Parts of the rain-battered Tamil Nadu coast woke up to overcast skies this morning, especially from Cuddalore to Puducherry, Marakkanam, Cheyur, Kalpakkam and Kelambakkam, but less so over Chennai.
The India Met Department (IMD) has forecast heavy to very heavy rain at isolated places over coastal Tamil Nadu, Puducherry and Kerala today.
HEAVY RAIN FORECAST
It will be heavy at isolated places over interior Tamil Nadu and South Coastal Andhra Pradesh. Thunderstorms and lightning are likely over South Coastal Andhra Pradesh and Rayalaseema.
Another big blob of cloud is moving away from the coast off Puttalam and Mannar in Sri Lanka into the Gulf of Mannar, aiming at the Thoothukudi-Mandapam-Ramanathapuram belt in South Tamil Nadu.
The rudimentary circulation over South-West Bay of Bengal and adjoining Sri Lanka, which is responsible for whipping up the cloud cover over Lanka and Tamil Nadu, has persisted this morning.
According to the IMD, this is there for the longer haul and expected to have a major role in guiding an incoming low-pressure area/ storm from the Gulf of Thailand/South China Sea.
A tracker of weather systems at the US Climate Prediction Centre too had hinted at this, although the European Centre for Medium-Range Weather Forecasts remains non-committal.
The IMD projects that the circulation off Sri Lanka would create a trough reaching out to the Andaman Sea, to receive the incoming 'low'/ storm from the Gulf of Thailand.
TWIN STORMS IN BAY?
It also points to a likely follow-up storm being generated in the lower South China Sea even as the predecessor enters Andaman Sea, but follows the same track into the Andaman Sea.
The European centre agrees with this outlooks, but suggests that the second storm may not proceed beyond the South China Sea basin, and may end up over the Vietnam coast.
The IMD has it that the two storms represent pulleys linked by a single rope, as they break open their individual tracks for onward movement into the Gulf and onward into the Andaman Sea.
The pull from the horizontal trough in the South Bay would prove too strong that the first storm gets embedded in, and is guided towards the Tamil Nadu-Andhra Pradesh coasts by November 7/8.
Earlier, it was widely thought that a 'vertical' trough dipping in from North-East India would pick up the storm and deposit it over the Odisha-Bengal coasts.
According to the IMD, the second storm at the other end in the Andaman Sea would not venture farther into the Bay and instead break up over the southern parts of the Myanmar coast.