CHENNAI: A low-pressure area is set to form over the Southwest Bay of Bengal and the adjoining Tamil Nadu coast on Wednesday, while heavy to very heavy rainfall is expected to continue over Tamil Nadu, Puducherry, and Karaikal until October 26, with moderate rain, thunderstorms, and lightning predicted for some areas in Chennai on Thursday, according to the Regional Meteorological Centre (RMC).
Twin weather systems have formed over the Bay of Bengal, bringing widespread heavy rainfall across the state. A trough from the cyclonic circulation over the Southwest Bay of Bengal off the north Tamil Nadu coast now extends from the cyclonic circulation to north coastal Andhra Pradesh at 3.1 km above mean sea level.
Additionally, an upper-air cyclonic circulation that lay over the Gulf of Thailand and adjoining Thailand and Myanmar on Tuesday is expected to emerge into the north Andaman Sea by Wednesday morning. Under its influence, a new low-pressure area is likely to form over the Southeast Bay of Bengal around October 23, after which it will move northwestwards and intensify.
According to the India Meteorological Department, widespread rainfall is likely over Tamil Nadu, Puducherry, and Karaikal over the next couple of days, followed by isolated to scattered rainfall between October 23 and October 26.
Heavy to very heavy rain, accompanied by thunderstorms, lightning, and gusty winds reaching 40 to 50 kmph is likely to occur at isolated places over Thoothukudi, Tirunelveli, and Kanniyakumari districts on Wednesday. Heavy to very heavy rainfall will continue in Tenkasi, Virudhunagar, and Ramanathapuram districts on Thursday.
Under similar wind conditions, heavy rain with thunderstorms and lightning is expected at one or two places over the Nilgiris, Coimbatore, Erode, Tiruppur, Namakkal, Karur, Theni, Dindigul, Tenkasi, Madurai, Virudhunagar, Pudukkottai, Thanjavur, Tiruvarur, Nagapattinam, Mayiladuthurai, Sivagangai, and Ramanathapuram, as well as the Karaikal area.
In Chennai, the maximum temperature is expected to hover around 30 degrees Celsius, with the minimum temperature dipping to 25 degrees Celsius on Wednesday.