Cyclone 'Nilam' today intensified into a severe storm with extremely heavy rainfall expected over North coastal Tamil Nadu and Puducherry even as the weather department warned of extensive damage to huts, standing crops and power lines.
The cyclone is expected to cross between Puducherry and Nellore in Andhra Pradesh close to Chennai this evening.
"The system would intensify further into a severe cyclonic storm and move north-westwards and cross north Tamil Nadu and adjoining south Andhra Pradesh coast between Puducherry and Nellore close to Chennai by this evening, it said in its latest bulletin.
Gusty winds with a maximum surface wind speed of 45 kmph to 110 kmph is expected, it said.
Extremely heavy rainfall of over 25 cm or more is expected over north Coastal Tamil Nadu and Puducherry in the next 24 hours.
Rainfall at most places with isolated heavy to very heavy falls would occur over south coastal Andhra Pradesh, Rayalaseema and north interior Tamil Nadu in the next 48 hours with gale speeds of 90-100 kmph, gusting to 110 kmph along and off north Tamil Nadu, Puducherry and adjoining south Andhra Pradesh coasts.
The sea condition would be "high to very high" along and off North Tamil Nadu, Puducherry and South Andhra Pradesh coast, the Met office said.
Storm surge of about 1-1.5 metre over the astronomical tide is likely to inundate low lying areas of Chennai, Kancheepuram, Tiruvallur and Nellore districts, it said.
The Met office also advised total suspension of fishing operations and for coastal dwellers to move to safer places.
Danger signals ranging from seven to five have been hoisted at Chennai, Ennore, Cuddalore, Nagapattinam, and Puducherry ports.
Local cautionary signal number three has been hoisted at Pamban and Thoothukudi ports, it said.