Chennai: Intense rain activity is likely to shift towards interior Tamil Nadu over the next few days, with coastal areas including Chennai expected to get occasional light spells. India Meteorological Department has forecast heavy rain at isolated places over the Western Ghats, moderate rain over southern Tamil Nadu and light rain over Chennai on Sunday. Moderate rain is possible over isolated parts of interior Tamil Nadu on Monday and Tuesday.V R Durai, director, Area Cyclone Warning Centre, IMD, said the rain activity is due to two weather disturbances — an upper-air cyclonic circulation over south coastal Andhra Pradesh between 5.8km and 7.6km above mean sea level and another over the Comorin area at 3.1km. A trough, an elongated region of relatively low pressure, lies between the two circulations.“This rain. There is a possibility for light to moderate intensity rain over Chennai from Monday,” he said.Durai said a circulation might develop off the Chennai coast around Oct 15, increasing the rain intensity, but would not necessarily mark the onset of the northeast monsoon. “A circulation over the Arabian Sea might favour the onset of northeast monsoon because the circulation might change the wind pattern to northeasterlies, which is required for the onset of the monsoon,” he said.On Sunday, Chennai and its suburbs may get light rain in some areas during the evening or night, with temperatures ranging from 35-36°C to 27-28°C.Chennai received little rain in the latest 24-hour period, with IMD reporting nil rainfall on Friday. Since June 1, Chennai has recorded around 38cm of rain, 15% below normal, while Tiruvallur received 32cm (32% below normal), Kancheepuram 29cm (38% below) and Chengalpet 18cm (54% below). Tamil Nadu recorded around 26cm, 20% below normal, during June-Sept.The northeast monsoon will be crucial for replenishing drinking-water reservoirs ahead of next summer. IMD has forecast normal rainfall for Chennai during Oct-Dec, while central and northern Tamil Nadu, including Tiruvallur, which houses the reservoirs, could receive below-normal rainfall. The monsoon is expected to set in between Oct 15 and 21.“The trough could bring some light spells over Chennai after two or three days. But it may not be anything significant. Southwest monsoon may withdraw completely between Oct 12 and 15 and we can expect northeast monsoon to set in after that,” said Mahesh Palawat, chief meteorologist, Skymet Weather.
