A sharp spell of rain struck Calcutta on Thursday afternoon in between occasional drizzles throughout the day.

The sun also came out in the afternoon — the first bright stint the city had in nearly three days.

The afternoon shower, which reduced visibility and slowed traffic, was caused by the active monsoon currents, said Met officials.

Friday and Saturday are expected to be drier than Thursday, said a Met official.

“One or two spells of light rain are not ruled out. The sky should be sunny in parts,” the official said.

The intensity and spread of the rain are expected go up from Sunday and Monday is most likely to see formidable rain in Calcutta, he added.

The system that was behind the downpour between Tuesday night and Wednesday morning and the persistent showers throughout the rest of Wednesday had moved
close to Jharkhand by Thursday morning, said a Met bulletin.

“The low-pressure area over Gangetic West Bengal and adjoining Jharkhand lay over south Jharkhand and neighbourhood at 8.30am on Thursday,” the bulletin said.

“The monsoon trough at mean sea level now passes through Suratgarh (Rajasthan), Bhiwani (Rajasthan), Aligarh (Uttar Pradesh), Banda (Uttar Pradesh), Daltonganj (Jharkhand), Digha and thence southeastwards to northeast Bay of Bengal,” the weather bulletin said.

A Met official said: “The low-pressure area has moved over Jharkhand. The intensity of rainfall will go down over south Bengal. However, because of the presence of monsoon flow, light to moderate rain may happen in several areas.”

The Met office recorded around 17mm of rain in Alipore between 8.30am and 8.30pm on Thursday.

Most of it happened between 3pm and 4pm.

The Met forecast for south Bengal for Friday and Saturday is “light to moderate rain at many places”.

On Sunday, light to moderate rain is likely in “most places” in south Bengal.

On Monday, heavy rain is likely in Purulia, North 24-Parganas and South 24-Parganas, the bulletin said.