The low-pressure area over South-West Bay of Bengal and adjoining Sri Lanka may not have intensified yet, but models see twin storms spinning up over the seas this week, separated by the peninsula.
Satellite pictures this morning showed most of Sri Lanka shrouded by thick cloud cover, extending into the Gulf of Mannar, and onward into Kanyakumari-Nagercoil over peninsular tip of India.
Some clouds are located over Aruppukottai, Madurai, Ramanathapuram, Mandapam, Chidambaram, Vriddhachalam, Ulundurpettai, Villupuram and Tirukkovilur.
The prevailing 'low' is set to cross Sr Lanka and skirt the peninsular tip of India to emerge into the Lakshadweep Sea and adjoining South-East Arabian Sea over the next two days.
By this time, a fresh 'low' materialising over the South-East Bay would have moved in and started to gain traction, moving west-northwest towards India's East Coast (Tamil Nadu-Andra Pradesh coast).
The 'low' in South-East Arabian Sea would intensify into a depression and may start move to the north, unlike further west into the outer seas as prevailing easterly winds should cause it to.
Instead, an incoming western disturbance from the opposite direction and dipping into the Arabian Sea from the North, would force it to move first to the north, and later, along with it to east.
The western disturbance moves east and should take the intensified 'low' towards the West Coast of India (Karnataka-Goa) by December 6, if the European model prediction is any indication.
Fresh 'low' in Bay
The westerly winds from the western disturbance would have taken the sting away from the system, and weakened it before it reaches coast back as a 'low,' bringing in some unseasonal rain.
Meanwhile, the 'low' in the Bay too could intensify into a depression, but weaken under the influence of the same western disturbance, before crossing the South Coastal Andhra Pradesh coast.
The landfall is likely to occur to the north of Chennai by December 5, a day before the Arabian Sea system lands over the Karnataka-Goa coast.
The Bay is far from finished in terms of its capacity to generate low-pressure areas during the season, since a fresh one could likely shape over its the eastern fringes in five to six days from now.
According to an advance weather tracker of the US Climate Prediction Centre, this is likely to trigger an easterly wave (elongated, horizontal low-pressure area) headed towards Sri Lanka/South Tamil Nadu.