Low pressure likely to transform into depression today, warns Met
Times of India | 29 May 2025
12 Kolkata: The low-pressure system that has formed over the Bay of Bengal is set to transform into a depression by Thursday morning and move towards the Bengal and Odisha coast, triggering heavy rain in the city and other parts of Bengal. The system, after its formation on Tuesday, started gaining strength and became a well-marked system, which is a step before it becomes a depression.With the system set to become a depression, the Met office has upgraded the rain alert for Kolkata to very heavy. In Met parlance, heavy to very heavy rain means an amount between 70 to 200 mm. In case heavy rain lashes the city, some areas, especially low-lying ones, are expected to get inundated. According to the prediction, the rain could be accompanied by squalls."The movement of the system is very insignificant at the moment. But it will become faster after the low-pressure area assumes the magnitude of a depression by Thursday morning. The window period for heavy rain is between Thursday afternoon and Friday," said meteorologist HR Biswas, head of the weather forecast section at the Regional Meteorological Centre, Kolkata. In Kolkata, the impact will be felt till Saturday, at least in the form of light spells.Along with Kolkata, the Met office has issued a heavy rain alert for districts like North 24 Parganas, South 24 Parganas, Howrah, Hooghly, and also at places in East Burdwan, East Midnapore, Nadia and Murshidabad.Meteorologists said that in a system like a low pressure, the centre is not well-defined and it covers a huge expanse. Once it becomes a depression, it is easier to pick up the centre and henceforth its distance from the city can be calculated more accurately.The Met officials said north Bengal will be impacted by the depression more than the southern districts. "Whenever a system like a low-pressure area forms over the Bay of Bengal, it can trigger rain up to 1,000 km away from the system, with the intensity higher in areas that are closer," said Biswas.According to a special IMD bulletin, the system at present is positioned over the Northwest Bay of Bengal off the Odisha coast. It is likely to move slowly northwards and concentrate into a depression over the north Bay of Bengal.The city has already started getting showers from clouds pushed up by the low pressure. The showers are keeping the mercury well below the normal mark. On Wednesday, the city recorded a maximum temperature of 31.4°C, 3.7 notches below the normal mark, while the minimum temperature at 25.1°C was 2.1 degrees below the normal.