in the air is stalling the cool wind from Bihar and Jharkhand, which is why the minimum temperature in the city has been on the higher side. The lowest the mercury dipped on Thursday was 24.2 degrees, a notch above normal.

"As the wind from the west have been stalled, the nip in the morning air is missing. Even after the trough dissipates it might take a while for the wind to change course and the hint of chill to return," a weather scientist said.