The low-pressure area over South-East Bay of Bengal and adjoining South Andaman Sea has become well-marked, and is expected to intensify into a depression by Thursday, India Meteorological Department (IMD) has said. It would gather further steam and morph into a cyclone by Saturday, signalling the first time so far this North-East monsoon season when a weather system of such strength would have ventured closest to the Tamil Nadu coast. 

Gale winds off TN coast

According to the IMD, the South-West Bay that straddles the Tamil Nadu and adjoining Andhra Pradesh coast could bristle with squally winds with speeds reaching 40-50 km/hr gusting to 60 km/hr by Friday before ramping up to the projected peak as gale winds reaching of 60-70 km/hr gusting to 80 km/hr by Saturday. Fishermen out at sea from the Tamil Nadu to Odisha coast have been advised to return to coast as early as by tomorrow (Thursday). 

Cyclone landfall area

This wide swathe is being initially warned of disruptive weather due to the divergence in model outlook on where exactly the projected cyclone would choose to make a landfall. While the short-to-medium outlook from the IMD favours Coastal Andhra Pradesh to the North of Chennai as a likely location, western disturbances moving in from the opposite direction could have a bearing on where the system could ultimately cross land. 

Rain, thunderstorms warned

On Wednesday, a trough in easterlies ran up from North Kerala to North Madhya Maharashtra, which will interact with remnant westerlies from a previous strong western disturbance for next three days. This is even as the next in the series of disturbances, though not as strong, was located on Wednesday away to the West-North-West over Central Iran, and is expected to move across Afghanistan and Pakistan. Interaction of the easterlies and westerlies is expected to trigger the following:

Scattered to fairly widespread light to moderate rain/snow, thunderstorms and lightning over Jammu- Kashmir-Ladakh and Himachal Pradesh on Wednesday and Thursday. Heavy rain/snow is likely at isolated places also over Kashmir-Gilgit-Baltistan-Muzaffarabad on Thursday and light rain over the plains of North-West India until Saturday. 

Rough weather over TN

Light to moderate scattered to fairly widespread rain, thunderstorms and over Madhya Pradesh and Vidarbha until Saturday. Hailstorms at isolated places over Madhya Pradesh on Thursday. Light rain and thunderstorms over Madhya Maharashtra and Marathwada on Wednesday and Thursday. Hailstorms over Madhya Maharashtra and Marathwada on Thursday. 

In the South, light to moderate scattered to fairly widespread rain with thunderstorms over Rayalaseema, Tamil Nadu, Puducherry, Karaikal, Kerala and Mahe during next five days. Heavy rain likely over Rayalaseema on Wednesday; over Tamil Nadu, Puducherry and Karaikal until Sunday even as the projected cyclone lies closest to the coast; over Kerala and Mahe on Thursday and Saturday; and over Andhra Pradesh and Yanam on Saturday and Sunday.