Update – December 12, 2016
The very severe cyclonic storm (VSCS)- VARDAH over westcentral and adjoining southwest Bay of Bengal moved further nearly westwards during past 6 AM with a speed of 13 kmph and lay centred at 5:30 AM of today, the December 12, 2016 over westcentral and adjoining southwest Bay of Bengal near Latitude 13.2ºN and Longitude 81.6ºE, about 150 km east-northeast of Chennai and 220 km eastsoutheast of Nellore.
The system is very likely to move nearly westwards and cross north Tamil Nadu and south Andhra Pradesh coasts, close to Chennai as a severe cyclonic storm with a wind speed of 100 to 110 kmph gusting to 120 kmph by today, December 12, 2016 afternoon.
Forecast track and intensity of the system are given in the table below: –
|Date / Time (IST)||Position
(lat. oN/ long. oE)
|Maximum Sustained Surface Wind Speed (kmph)||Category of Cyclonic Disturbance|
|December 12, 2016 / 05:30||13.2 / 81.6||120 – 130 Gusting to 140||Very Severe Cyclonic Storm|
|December 12, 2016 / 11:30||13.2 / 80.8||110 – 120 Gusting to 130||Severe Cyclonic Storm|
|December 12, 2016 / 17:30||13.3 / 80.1||100 – 110 Gusting to 120||Severe Cyclonic Storm|
|December 12, 2016 / 23:30||13.3 / 79.3||65 – 75 Gusting to 85||Cyclonic Storm|
|December 13, 2016 / 05:30||13.4 / 78.5||40 – 50 Gusting to 60||Depression|
The very severe cyclonic storm, VARDAH is being monitored by Doppler Weather Radar at Chennai apart from Satellite and other observations.
Warnings issued by IMD: –
- Heavy Rainfall Warning: Rainfall at most places with isolated heavy to very heavy falls over south coastal Andhra Pradesh, north coastal Tamil Nadu and Puducherry is very likely during the next 36 hours. The rainfall intensity will increase gradually becoming heavy to very heavy rainfall (7-19 cm) at a few places and isolated extremely heavy rainfall (≥ 20 cm) over Chennai, Thiruvallur and Kanchipuram districts of Tamil Nadu and Nellore and Prakasam districts of Andhra Pradesh on December 12.
- Wind warning: Squally winds speed reaching 50-60 kmph gusting to 70 kmph would prevail along and off Andhra Pradesh and adjoining north Tamil Nadu coasts becoming 100-110 kmph gusting to 120 kmph during the time of landfall along and off Chennai, Thiruvallur and Kanchipuram districts of Tamil Nadu and Nellore and Prakasam districts of Andhra Pradesh.
- Sea condition: Sea condition will be high to phenomenal along and off these coasts from December 12 morning.
- Storm surge: The tidal wave of about one meter height above the astronomical tide is very likely to inundate the low-lying areas of Chennai, Thiruvallur and Kanchipuram districts of Tamil Nadu and Nellore districts of Andhra Pradesh during the time of landfall.
- Damage Expected: Damage to thatched huts/houses. Roof tops may blow off. Unattached metal sheets may fly. Minor damage to power and communication lines. Breaking of branches and uprooting of trees. Major damage to Kutcha and damage to Pucca roads. Damage to paddy crops, banana, papaya trees and orchards, Flooding of escape routes over Chennai, Thiruvallur and Kanchipuram districts of Tamil Nadu; Ongole & Nellore districts of Andhra Pradesh and Puducherry.
- Action Suggested: Fishermen are advised not to venture into sea along and off south Andhra Pradesh, north Tamil Nadu and Puducherry coasts during next 24 hours. Coastal hutment dwellers are advised to move to safer places.
Post Landfall Outlook: –
- Even after landfall, the system is likely to maintain its cyclonic storm intensity for next 06 Hours and weaken gradually thereafter. Under its influence, rains at most places with heavy to very heavy falls at few places likely to continue in Chennai, Thiruvallur & Kanchipuram districts of north Tamil Nadu, Puducherry and Nellore & Prakasam districts of Andhra Pradesh during next 12 hrs after landfall. Winds speed reaching 65-75 kmph gusting to 85 kmph likely to continue over these districts during next 06 hrs after landfall and gradually decrease thereafter.
