Chennai, Nov 6 (IANS): The Regional Meteorological Centre (RMC) has issued a heavy rainfall warning and a yellow alert for 11 coastal districts of Tamil Nadu including Chennai during the next 24 hours.

Heavy rains will lash Chennai, Kancheepuram, Chengalpattu, Villupuram, Cuddalore, Myladuthurai, Nagapattinam, Thanjavur, Pudukottai, Thiruvarur and Ramanathapuram on Thursday while yellow alert has been issued in all these districts.

The rains will be due to the cyclonic circulation over the South Bay of Bengal.

The weather department also said that the system prevailing over the sea will lead to heavy rains over the next few days. A cyclonic circulation lies over central parts of Bay of Bengal in lower tropospheric levels which will lead to heavy rains in Chennai and adjoining districts.

Heavy to very heavy rains are predicted from November 8-12 in Theni, Dindigul, Madurai, Virudhunagar, Tenkasi, Tirunelveli, Kanyakumari, Thoothukudi, Ramanathapuram, Sivagangai, Pudukottai, Thanjavur, Thiruvarur, Nagapattinam and Myladuthurai districts of Tamil Nadu.

The weather department has also said that north and south Tamil Nadu will witness moderate to heavy rains in the next few days.

The Regional Meteorological Centre (RMC) has advised fishermen not to venture into the sea till November 9 as squally winds with wind speeds reaching 35kmph to 45 kmph and gusting to 55kmph over western parts of west-central and adjoining southwest Bay of Bengal along and off south Andhra Pradesh Coast and adjoins south Tamil Nadu coast.

The weather department also asked the fishermen who were in the deep sea to immediately return to the coast.

The Regional Meteorological Centre (RMC) in its seasonal data during the northeast monsoon (from October 1 to November 6) stated that Tamil Nadu received 247mm of rainfall of 219 mm which is 13 per cent excess. The highest amount of rainfall was recorded in the Coimbatore district with 410 mm is 102 per cent excess rainfall during the season.

Following the heavy rains for the last few days water level in Vaigai Dam is increasing and experts are monitoring the rising water levels. This is following the intense showers in the catchment areas of the river leading to an increased flow of water from Mullaperiyar to Vaigai dam.

Since the last three days there has been a steady flow of water to the Vaigai dam and the water level in the dam has increased to 64.34 feet. It may be noted that the total capacity of the dam is 71 feet.

Tamil Nadu Water Resources Department officials told IANS that the first flood warning would be issued when the water level rises to 66 feet, the second warning will be issued when the water level touches 68.5 feet and the third warning will be issued when the water level touches 69 feet.

With this, the water will be released from the Vaigai dam for irrigation purposes to the Madurai district.

The Vaigai dam, it may be noted, is the main water resource for districts like Theni, Dindigul, Madurai, Sivaganga and Ramanathapuram.

The rising water level in Vaigai has brought cheer to the farmers of these districts.