Isolated very heavy rainfall lashed Tamil Nadu during the 24 hours ending on Monday morning while it was heavy over Konkan, Goa, Marathwada, Rayalaseema and Kerala. India Meteorological Department (IMD) said the heaviest rain (in cm) was recorded at Kudithangi and Valparai-13; Namakkal (all Tamil Nadu); and Kankavli (Coastal Maharashtra)-11 each. Other centres include Neryamangalam (Kerala) -10; Mylaudy, Yethapur, Mohanur, Palacaode (all Tamil Nadu) and Osmanabad (Maharahstra)-9 each; Uravakonda (Andhra Pradesh)-8; and Kanjirapuzha (Kerala) 7.

The IMD has said a cyclonic circulation will form over the North Andaman Sea by tomorrow (Tuesday) and may intensify to become a low-pressure area over the subsequent three days (by Thursday). It threw broad hints that the ongoing heavy rain over Tamil Nadu and Kerala will get better organised during the next few days in the run-up to the expected arrival of the North-East monsoon (NEM) over the South Peninsula.

No consensus on track

The IMD is already on record indicating the formation of a depression as the ‘low’ develops traction at a location almost equidistant from the Tamil Nadu and Andhra Pradesh coasts. It has not yet confirmed the onward track or intensity for the system. There is no consensus either among global tracking models, with sea-surface temperatures warming up to 30 deg Celsius on Monday, comfortably past the threshold level for hosting and sustaining strong weather systems.

Numerical weather predictions suggest the Andhra Pradesh coast will be the likely area for landfall by October 25, after the preparatory low-pressure area toys with the North Tamil Nadu and Chennai coasts. The final track would depend also on the behaviour of any intervening western disturbance approaching from the opposite side, one of which is expected to hit the hills of North-West India (Western Himalayas) from Monday night. The US Climate Prediction Centre has maintained a watch for a system with strength not less than that of a depression in the Bay during October 19-25.

Extended IMD outlook

An extended outlook has predicted fairly widespread to widespread light to moderate rainfall with isolated heavy falls, thunderstorms and lightning over Tamil Nadu, Puducherry, Karaikal and Kerala until Friday; over South Interior Karnataka today (Monday) and Lakshadweep from Tuesday to Thursday. Isolated very heavy rainfall is likely over Tamil Nadu, Puducherry, Karaikal and Kerala on Thursday. Widespread light to moderate rainfall with isolated heavy falls is likely over the Andaman and Nicobar Islands until Friday. Scattered/ to fairly widespread light to moderate rainfall with isolated heavy falls is forecast over Madhya Maharashtra, Konkan and Goa today (Monday).