The Northeast Monsoon is responsible for giving good rains over the state of Tamil Nadu. The pull effect from the low-pressure area has drenched Tamil Nadu in the month of October.
Northeast monsoon has been normal across Tamil Nadu with 196 mm rainfall in the first 30 days of October as against the normal of 172 mm. As the low-pressure area strengths off the east coast, it pulls strong winds from the Bay of Bengal. While the easterly and southeasterly winds activate an offshore trough, abundant incoming moisture from the Bay of Bengal brings heavy rainfall to the coastal districts of Tamil Nadu.
Successive cyclones in the Indian seas holdback the rainfall activities which are usually seen during the Northeast Monsoon season. The cyclones are formed either in the North Andaman Sea or the Southeast Bay of Bengal. And this is the origin of Northeast Monsoon as well which unfortunately gets consumed by the cyclones. Hence, disrupting the Monsoon cycle.
The surplus of Northeast Monsoon in Tamil Nadu for the month of October is now getting subsumed because of the subdued performance in the month of November until October 7.
Rain deficiency in Tamil Nadu:
The figures tell us that the month of November has seen subdued Northeast Monsoon activities courtesy cyclones in the Indian Seas.
The above graph shows us that it was in 2014 when 40% of surplus rain was recorded in the month of October. And, now in 2019, 14% of excess rains have been recorded in October. While in 2013, 2015, 2016, 2017 and 2018 the month of October was rain deficient, wherein 2016 was majorly deficit by 63%.
In the month of October, Nilgiris recorded a whooping of 116 mm of rain while Chennai recorded only 5 mm of rain. The varied intensity of rainfall activities has been a sight in different districts of Tamil Nadu.
The Cyclone Bulbul in the Bay of Bengal is likely to take an exit in about 48 hours or so. As the system will move, possibly the easterlies will establish and will again help in reviving the Northeast Monsoon. The re-establishment of the Northeast Monsoon will form once the Cyclone makes an exit.
By now we have understood the fact that any system in the Bay of Bengal impedes the Northeast Monsoon.
In the coming days, the southern districts of Tamil Nadu are likely to witness light rain activities with one or two places witnessing moderate showers as well.
Image Credits – Skymet Weather, The Hindu Business Line
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