Global weather tracking the deep depression over the south-west Bay of Bengal off Sri Lanka coast tend to agree the system is struggling to consolidate and intensify as projected Fengal cyclone as it runs into increased wind shear in the upper levels, which is damaging the storm tower.
The India Meteorological Department (IMD) too had earlier in the morning made a qualified update saying there is ‘a possibility of marginal intensification’ of the system into a cyclone with wind speeds of 65-75 km/hr gusting to 85 km/hr from this (Thursday) evening to tomorrow morning.
At 8.30 am this morning, the deep depression was practically stationary through preceding six hours as it lay anchored about 110 km east-northeast of Trincomalee in Sri Lanka; 310 km south-east of Nagapattinam; 410 km south-east of Puducherry; and 480 km south-southeast of Chennai. How long it can withstand vertical shear from winds blowing from the opposite direction needs watching as it ventures to move past Sri Lanka.
It will continue to move north-northwest and cross north Tamil Nadu-Puducherry coasts between Karaikal and Mahabalipuram around Saturday morning as a deep depression with wind speeds of 50-60 km/hr gusting to 70 km/hr. The longer it stays close to coast while slowing down, higher the prospects of rain for Tamil Nadu coast.
Going forward into early December (next week), it will be interesting to track of an incoming low-pressure area/depression from the South China Sea into south-east Bay of Bengal, and a likely easterly wave projected in its wake to propel towards the Sri Lanka and South Tamil Nadu coast.