The North-East monsoon is now being anchored by a low-pressure area over Lakshadweep in South-East Arabian Sea as a counterpart ‘low’ in the Bay of Bengal crumbled on Thursday.
The Arabian Sea system will pull in the moisture flows across Tamil Nadu and Kerala and bring rainfall in both states during the weekend and early into next.
The forecast for the next four days is as follows:
Friday: Heavy rain at isolated places over Lakshadweep.
Saturday: Heavy rain at isolated places over Tamil Nadu and Puducherry.
Sunday: Heavy rain at isolated places over Tamil Nadu and Puducherry.
Monday: Heavy rain at isolated places over Tamil Nadu, Puducherry and Kerala.
Extended outlook An extended outlook for the next 20 days (ending December 9) by the Indian Institute of Tropical Meteorology sees mostly ‘normal’ rainfall for southern parts of the peninsula.
A five-day phase from Tuesday next (November 23) may see the rains extend temporarily to southern parts of interior Maharashtra, thanks to the Arabian Sea ‘low.’
It will also push seasonally excess rain along the West Coast from Thiruvananthapuram through Coastal Karnataka, and even Goa-Konkan.
Meanwhile, satellite pictures this (Thursday) evening showed a bank of convective (rain-generating) clouds leaving Banda Aceh (Sumatra)-Andaman Sea in a direction towards the Tamil Nadu coast.
Winds fanning in from the Bay of Bengal into the ‘low’ in Arabian Sea will guide the formation towards its presumed target.
New system The Sumatran tip and the adjoining Andaman Sea is already expected to host what is likely the next low-pressure area and being put on a path across the Bay towards the Tamil Nadu coast.
The Met projections for November 26 clearly show a system forming in the area. It tends to support a view maintained by the US Climate Prediction Centre’s storm genesis-cum-tracker model as well as the US National Centres for Environmental Prediction.
Meanwhile, three districts in Tamil Nadu – Kancheepuram, Thiruvallur and Vellore – continued to show a rainfall excess of above 100 per cent during October 1 to 19.
The respective percentage figures were 127, 121 and 112, followed at some distance by the districts of Tirunelvei (rainfall excess of 83 per cent) and Chennai (72 per cent).