Districts along the Western Ghats and the adjoining interior districts would have to brace for a downpour for three days. The Meteorological Department has declared a red alert for a few districts along the Western Ghats as they may receive isolated extremely heavy rains on August 3 and 4.
The southwest monsoon that has turned vigorous over Kerala would bring more rains in the Western Ghats region and districts adjoining them. A combination of weather factors, including strong westerlies winds and cyclonic circulation over coastal Tamil Nadu and its neighbours, would trigger widespread rainfall.
Fairly widespread rainfall has been predicted at most places in the State this week. On Wednesday, a red alert has been sounded in districts, including Theni, Dindigul, Tiruppur and Coimbatore, as one or two places are likely to receive intense rain of above 21 cm. A total of nine districts, including Tirunelveli and Kanniyakumari, are expected to receive isolated heavy to very heavy rain of an intensity of up to 20 cm, and seven more districts are likely to get heavy rain.
According to the Indian Meteorological Department (IMD) bulletin, the downpour may have an impact on crops and cattle, flood low level areas and lead to landslides in hilly regions.
The IMD has issued a red alert for the Nilgiris and Coimbatore districts on Thursday as isolated extremely heavy rain is possible. Nearly 16 districts have chances of receiving heavy to very heavy spells of rain in a few places.
Officials said the heavy rain spell may last till August 5 in various districts. On Tuesday, heavy rain lashed several weather stations, and Chinnakalar and Valparai in Coimbatore district received 13 cm each, the highest quantity of rainfall recorded in the State for the day. Several places like Kodaikanal, Valparai, Hosur, Aruppukottai and Gobichettypalayam received light rain till 7.30 p.m. on Tuesday.
S. Balachandran, Deputy Director General of Meteorology, Chennai, said such widespread rain occurred due to intra-seasonal variability, when the shear zone over the Tamil Nadu region moves towards the north. This kind of weather pattern occurred on a timescale of once in 40 days. Moisture convergence and wind speed were other driving forces for such rainfall.
Though the department had earlier predicted heavy rain for Chennai and neighbouring districts, it has now been reduced to light to moderate intensity till Thursday as the weather system has shifted position.
Excess rainfall
The State has recorded an overall of 24.2 cm of rainfall this year’s southwest monsoon, which is nearly 94% more than its average of 12.5 cm for the season since June 1. Mr. Balachandran said, “This is the third consecutive year that the State was experiencing surplus rainfall. We expect this year too to end on a surplus note.”
He also noted that the repair of the S-band doppler weather radar on Rajaji Salai would begin on Wednesday. A slew ring bearing would be replaced in the radar.
