Kolkata, July 18 (IANS) The Regional Meteorological Centre (RMC) at Alipore on Saturday issued a red alert for heavy rainfall in north Bengal till Monday and forecast an increase in rain activity across south Bengal, including Kolkata, from Tuesday onwards. According to the Met office, scattered rainfall will continue across south Bengal districts till Tuesday, after which moderate to heavy rain accompanied by thunderstorms is likely to intensify and persist till Friday.Heavy rainfall is expected in North 24 Parganas, South 24 Parganas and Nadia districts on Tuesday. Several other parts of south Bengal are also likely to experience rain and thundershowers, with gusty winds reaching speeds of 30-40 kmph.In north Bengal, Jalpaiguri and Alipurduar districts are likely to receive extremely heavy rainfall on Saturday and Sunday. The Met office has also warned of heavy to very heavy rain in Darjeeling, Kalimpong, Cooch Behar and other districts adjoining the Himalayan foothills till Monday. While rainfall activity may ease slightly from Tuesday, a heavy rain alert remains in force for Jalpaiguri and Kalimpong till Wednesday.

Meteorologists attributed the weather conditions to a well-marked low-pressure area over the northwest Bay of Bengal adjoining the Odisha-West Bengal coast, along with an associated cyclonic circulation extending up to 5.8 km above mean sea level. The monsoon trough currently stretches from Punjab through Haryana, Uttar Pradesh, Bihar and West Bengal to the north Bay of Bengal, drawing substantial moisture inland and enhancing rainfall activity over the region.The Met office also warned fishermen against venturing into the sea off the West Bengal coast till Saturday, citing strong winds of 35-45 kmph, gusting up to 55 kmph, under the influence of the weather system.Meanwhile, Kolkata recorded a minimum temperature of 27.7 degrees Celsius on Saturday, 0.8 degrees above normal, while Friday's maximum temperature settled at 31 degrees Celsius, 1.8 degrees below normal. 

/IANS