Kolkata: The city was lashed by a sharp downpour that lasted more than an hour on Saturday evening, slowing down traffic in various parts of Kolkata that is already witnessing a pre-puja rush.
The rain was triggered by multiple systems, including a low-pressure area over north Bay of Bengal and adjoining coasts of Bangladesh and Bengal, which has now turned less marked.
But a cyclonic circulation now lies over northern parts of Gangetic Bengal and its neighbourhood. An upper-air circulation over north Bangladesh and adjoining sub-Himalayan Bengal has merged with the cyclonic circulation.
That apart, an upper air circulation over west central Bay of Bengal now lies off Andhra coast, said a bulletin issued by the Regional Meteorological Centre. It added that a trough has now formed from northeast Uttar Pradesh. “The merging circulations triggered the spells on Saturday. Since the systems are now weakening, the spells will get fewer and lose intensity from Sunday. But the cloud cover will persist and occasional spells will continue over the next two days,” said RMC weather scientist HR Biswas.
On Saturday, KMC drainage data revealed the areas in parts of south Kolkata and EM Bypass received more rain than north and south-west. Chingrighata, Tangra, Ballygunge and Jodhpur Park received more rain than places in north Kolkata like Maniktala, Ultadanga and Behala in the south-west.
The drainage pumping station at Chingrighata clocked 23.5 mm rain between 5 pm and 7 pm, that at Tangra clocked 22.2 mm during this period, Ballygunge 23 mm and Jodhpur Park 20 mm. Though the quantum of rain was not enough to cause waterlogging, it drenched pandal-hoppers and threw traffic out of gear.
In contrast, the drainage pumping station at Maniktala recorded 13 mm during the two-hour evening period, Ultadanga 10 mm and Behala Flying Club a measly 2.6 mm.