The monsoon flows towards India may have been appropriated by twin cyclones in the Arabian Sea, but the Bay of Bengal is expected to soon come on its own.
Both these seas to either side of the Indian peninsula play out their own expected roles in fostering the flows and propagating the monsoon into the littoral countries.
CONDITIONS FAVOURABLE
Twin cyclones in the Arabian Sea are a rarity in the monsoon run-up and enough to drain out the flows and stall the progress of the monsoon into the Bay, where it reaches first.
The sheer power and intensity of 'Mekunu,' the latest, could briefly delay the monsoon onset over the South Andaman Sea, where it was scheduled to reach by today.
An India Met Department (IMD) update this morning said 'conditions are becoming favourable onset in the South Andaman Sea' in the next two to three days.
Current indications are that flows are converging around a circulation persisting for many days now off Sri Lanka and adjoining South-West Bay and just South of Tamil Nadu coast.
Sri Lanka has already been receiving heavy to very heavy showers over the past few days as the circulation pulled in winds from the South-West that lashed its South and West coasts.
KERALA ONSET SIGNALS
This activity in the South-West Bay could set off action in the South-East Arabian Sea off Kerala likely precipitating the onset anytime after May 27.
This is as per the outlook of the ensemble model of US National Centres for Environmental Prediction. It would not be surprised to see the South-East Arabian Sea develop a circulation soon thereafter, followed by a strong offshore trough along the West Coast of India.
The European Centre for Medium-Range Weather Forecasts too is in agreement here, projecting the formation of helpful troughs both along the West and East coasts.
This would take place even as the very severe cyclone 'Mekunu' nears its landfall over the Oman-Yemen coast, which is a strong testament for the strength of the overall monsoon.
Even more significantly, the IMD too agrees largely with this outlook, and shows a likely circulation - whether a 'low' or depression - penetrating land over the Bengal Coast.
OFFSHORE TROUGH
This is even as a strong offshore trough develops over the West Coast propelling rain right up to Gujarat. The strength of the trough is a proxy for the health of the monsoon.
Meanwhile, this morning, the strong flows had set up massive thunderstorms along the coast from Velankanni in Tamil Nadu right down to Colombo in Sri Lanka.
International in the North-West to South-West corridor over Colombo, including a LionAir and Qatar Airways flights, were seen flying around a thunderstorm sitting over Puttalam.
But an IndiGo flight flying in the Chennai-Colombo sector waded right into it as it was climbing down for landing at Colombo.
Thunderstorms infested the Gulf of Mannar sector between Colombo-Dambulla-Anuradhapura-Jaffna in Sri Lanka and Karaikudi-Rameswaram in Tamil Nadu, India.
This morning, rain clouds from this region extended into the South and adjoining Central and East Bay of Bengal, just bordering the Andaman Sea.