Some parts of Calcutta received light rain on Wednesday.

The spread and intensity of the showers are likely to go up from Thursday, according to the Met forecast.

“Conditions are becoming favourable for the advancement of southwest monsoon into some more parts of central and adjoining east India around June 14,” a Met report said.

“The monsoon currents had been weak on the Bay for a long time. Now, the conditions are changing. However, it is still not clear when it will reach Calcutta . But the monsoon currents on the Bay are growing stronger,” said a Met official in Calcutta.

The currents are already strong on the Andaman Sea and neighbouring areas.
On the north Bay, which is closer to Calcutta, the currents are still relatively weak. But they will also gain steam in the coming days, said Met officials.

“An upper air cyclonic circulation lies over west-central Bay of Bengal off the north Coastal Andhra Pradesh... The upper air cyclonic circulation over north Odisha and its neighbourhood... has become less marked,” the Met report said.

Another system is likely to take shape over the Bay between June 13 and 19 and might trigger uniform rain across south Bengal. There is a possibility that the fresh system propels the southwest monsoon into south Bengal, said the Met official.