As we have mentioned many times in the past while the actual onset & withdrawal of NEM varies year to year depending on how the conditions prevail time to time as far as IMD goes the Northeast Monsoon or Post Monsoon Season as it it called runs between October 1st to December 31st. This is made from the perspective of maintaining statistics and with particular reference to long term averages.
Normally we stay away from going beyond a couple of days due to the Vagaries of Weather unless there is a specific need. Taking into account we are now slowly getting into that time of the year when Paddy cultivated under the early Samba Period start getting ready for harvest it makes a lot of sense to possibly provide some head-start to the farming community especially if there is a risk of flooding in the days to come.
Before we get to the last fortnight of NEM 2017 Season a quick recap of the rainfall pattern for the last 30 days. As one can see from the chart the core Northeast Monsoon areas got a raw deal as two tropical disturbances, both of which owed their genesis to the South China Sea, took an unlikely path robbing nearly a fortnight of active Monsoon period for large parts of Tamil Nadu.
It is always difficult to estimate well in advance especially under tropical conditions like India. Northeast Monsoon is particularly tricky due to sudden developments which could catch weather models off guard even 72 hours in advance as Cyclone Ockhi proved a few weeks back.
In the immediate context next week is likely to provide a weak Easterly Wave that is likely to provide decent rains to South TN & parts of Delta districts. Subsequently Models seem to toy with the idea of a possible disturbance evolving around Andaman courtesy of remnant pulse from South China Sea. Though there is still a lot of inconsistency in how models are treating this scenario the impact from this development is likely to be restricted to Sri Lanka and parts of South TN at best with no major climbing of latitude likely taking overall wind pattern into account.