A powerful thunderstorm swept across Kolkata on Thursday evening, sending gusty winds through neighbourhoods, disrupting traffic with blinding showers and extending the city’s unsettled monsoon conditions even as the seasonal withdrawal resumed over eastern India.
The storm struck on the usual date for the monsoon’s withdrawal from south Bengal. The India Meteorological Department’s Alipore observatory recorded only 2.6mm of rain until 8.30pm, but several other parts of the city received significantly more, according to a report by the Met office. The uneven rainfall led to intense showers in multiple areas and made road travel difficult.
Gusty winds sent flowerpots flying from balconies, while frequent lightning lit up the evening sky. The combination of strong winds, poor visibility and heavy localised rain affected traffic movement across the city, although the supplied report did not provide a citywide assessment of road closures or accidents.
The weather developed as the southwest monsoon’s withdrawal from eastern India remained incomplete. The withdrawal line, which normally moves from west to east, had reached parts of the heartland including Jharkhand before stagnating because of multiple weather systems. The Met office said the retreat resumed on Thursday.
In its report, the weather office said the southwest monsoon had further withdrawn from the remaining parts of Maharashtra and some parts of Goa, Karnataka, Telangana and Odisha, along with more areas of Jharkhand and Chhattisgarh. It added that conditions were becoming favourable for further withdrawal from parts of eastern India and the northern peninsula, as well as many parts of northeast India, over the following three to four days.
The delay in the withdrawal from south Bengal did not mean that the city would remain dry. An upper-air cyclonic circulation was located over northeast Bihar and adjoining areas, while a trough extended from the circulation towards Telangana across Jharkhand, Odisha and Chhattisgarh. According to Met officials, these systems were feeding moisture into south Bengal. The available heat then helped trigger thunderstorms over the region.
The episode highlights the operational difficulty of relying on seasonal calendar dates to anticipate city-level weather conditions. October 8 is regarded as the usual date for the monsoon’s withdrawal from south Bengal, but the actual transition is shaped by the movement and interaction of wider weather systems. For commuters, the immediate consequence was a sharp contrast between the relatively low rainfall recorded at Alipore and much heavier showers in other parts of Kolkata.
The Met office expected the rain to subside from Saturday. A Met official said there was no rain warning for the period from October 10 to October 13. Further withdrawal of the southwest monsoon from eastern India is expected to continue over the next three to four days, subject to the prevailing weather systems.
