The depression over the South-West Bay of Bengal is apparently leaving the Sri Lankan territory with a bearing at 520 km East-North-East of Jaffna on Monday morning, and moving closer to the Indian coast located at 490 km East-North-East of Karaikal; 580 km South-East of Machilipatnam in Andhra Pradesh; and 450 km East-South-East of Chennai, India Meteorological Department said.

The depression is likely to move further to North-West and maintain its intensity for today, the IMD said, adding it may shift track to West-North-West and move towards the South Andhra Pradesh-North Tamil Nadu-Puducherry coasts, and weaken gradually into a well-marked low-pressure area by tomorrow (Tuesday) morning as it encounters unfavourable conditions near the coast.

Flatters to deceive

The depression flattered to deceive the North Tamil Nadu coast after reserving the heaviest rain to the seas until morning, Chennai weather bloggers said.

Satellite pictures too showed a bulk of the thunderstorms waiting outside Chennai as well as Nellore and Kakinada in Andhra Pradesh, while clouds have been sheared off away to Srikakulam to the North and even Brahmapur in Odisha.

Clouds have been displaced after a western disturbance advanced into Uttarakhand and pushed the seasonal anticyclone with opposing north-westerly winds into Peninsular India.

Entrainment of dry air from land will compromise the vitals of the depression weakening it, as it homes in on Chennai by Thursday, according to IMD’s numerical guidance.

Fresh system, but only just

By this time, another circulation will have been initiated over the South-East Bay of Bengal. Isolated to scattered activity is predicted for the South Peninsula from Saturday to Monday while it will be scattered to fairly widespread over the Andaman & Nicobar Islands as this circulation moves in.

It is forecast to wither away mid-seas and weaken as a basin-wide trough. Still, numerical models indicate a strengthening of the easterly winds over the South Bay of Bengal from November-end.

Light to moderate rainfall at most places with isolated heavy to very heavy rainfall is likely over South Coastal Andhra Pradesh on Monday.

Light to moderate rainfall is likely in many places with isolated heavy rainfall over North Tamil Nadu, Puducherry, North Coastal Andhra Pradesh and Rayalaseema. Light to moderate rainfall is likely over North Coastal Andhra Pradesh on the same day.

Fishermen warning

On Wednesday, a similar weather pattern will pan out over North Tamil Nadu, Puducherry, South Coastal Andhra Pradesh and Rayalaseema.

Fishermen are advised not to venture into the South-West and adjoining West-Central Bay, the Gulf of Mannar and along and off the Andhra Pradesh, Tamil Nadu, Puducherry and Sri Lanka coasts till tomorrow and the Gulf of Mannar both today and tomorrow.