A few northern parts of the State may experience heavy rain this week, while moderate rain is likely to continue over coastal districts and a few interior places.
A cyclonic circulation over south Tamil Nadu and neighbouring areas, extending up to 0.9 km above mean sea level, would influence the scattered rainfall over the State. The Meteorological Department predicts fairly widespread rainfall that is expected to cover 51% to 75% of the weather stations in Tamil Nadu from September 24.
Officials of the Department said muggy weather during the day may be offset by thundershowers during the evening or night in places like Chennai. Besides the prevailing weather system, convective activity would trigger thunderstorms.
On Wednesday, heavy rain with thunderstorms may lash isolated places in districts including Vellore, Tiruvallur, Dharmapuri, Salem, Tiruvannamalai and Kallakurichi. Some coastal and interior districts may get light to moderate rain.
The delta districts may receive heavy rain in one or two places from Thursday. There would be an increase in rainfall from Friday, with light to moderate rain covering many places of the State and Puducherry.
Ten districts, including Cuddalore, Chengalpattu and Tiruvallur, may receive isolated heavy rain.
During the 24 hours ending 8.30 a.m. on Tuesday, Manampoondi in Villupuram district and Kalasapakkam in Tiruvannamalai district recorded heavy rainfall of 16 cm.
Respite from humidity
Chennai residents had a respite from a humid day, as sudden showers lashed some parts of the city on Tuesday afternoon. Rain gauges at MRC Nagar, Taramani, Villivakkam and Meenambakkam recorded light rain of less than 1 cm till 5.30 p.m. The same weather trend may continue till the weekend as rain may favour Chennai and neighbouring areas.
N. Puviarasan, director, Area Cyclone Warning Centre, Chennai, said the trough line would help the rain-bearing clouds move into interior districts and impact fairly widespread rain. The State has recorded an overall rainfall of 36 cm, which is 20% in excess of its seasonal share, since June 1.
“However, Kanniyakumari district has a 29% deficit in seasonal rainfall. The weak performance of the southwest monsoon in Kerala also affected rain over Kanniyakumari. However, the shortfall may be bridged as the monsoon is active,” he said.
