Cyclone Nivar, (pronounced Nivaar, meaning atmosphere), is likely to cross the coasts of Tamil Nadu and Puducherry on Wednesday night as a “very severe cyclonic storm” with a wind speed of 120 to 130kmph gusting to 145 kmph.
Nivar has already intensified into a severe cyclonic storm over the southwest Bay of Bengal and moved west-northwestwards with a speed of 6kmph in the past six hours and lay centred over southwest Bay of Bengal about 300km east-southeast of Cuddalore, about 310km east southeast of Puducherry and 370km south southeast of Chennai. It is very likely to intensify further into a very severe cyclonic storm during the next 12 hours.
Nivar is then likely to move west-northwestwards for next 6 hours and northwestwards thereafter. It is very likely to cross Tamil Nadu and Puducherry coasts between Karaikal and Mamallapuram around Puducherry on Wednesday night as a very severe cyclonic storm, India Meteorological Department (IMD) said in its 6am bulletin.
Till Tuesday, IMD had said Nivar was likely to make landfall during the late evening hours but that has been upgraded to night in the Wednesday morning bulletin. Very heavy rainfall of 12 mm has been recorded in Chennai from 8.30 am on Tuesday to 5.30am of Wednesday.
Until Tuesday afternoon, the forecast was that Nivar would cross the Tamil Nadu coast as a severe cyclonic storm with a wind speed of 100 to 110kmph gusting to 120 kmph. But the cyclone intensified rapidly, according to independent scientists.
Widespread rain with thunderstorm activity is very likely over coastal and north interior Tamil Nadu, Puducherry and Karaikal during November 24 to 25, and over south coastal Andhra Pradesh, Rayalaseema during November 25 to 26, and southeast Telangana on November 26. Extremely heavy rainfall (over 20 cm) activity is likely over coastal and north interior Tamil Nadu and Puducherry (Pudukottai, Thanjavur, Tiruvarur, Karaikal, Nagapattinam, Cuddalore, Ariyalur and Perabalu districts during November 24 and Kadalur, Kallakurchi, Puducherry, Villupuram, Tiruvannamalai, Chengalpattu to Ariyalur, Perambalur and Karaikal districts during November 25) and over Nellore and Chittoor districts of Andhra Pradesh on November 25 and over Rayalseema and southeast Telangana on November 26.
IMD scientists said that it was not possible to confirm the exact time and location of landfall until Wednesday afternoon when models will have a clearer picture.
Gale wind speed reaching 75-85kmph gusting to 95kmph is prevailing over Southwest Bay of Bengal. It would further increase, becoming 110-120kmph gusting to 135kmph over the southwest Bay of Bengal from November 25 morning, increasing to 120-130kmph gusting to 145kmph during noon to night of November 25. Sea condition is high over Southwest Bay of Bengal and rough to very rough along and off Tamil Nadu, Puducherry, south Andhra Pradesh coasts and over Gulf of Mannar. It would gradually become very high (9 to 14 metres wave height) over the southwest Bay of Bengal from November 24 night and phenomenal (over 14 metres wave height) over the same area from noon to night of November 25.
Tidal waves of about 1-1.5m height above the astronomical tide are very likely to inundate the low-lying areas of north coastal districts of Tamil Nadu and Puducherry near the place of landfall according to the IMD bulletin. Total destruction of thatched houses, extensive damage to kutcha houses is likely, apart from bending or uprooting of communication lines, flooding of escape routes, disruption of railways, etc.
There is red category warning for extremely heavy rain in coastal and north interior Tamil Nadu, Puducherry and Karaikal on November 25 and for Rayalseema on November 26. “The cyclone has gradually intensified and wind speed has increased so the warnings have changed,” said K Sathi Devi, head, national weather forecasting centre on Tuesday evening.
“In November 2017, cyclone Okchi intensified very rapidly from a moderate cyclone to a very severe cyclone in 24 hours resulting in the death of 844 people in India and Sri Lanka. The environmental conditions are similar for cyclone Nivar, with warmer waters and winds favouring rapid intensification to a very severe cyclone in 24 hours…” wrote Roxy Mathew Koll, a climate scientist at Indian Institute of Tropical Meteorology in Pune on his social media post. “The area from where the cyclone is passing is 1 to 1.5 degrees Celsius warmer than normal as per National Oceanic and Atmospheric Administration’s real time data.”