According to the India Meteorological Department, the low-pressure area that formed over the South-West Bay of Bengal off the coast of Sri Lanka on Wednesday has persisted and is expected to become 'more marked' (intensify) by Friday (IMD).
The 'low-pressure area' is expected to move towards the coasts of Tamil Nadu and Puducherry until Saturday morning. After crossing the coast, it will move to the west-northwest across Tamil Nadu-Puducherry and then into Kerala on Saturday and Sunday, according to the IMD.
The system will graze the northern parts of Sri Lanka before entering Tamil Nadu and moving into Kerala, according to IMD's numerical model projections. It would then take a step out into the South-East Arabian Sea and strengthen. Importantly, it will leave a moisture trail back over the Bay of Bengal, triggering the formation of a stronger weather system by November 18.
The US National Centers for Environmental Prediction predicts heavy to very heavy rainfall for the entire Coastal Tamil Nadu and adjoining South Coastal Andhra Pradesh during the current week, which ends on November 18. (Friday next).
The heavier rains may spread to parts of North Coastal Tamil Nadu (around Chennai) and adjoining South Coastal Andhra Pradesh, Telangana, North Interior Karnataka, and parts of West Maharashtra in the coming week.
Meanwhile, according to the IMD, the current 'low' will bring fairly widespread to widespread rainfall with isolated heavy to very heavy rainfall over Tamil Nadu, Puducherry, Karaikal, Rayalaseemam, and South Coastal Andhra Pradesh for three days beginning Friday and isolated heavy rainfall over Kerala and Mahe from Friday to Monday. On Friday, isolated extremely heavy rainfall is expected over North Coastal Tamil Nadu (including Chennai), Puducherry, and Karaikal; and on Saturday, over North Tamil Nadu, Puducherry, and Karaikal.
Warning to Fishermen
During the next three days, the intensified 'low' will bring squally weather with wind speeds of 40-45 kmph gusting to 55 kmph (depression-strength) over the South-West and adjoining West-Central Bay (off the Tamil Nadu and Andhra Pradesh coasts); along and off the South Andhra Pradesh-Tamil Nadu-Puducherry and Sri Lanka coasts; the Gulf of Mannar and adjoining Comorin Fishermen are advised not to enter these areas during this time.
In an apparent reference to the formation of the second 'low,' an extended IMD forecast said fairly widespread light to moderate rainfall is likely over many parts of the South Peninsula and the Islands in the Bay and the Arabian Sea.
