True to the predictions by India Meteorological Department (IMD), a low-pressure area has formed over North Andaman Sea, adjoining South Andaman Sea and South-East Bay of Bengal on Thursday morning as the previous day’s parent cyclonic circulation gained traction and intensified in the first of a series of expected rounds.

Cyclone over sea by Monday

IMD said, on Thursday morning, that the system may recurve to the North and intensify into a cyclone over West-Central and adjoining East-Central Bay, away from Tamil Nadu and Andhra Pradesh coasts by Monday. Subsequently, it may shift track to North-North-East and reach near West Bengal-Bangladesh coasts by Tuesday next (October 25), skirting even the Odisha coast. It remains to be seen if the North-East monsoon uses this window for an onset over the South Peninsula.

Trough towards TN coast

The IMD also took note of a trough running from the ‘low’ over the North Andaman Sea and adjoining South Andaman Sea and the South-East Bay towards the Tamil Nadu coast, providing an atmospheric highway for clouds and moisture to stream in. The coast would likely be in the line of sight of the system at least until Monday, after which it might recurve to the North leading to a shift in direction of winds. They would start blowing in from the land instead of the sea and drive away the moisture and clouds trailing the system propelling towards West Bengal-Bangladesh.

Western disturbance waiting

A western disturbance is waiting to enter across the international border located along a line linking Multan and Bahawalnagar in East Pakistan with Bathinda in Punjab, India, which would be instrumental in shifting the storm away from Tamil Nadu, Andhra Pradesh, and Odisha. Opposing winds from the western disturbance are forecast to scoop up the system from off the Andhra Pradesh coast by Tuesday and dump it over West Bengal-Bangladesh coasts.

Better consensus on track

On Thursday, the Canadian Meteorological Centre was the lone model to suggest a cyclone track towards Myanmar, while a peer group comprising the European Centre for Medium-Range Weather Forecasts, the US National Centres for Environmental Prediction-Global Forecasts System, the Japanese Meteorological Agency, the US Navy Global Environmental Model, and the UK Met Office pointed towards North Odisha-West Bengal-Bangladesh coasts.

Rain for TN, Puducherry, Kerala

IMD’s rainfall projections more or less align with the projected track of the system. Fairly widespread to widespread light to moderate rainfall with isolated heavy falls, thunderstorms, and lightning has been forecast for Tamil Nadu, Puducherry, Karaikal, Kerala, and Mahe until Saturday and over South Interior Karnataka and Lakshadweep today (Thursday). Fairly widespread to widespread light to moderate rainfall with isolated heavy falls, thunderstorms and lightning is likely also over Odisha on Sunday and Monday and over the plains of West Bengal and Tripura on Monday.

Isolated very heavy rainfall is likely over Coastal Odisha on Monday while it would be widespread light to moderate with isolated heavy falls over Andaman and Nicobar Islands until Saturday. Isolated light rainfall and snowfall have been forecast for the hills of North-West India (Western Himalayas) during this period as the western disturbance chugs in from across the international border.