- As the cyclone moves inland north Interior districts of Tamil Nadu and Rayalaseema may also experience heavy to very heavy rain at isolated places during next 24 hours after land fall and squally winds reaching 40-50 kmph gusting to 60 kmph likely during next 12 hrs after the landfall.
- People are advised to remain in safe places and cooperate with state government officials and disaster management agencies.
__________________________________________________________________Tropical Storm ‘Vardah’, what we know so far
(December 9, 2016)
The cyclonic storm, Vardah over southeast Bay of Bengal remained practically stationary during past 3 AM and lay centred on December 9, 2016 over southeast Bay of Bengal near latitude 12.1ºn and longitude 90.4ºe, about 990 km southeast of Visakhapatnam, 1090 km east-southeast of Machilipatnam and 250 km west-northwest of Port Blair. the system is very likely to intensify further into a severe cyclonic storm during next 12 hours. it is very likely to move initially northwestwards, then west-northwestwards and cross Andhra Pradesh coast between Nellore and Kakinada around afternoon/evening of December 12, 2016.
However, there is possibility of slight weakening of the system before landfall.
Forecast track and intensity of the system are given in the table below: –
(lat. 0N/ long. 0E)
surface wind speed (kmph)
|Category of cyclonic
|09-12-2016/0300||12.1/90.4||80-90 gusting to 100||Cyclonic Storm|
|09-12-2016/0600||12.4/90.3||90-100 gusting to 110||Severe Cyclonic Storm|
|09-12-2016/1200||12.7/90.1||95-105 gusting to 115||Severe Cyclonic Storm|
|09-12-2016/1800||13.1/89.6||100-110 gusting to 120||Severe Cyclonic Storm|
|10-12-2016/0000||13.4/89.0||110-120 gusting to 130||Severe Cyclonic Storm|
|10-12-2016/1200||14.2/87.0||110-120 gusting to 130||Severe Cyclonic Storm|
|11-12-2016/0000||14.6/85.1||110-120 gusting to 130||Severe Cyclonic Storm|
|11-12-2016/1200||14.9/83.5||100-110 gusting to 120||Severe Cyclonic Storm|
|12-12-2016/0000||15.1/82.0||80-90 gusting to 100||Cyclonic Storm|
|12-12-2016/1200||15.4/80.4||65-75 gusting to 85||Cyclonic Storm|
|13-12-2016/0000||15.6/78.6||40-50 gusting to 60||Depression|
The Sea Surface Temperature (SST) is around 28-29˚c. The SST decreases towards northwest and westcentral Bay of Bengal becoming 26-270c near north Andhra Pradesh and Odisha coasts. The ocean heat content is about 70-80 kj/cm2 over the system and gradually decreases towards northwest, becoming less than 50 kj/cm2 near, Odisha and Andhra Pradesh coasts except over a small pocket of westcentral bay off central Andhra Pradesh coast where it is 60-70 kj/cm2. The low level convergence is about 20×10-5 second-1 to west-northwest of system centre, the upper level divergence is around 10×10-5 second-1 to west-northwest of the system centre and the low level relative vorticity has increased during past 12 hours and is about 250×10-6 second-1 to the south of the system centre. The vertical wind shear of horizontal wind is high (20-25 pknots) around the system centre and is same along the forecast track. The madden julian oscillation index lies in phase 2 with amplitude less than 1. It will move to phase 3 during next 3 days with increasing amplitude becoming > 1. Considering the environmental parameters, these are favourable for intensification of the system into a severe cyclonic storm during next 24 hours and its northwestward/west-northwestward movement towards Andhra Pradesh coast during next 3-4 days.
The latest total precipitable water imagery (tpw) indicates cold and dry air incursion over north and westcentral bay off Andhra Pradesh, Odisha coasts. In addition, high vertical wind shear and lower SST and ocean thermal energy near Andhra Pradesh coast will be unfavourable factors when the system reaches nearer to Andhra Pradesh coast. It may lead to weakening of the system to some extent before landfall.