BB-17 has been upgraded to Cyclone "Nada" status by IMD and International Weather Models.
As per IMD Bulletin .." The cyclonic storm “Nada” over southwest Bay of Bengal moved northwestwards during past six hours with a speed of about 27 kmph and lay centred at 1730 hrs IST of today, the 30th November, 2016 near Latitude 9.8ºN and Longitude 84.0ºE over southwest Bay of Bengal, about 550 km southeast of Chennai,"
Moving along the Southern Edge of the Sub Tropical Ridge, this "Cyclone" will track towards the Tamil Nadu coast.
Please not I have put "Cyclone" into inverted commas.Estimated central Pressure is 1000 mb and estimated core winds at 40 knts,
Heavy showers expected in Chennai from 1st December, amounting to around 50 mms. Rains will decrease to half the amount on 2nd and substantially decrease thereafter.