Monsoon set foot in Calcutta on Saturday but the rain was taken away by Jharkhand.

The volume and intensity of the rainfall in Calcutta could have been higher had a low-pressure system on Bay of Bengal, which propelled monsoon into most parts of south Bengal, entered land, said a Met official.

“The system on northwest Bay of Bengal is caught between two sets of winds. South-easterly winds from Bangladesh are blowing above the system and south-westerly winds from the Andhra coast are blowing under the system. As a result, the low-pressure area is not able to enter land. It is still on the sea,” said GK Das, director, India Meteorological Department, Calcutta.

Rain-bearing clouds are forming over Bangladesh and they are drifting to Calcutta, said Met officials. But instead of staying and eventually emptying themselves on the city, a bulk of the clouds are moving further away towards Purulia and Jharkhand because of the strong winds.

A depression over South China Sea is also attracting a fair share of the clouds formed because of the low-pressure area, said Das.

On Saturday, the sky was cloudy since morning and the blazing sun was missing in action. But the humidity level was high and conditions were sweaty until the showers started towards early evening.

Till 8.30pm on Saturday, the Met office recorded only 3mm of rain in Alipore. Some other areas of the city and its outskirts were wetter. Some pockets saw a spell or two at night.

“Southwest monsoon reached most parts of Bengal on Saturday, including Calcutta. The Northern Limit of Monsoon (NLM) passes through Bolangir, Bhubaneswar, Baripada (all three in Odisha), Purulia, Dhanbad (Jharkhand) and Darbhanga (Bihar),” said Das.

The Met office had predicted a wet spell over most districts of Bengal from June 11 to 15 under the influence of the system. Light to moderate rain was the forecast for most areas but a spell of two of heavy rain was not ruled out in the coastal areas, including Calcutta.

The city is yet to get a spell of heavy rain but the sky has been cloudy and conditions overcast for a couple of days now.

The usual date of the arrival of monsoon in Calcutta is June 8.

For the past few years, the arrival of monsoon has been timid in the city. But last year, a similar low-pressure area over Bay of Bengal had made the entry formidable, triggering 40-50mm of rain across the city. In Met parlance, more than 60mm of rain in 24 hours qualifies as heavy.

The system (current low-pressure area) will eventually enter land along the Odisha coast and travel towards Jharkhand. When it does, the western districts of Bengal are expected to get more rain, Met officials said.

“Calcutta is likely to continue having overcast conditions and light to moderate rainfall over the next three-four days,” said an official.