An east west shear zone extending upto 4.5 km above mean sea level runs from southeast Arabian sea to southwest Bay of Bengal across South Interior Karnataka, north Kerala and north Tamilnadu. Yesterday’s cyclonic circulation over southeast Arabian Sea now lies over eastcentral & adjoining southeast Arabian Sea off Karnataka north Kerala coasts and extends upto mid tropospheric level. Under its influence, a Low Pressure Area is likely to form over Eastcentral Arabian Sea off south Maharashtra coasts during next 24 hours. It is likely to move westnorthwestwards and become more marked during the subsequent 48 hours. Yesterday’s cyclonic circulation over South Interior Karnataka & adjoining north Interior Tamilnadu has merged with the above cyclonic circulation over eastcentral & adjoining southeast Arabian Sea off Karnataka north Kerala coasts. A trough runs from the above cyclonic circulation over eastcentral & adjoining southeast Arabian Sea off Karnataka north Kerala coasts to north Konkan across south MaharashtraGoa coasts at 0.9 km above mean sea level.
WEATHER FORECAST FOR TAMILNADU AND PUDUCHERRY
Thunderstorm with light to moderate rain is likely to occur at many places over Tamilnadu, Puducherry & Karaikal area.
Thunderstorm with heavy rain is likely to occur at isolated places over Erode, Nilgiris, Coimbatore, Theni, Dindigul, Tiruppur, Salem, Dharmapuri, Namakkal and Kallakurichi districts of Tamilnadu.
Next two days: Thunderstorm with light to moderate rain is likely to occur at many places over Tamilnadu. Thunderstorm with heavy to very heavy rain is likely to occur at isolated places over Tiruvallur, Chennai, Kancheepuram, Chengalpattu, Ranipet, Vellore, Villupuram, Tiruvannamalai, Kallakurichi, Cuddalore, Mayiladuthurai and delta districts of Tamilnadu, Puducherry and Karaikal area.
HEAVY RAINFALL WARNING
Today (16.11.2021): Heavy rain is also likely to occur at isolated places over Erode, Nilgiris, Coimbatore, Theni, Dindigul, Tiruppur, Salem, Dharmapuri, Namakkal and Kallakurichi districts of Tamilnadu
Next two days: Heavy to very heavy rain is likely to occur at isolated places over Tiruvallur, Chennai, Kancheepuram, Chengalpattu, Ranipet, Vellore, Villupuram, Tiruvannamalai, Kallakurichi, Cuddalore, Mayiladuthurai and delta districts of Tamilnadu, Puducherry and Karaikal area.
Reference: http://imdchennai.gov.in/tn_fc.pdf
http://www.imdchennai.gov.in/hrw_district.htm