The first fortnight of October marks the overlapping period for the retreat of Southwest Monsoon and onset of Northeast Monsoon. This is the period for widespread rains in Peninsular India.
Rainfall at this point of time is mostly the result of convective activities, which take place during the afternoon hours. With the onset of Northeast Monsoon, the pattern of rainfall changes. For instance, rainfall commences after late evening and continues till early morning.
In this article, we will bring you few characteristics of Northeast Monsoon, also known as Winter Monsoon in India.
a. Northeast Monsoon begins in mid-October and extends till December. There is no specific date for the onset of Northeast Monsoon.
b. Northeast Monsoon mainly affects five subdivisions of Peninsular India. These are Tamil Nadu, Kerala, Coastal Andhra Pradesh, Rayalaseema and South Interior Karnataka.
c. Yes, other places in Peninsular India also receive some rainfall during this period. Few spells of rain are witnessed up to Mumbai as well.
d. Northeast Monsoon is the main rainfall season for Tamil Nadu, which lies in the rain shadow area. Coastal areas of the state receive about 60% of the annual rainfall during this period. For the interiors, Northeast Monsoon accounts for 40% of the yearly rains.
e. The long period average NEMR (Northeast Monsoon Rainfall) is 312 mm, with a standard deviation of 84 mm.
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f. Northeast Monsoon rains are the result of easterly waves, cyclonic circulations and tropical storms.
g. October is the rainiest period, followed by November and then December. The rainfall table below will explain this statement. October and November comprise of the season for tropical storms originating in the Bay of Bengal.
h. The East Coast remains vulnerable to tropical storms. We can clue from Phailin, Helen, Hudhud and Nilofar, during the last 2 years.
i. The first burst of widespread rainfall in Coastal Andhra Pradesh and Tamil Nadu marks the onset of Northeast Monsoon.
* Rainfall figures are in millimeters.
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