The India Met Department has extended its watch for a depression in the South-West Bay of Bengal by another day as convection (process of cloud-building) around a preparatory system failed to measure up to mark.
Earlier, it had expected the existing well-marked low-pressure area to become a depression by Monday and further into a deep depression by Tuesday.
On Monday, the Met said that the well-marked ‘low’ has moved slightly north from the previous day’s coordinates to settle over Sri Lanka, adjoining Gulf of Mannar and South-West Bay of Bengal.
It may not cross the Pamban-Nagapattinam stretch, but instead may move north-northwest-ward over the waters towards the North Tamil Nadu coast (around Chennai).
During this phase, the Met expects it to deepen into a depression. This will bring heavy to very rain to many parts of Tamil Nadu and Kerala.
Same track The European Centre for Medium-Range Weather Forecasts too predicts the same track for the system. It says the system would intensify a round off the Chennai-South Coastal Andhra Pradesh coast by Thursday.
Another round of intensification is likely off the coast of South Coastal Andhra Pradesh-Odisha following which the system may move steer itself slightly away from the coast.
The European Centre takes the storm towards the Myanmar coast for landfall by May 23. Weakening of the system in this manner will also cause the monsoon flows to wane across the Arabian Sea.
There is some revival in the flows indicated from May 26, but these would be routed via Sri Lanka into the Bay of Bengal and across Indo-China.
A counter-view is provided by the US National Centres for Environmental Prediction which says the system may cross the Puducherry coast and moving into interior Tamil Nadu where it would weaken.
Andaman onset Meanwhile, the Met has retained its prediction for the monsoon to break over Nicobar Islands, South Andaman Sea and adjoining South Bay of Bengal by tomorrow.
Overnight rain in many parts of South Tamil Nadu and Kerala on Monday morning affected the voting trends as both the states went for polls.
The rains are expected to pick up vigour over the next couple of days as the well-marked ‘low’ matures in the neighbouring seas.
Heavy to very heavy rains have been forecast for parts of Tamil Nadu and Kerala in the process; squally winds are likely off and along the coast of Tamil Nadu.
Fishermen have been advised not to venture out into the seas until Thursday, the Met outlook said.