The normal date of onset of Northeast Monsoon has been surpassed and its ingress is awaited. As it matters most for the southern state of Tamil Nadu, the fingers still remain crossed for the exact date of arrival. The conditions possibly will be favourable by the month-end or early days of November.
The Southwest Monsoon has to vacate first to pave way for the Northeast Monsoon. The delay in commencement of this process was further derailed by the frequent appearance of weather systems in the Bay of Bengal. The substantial extension looks imminent and withdrawal may not complete before 28th October. Accordingly, the onset of the Northeast Monsoon is expected to follow soon, listing it to be one of the most delayed, almost aligned with 2016 and 2018.
The track record of onset of Northeast Monsoon has been wavering and is seen getting delayed more often than not by one week or more. There is a visible reflection of this delay in the seasonal rainfall figures for nearly all the sub-divisions covered by this mini-monsoon. In the last about 15 years, the earliest onset for Northeast Monsoon on record was 2014 (18 October) and most delayed one in 2018 (01st November).
The changeover of winds to Easterly/Southeasterly by 14 October precedes the normal onset date of 20th October. The weather system forming in the Bay of Bengal and their subsequent travel across central and southern parts inhibits the establishment of the seasonal pattern. Once established will also get changed subsequently with the formation of Depression or Cyclone in the Bay of Bengal but the initial set up is mandatory for the official arrival of Northeast Monsoon.