Since the start of October, the Bay has been very active seeing time to time circulations particularly over Central BOB. The reason behind this was the convective phase of MJO which has been nicely positioning itself over the Maritime Continent which made the South China Sea hyper active. As always the case, the remnant pulses entered BOB via North Andaman Sea crossing Vietnam Landmass. The surging NEM trade winds over SCS also made sure the circulations there intensify well into a cyclone.
Even though the Northeasterly Trade winds are stronger, the systems over South China Sea has prevented any sign of Easterlies entering Andaman Sea which is a worrying sign for most of us regarding NEM 2020 onset. Nevertheless hoping the worst is behind we will get a clarity on it as the week passes by.
From last week the trending topic of weather is about the current broad UAC lying over the Central Bay of Bengal which in turn a remnant of a past system from SCS. This broad UAC is set to develop into a LPA in the next 12 hours or so. Due to the broad trough like nature of the circulation, there has been multiple vortices developing which indeed is making models struggle a bit which in turn might reflect over the precipitation prospects. Added to this an incoming Mid-latitude Trough is expected to interact with the upcoming LPA after 21st October making the LPA move north.
As most models and its ensembles expect the LPA to come closer to South AP coasts, heavy rains with very heavy rains can be expected along SAP coast. A slight shift of the circulation to the south about 1N latitude will do wonders for Chennai and adjoining NTN areas which is still a good possibility. Nevertheless, a good spell or two of rains await Chennai between 19-21 October. Once this LPA moves away, we can expect some good progress on the Monsoon Withdrawal. Let us accept and enjoy whatever Nature gives our way.