Kolkata is likely to receive heavy rain on Thursday as a deep depression over the Bay of Bengal crosses the Andhra Pradesh–south Odisha coast and moves west-northwestwards into central India, according to a Met bulletin issued on Wednesday evening.
The system was located about 30km south-southwest of Kalingapatnam in Andhra Pradesh, 90km east-northeast of Visakhapatnam and 160km southwest of Gopalpur in Odisha around 7.45pm. The bulletin said it was very likely to cross the north Andhra Pradesh and adjoining south Odisha coast between Visakhapatnam and Gopalpur within the next three to four hours.
Kolkata had already experienced rain since Wednesday morning. The Alipore Met office recorded around 28mm of rainfall up to 8.30pm, while the city remained largely cloudy and overcast apart from a brief clearer period during the forenoon. The weather brought down the maximum temperature to 29.6 degrees Celsius, three notches below normal. The temperature is expected to remain below 30 degrees on Thursday.
The forecast indicates that the intensity and spread of rain will increase across south Bengal on Thursday. Very heavy rain is likely in East Midnapore, West Midnapore and Jhargram, while heavy rain is expected in South 24-Parganas, Bankura, Purulia, West Burdwan, Birbhum, Howrah and Kolkata.
Heavy rain is also forecast in Bankura, Purulia, West Burdwan and Birbhum on Friday. The intensity of rainfall across south Bengal is expected to decrease from Saturday. In north Bengal, Darjeeling, Jalpaiguri and Alipurduar are likely to receive heavy to very heavy rain on Thursday and Friday.
The Met bulletin warned that moderate to strong gusts could accompany the rain across the state. Squally winds reaching 45–55kmph, with gusts up to 65kmph, are likely along and off the Bengal coast until September 25. Very rough sea conditions are expected over the westcentral and northwest Bay of Bengal until the evening of September 24, with conditions likely to improve gradually thereafter.
Fishermen have been advised not to venture into the deep sea until September 25. The warning covers a system that began as a cyclonic circulation over Thailand on September 19 before emerging over the north Andaman Sea a day later. It subsequently developed into a low-pressure area, a well-marked low, a depression and then a deep depression.
Met officials said strong wind shear associated with active monsoon currents over the sea was preventing further sustained intensification of the system. The system is expected to continue moving west-northwestwards after crossing the coast, while rainfall and wind conditions remain under observation through Friday.
