The picture below indicates the 850hpa winds on October 13th 2020. The initial system seems to keep Westerly winds active till that date and the consecutive system follows it, holds the key for timely onset of Easterlies if it keeps moving towards lower latitudes. The intensity and track of both the systems seems to be significant to watch.
If we further move on to look the prospects of NEM, the SST of Indian Ocean adjoined Maritime Continent holds the key as La-Nina years mostly depend on Systems based rainfall activity. An active South bay is favourable with the formation of –IOD, but models have divided opinion on this.
The image below shows the probability of –IOD formation but it’s uncertain till now.
An active Maritime Continent may trigger pulses and push them into Bay of Bengal.
Some Probabilities to be looked upon
1. If –IOD formation happens even for a short period from Nov 2nd week, it will pave way for active South Bay systems with the help of MJO propagation.
2. If the 200hpa divergence zone occupies over MTC adjoined South China Sea, we may keep a medium level confidence of Systems heading towards TN.
3. If IOD Modoki establish over Central Indian Ocean, that may open the window for West coast along with East Coast & an active GOM may favour whole TN.