Chennai: A drama could unfold over the Bay of Bengal as brewing cyclone Arnab threatens to pull the low-pressure area hovering over the Arabian Sea into its circulation, potentially bringing more rain to Chennai and neighbouring districts. Weathermen said the interaction could trigger heavier spells from Sunday night to Monday morning, before the city enters a likely break in rainfall.The IMD has issued a red alert on Sunday for heavy to very heavy rainfall of 12-20cm in 24 hours for three districts along the Western Ghats, an orange alert for heavy to very heavy rainfall for 14 districts and a yellow alert for heavy rain of 6-12cm in 24 hours for 17 districts, including Chennai, Chengalpet, Kancheepuram and Tiruvallur. On Monday, heavy to very heavy rainfall may be restricted to southern and western districts.V R Durai, director of the Area Cyclone Warning Centre at RMC Chennai, said the system over the east-central Bay of Bengal would draw the Arabian Sea low-pressure area, potentially bringing heavy rain to Chennai and neighbouring districts on Sunday. A trough extending from the cyclonic circulation associated with the Arabian Sea system towards north coastal Tamil Nadu could further enhance rainfall.“The trough will continue to bring rainfall till Oct 26, as it may weaken gradually. After that, dry weather may prevail for a few days,” he said.From Oct 27 to around Nov 3, moisture is likely to be concentrated around the cyclone as it moves towards the south Andhra Pradesh-north Odisha coast, with landfall expected before it moves northwards towards Gangetic West Bengal. Dry weather may prevail over Chennai during this period, leading to a slight rise in daytime temperatures.“The temperature may not be that high as it is not the season for that because the Sun has moved south of the equator,” Durai said.On Sunday, Chennai and its suburbs may receive moderate to heavy rain, with thunderstorms and lightning in some areas. Partly cloudy skies are expected, with maximum temperatures of 31-32°C and minimum temperatures of 25-26°C.Blogger Pradeep John said the heavier spells could occur from Sunday night to Monday morning. “Then we go into a break in rains,” he said in a series of online posts.Since Oct 1, Chennai has recorded 278.8mm of rain, around 69% above normal. Kancheepuram has received 163.8mm, around 28% above normal; Chengalpet, 145.2mm, around 4% below normal; and Tiruvallur, 198.9mm, around 48% above normal.
