The 24 hours ending Thursday morning saw isolated very heavy rainfall over Rayalaseema, Assam, Meghalaya, North Interior Karnataka and the hills of West Bengal as Sikkim while it was heavy over Tamil Nadu, Chhattisgarh, South Interior Karnataka, Telangana, plains of West Bengal, Konkan, Goa, Himachal Pradesh, Jharkhand and Odisha.
Withdrawal to gather pace
India Meteorological Department (IMD) said the withdrawal of the South-West monsoon from North-West India and adjoining Central India will gather pace over the next 2-3 days. It is likely to exit from the remaining parts of Gujarat, some parts of Maharashtra and some parts of East India during subsequent two days (early next week). This will set the ground for successor North-East monsoon to make an onset over the South Peninsula.
Bay system behaviour
Wednesday’s cyclonic circulation persisted while a peer system over the North Andaman Sea now lies over the Central Bay, half way on its track towards the East Coast. Contrary to earlier outlook, it appears it might make a quiet landfall over the Chennai coast in the next two days, leaving the ground clear for another circulation emerging from the South China Sea to push in and hurtle towards the Chennai coast by October 20. It could likely bring in the North-East monsoon, according to early predictions from the numerical models of the IMD.
Chances for a depression
The US Climate Prediction Centre has put the Bay of Bengal under watch for a weather system of the strength of at least a depression during the week from October 19 to 25 (40 per cent chance) while some other models suspect a full-fledged cyclone is in the making. A similar alert is valid for the South China Sea to the immediate East of the Bay, perhaps hinting at tele-connection between the brewing systems on either side of Indochina. Both the Bay and the Arabian Sea basins have been notified as areas of interest in terms of enhanced possibility of hosting weather systems during the week.
Widespread rain forecast
Back hoe on Thursday, cyclonic circulation lay over the East-Central Arabian Sea off the Konkan-Goa coast. Along with cyclonic circulations over the Comorin and the Central Bay, this is expected to trigger fairly widespread to widespread light to moderate rainfall with isolated heavy falls, thunderstorms and lightning over Tamil Nadu, Puducherry, Karaikal, Kerala and Mahe until Monday; over South Interior Karnataka on Friday to Saturday and on Monday; over Coastal Andhra Pradesh on Friday and Coastal Karnataka on Monday. Fairly widespread to widespread light to moderate rainfall with isolated heavy falls is likely over the Andaman and Nicobar Islands from Saturday to Monday.