The low-pressure area over south-east Arabian Sea has weakened on Monday after having presided over some of the wettest sessions on record during its slow grind from the Tamil Nadu coast.
But it leaves behind the parent trough in the sea, as it did while leaving the south-west Bay of Bengal earlier, which is capable of pulling in the North-East monsoon flows across the peninsula.
The rain belt will move to the South over Tuticorin, Kanyakumari and Tirunelveli and adjoining south Kerala on Thursday and Friday.
While Chennai and neighbourhood can hope to breath free from sustained wet spells, global weather models point to the possibility of on-and-off showers until December 19.
Earlier, the Indian Institute of Tropical Meteorology had said that the South-East coast (Tamil Nadu and Puducherry) are likely to witness above normal rainfall until this weekend.
What seems to lend credence to this view is the continued presence of the trough in the Bay of Bengal anchored to the South-West Bay of Bengal.
Interactive rain The Met has also alluded to the possibility of non-seasonal thundershowers and even hailstorm creeping up over south Madhya Maharashtra and Marathwada during the weekend.
This would happen as part of the interaction between the easterly winds over Tamil Nadu and opposing winds from a western disturbance digging low to the South on it way across Northwest India.
On Monday, the western disturbance was traced to the far West-North-West over the central parts of Iran. It will transit Afghanistan and Pakistan before making its presence felt over North-West India.
It is forecast to trigger heavy snowfall over Jammu and Kashmir from Wednesday.
Vigorous monsoon As for outlook for the next few days, the Met said that isolated heavy rain would occur variously over coastal Tamil Nadu, Puducherry, Kerala and Lakshadweep.