Rain spares Kolkata

KOLKATA: Kolkata remained cloudy even as the threat of showers loomed large. But the cyclonic circulation that had been brewing over Madhya Pradesh didn’t move significantly till late evening and skies gradually cleared up as the day progressed. Weathermen, however, predicted that the system could move late into the evening resulting in rain on Tuesday. Kolkata recorded a minimum temperature of 21.1 degree Celsius on Monday – a jump of five degrees in 24 hours.

“The circulation was expected to reach Jharkhand on Monday morning which would have triggered rains during the day. Buy it hardly moved holding up the showers. Since the system has formed far away from the Bay of Bengal – which is feeding moisture into the system – convective clouds didn’t gather satisfactorily. It resulted in the showers not materializing on Monday,” explained Regional Meteorological Centre (RMC) director GK Das.

He, however, predicted the possibility of an intense spell once the system moves and reaches Gangetic Bengal. “The movement of the circulation will depend on the prevailing wind speed. If it gets enough wind in its tail, the system can reach Kolkata in 3-5 hours. We expect one good spell and the rains could last till Tuesday evening,” Das said.

Convective clouds form when rising air through expansion cools to the point that some of the water vapour molecules clump together faster than they are torn apart by their thermal energy. These clumping molecules condense to form could droplets. “The closer a system forms to the sea, the faster and easier it is for the convective clouds to form. This system was generated at a little greater distance than ideal but it still has the potential to generate heavy showers,” said Das.

Even though an RMC bulletin on Monday evening said rain and thundershowers were likely to lash Kolkata, Howrah, North and South

24 Parganas

late on Monday evening, RMC officials said chances of a thundershower were low.