Chennai, Nov 25 : Severe cyclonic storm Nivar is expected to cross Tamil Nadu and Puducherry coasts around midnight or early hours of Thursday as a very severe cyclonic storm, India Meteorological Department said on Wednesday. Moving at a speed of about 7kmph over the past six hours, the severe cyclonic storm Nivar lay centred about 290km east-southeast of Cuddalore, about 300km east-southeast of Puducherry and 350km south-southeast of Chennai, the weather department said. Over the next 12 hours, Nivar is likely to intensify into a very severe cyclonic storm. Nivar is likely to move northwestwards and cross Tamil Nadu and Puducherry coasts between Mamallapuram and Karaikal around Puducherry during the intervening night of November 25 and 26 as a very severe cyclonic storm. The wind speed when Nivar crosses the coast will be 120-130 kmph gusting to 145 kmph. The weather department has forecast fairly widespread to widespread rainfall/thunderstorm activity very likely over coastal and north interior Tamil Nadu, Puducherry and Karaikal, south coastal Andhra Pradesh and Rayalaseema during November 25 and 26 and southeast Telangana on Thursday. Isolated extremely heavy rainfall activity also very likely over coastal and north interior Tamil Nadu and Puducherry (Thanjavur, Tiruvarur, Nagapattinam, Cuddalore, Chennai, Kanchipuram, Chengalpattu, Myladuthirai, Ariyalur, Perambalur, Kallakurchi, Villupuram, Tiruvannamalai, Puducherry and Karaikal districts); over Nellore and Chittoor districts of Andhra Pradesh on Wednesday and over Rayalseema and southeast Telangana on Thursday. /IANS