CHENNAI: The conditions are favourable for the onset of the Northeast monsoon over the Southern Peninsula within the next two to three days, said the Regional Meteorological Centre (RMC), Chennai. According to the weather department, under the influence of a twin upper-air cyclonic circulation over the south Andaman Sea and its neighbourhood and the Gulf of Mannar and the adjoining south Tamil Nadu coast, light to moderate rainfall, accompanied by thunderstorms, lightning, and gusty winds reaching speeds of 40–50 kmph, is likely at isolated places on Tuesday (October 13) across Thanjavur, Tir...