North east monsoon in India
North east monsoon in India is also called as Post Monsoon or Retreating Monsoon. The southwest monsoon starts in North India by the end of the second half of September because of the southward shifting of pressure belts. This wind gets backs from the Indian peninsula and blows towards the Bay of Bengal.
The Coriolis forces deflect this wind and make this wind blow from the Northeast and it is known as North-East Monsoon or Post Monsoon season. The Northeast Monsoon in India is connected with the formation of the North-Easterly wind system over the Indian subcontinent.
From this season, the states such as Tamil Nadu, Andhra Pradesh, Kerala, and south interior Karnataka get good rainfall that almost 35% of its annual rainfall. The Retreating monsoon creates a large-scale loss of life during the storms that occur frequently in Tamil Nadu, Andra Pradesh, and some parts of Karnataka.
During these seasons, strong winds and storms hit the coastal regions, and the daytime temperature falls rapidly all over the country. The average temperature over North-west India shows a decreasing trend from 38 and falling to 28-degree celsius in November.
Ncert Notes for Retreating Monsoon
The below notes from 11th book
Season of Retreating Monsoon
The months of October and November are known for retreating monsoons. By the end of September, the southwest monsoon becomes weak as the low pressure trough of the Ganga plain starts moving southward in response to the southward march of the sun. The monsoon retreats from the western Rajasthan by the first week of September.
It withdraws from Rajasthan, Gujarat, Western Ganga plain and the Central Highlands by the end of the month. By the beginning of October, the low pressure covers northern parts of the Bay of Bengal and by early November, it moves over Karnataka and Tamil Nadu. By the middle of December, the centre of low pressure is completely removed from the Peninsula.
The retreating southwest monsoon season is marked by clear skies and rise in temperature. The land is still moist. Owing to the conditions of high temperature and humidity, the weather becomes rather oppressive. This is commonly known as the ‘October heat’. In the second half of October, the mercury begins to fall rapidly, particularly in northern India. The weather in the retreating monsoon is dry in north India but it is associated with rain in the eastern part of the Peninsula. Here, October and November are the rainiest months of the year.
The widespread rain in this season is associated with the passage of cyclonic depressions which originate over the Andaman Sea and manage to cross the eastern coast of the southern Peninsula. These tropical cyclones are very destructive.
The thickly populated deltas of the Godavari, Krishna and Kaveri are their preferred targets. Every year cyclones bring disaster here. A few cyclonic storms also strike the coast of West Bengal, Bangladesh and Myanmar. A bulk of the rainfall of the Coromondal coast is derived from these depressions and cyclones. Such cyclonic storms are less frequent in the Arabian Sea.
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Below notes are from Ncert 10th book
Retreating/Post Monsoons (The Transition Season)
During October-November, with the apparent movement of the sun towards the south, the monsoon trough or the low-pressure trough over the northern plains becomes weaker. This is gradually replaced by a high-pressure system. The south-west monsoon winds weaken and start withdrawing gradually. By the beginning of October, the monsoon withdraws from the Northern Plains.
The months of October-November form a period of transition from hot rainy season to dry winter conditions. The retreat of the monsoon is marked by clear skies and rise in temperature. While day temperatures are
high, nights are cool and pleasant. The land is still moist. Owing to the conditions of high temperature and humidity, the weather becomes rather oppressive during the day.
This is commonly known as ‘October heat’. In the second half of October, the mercury begins to fall rapidly in northern India.
The low-pressure conditions, over north-western India, get transferred to the Bay of Bengal by early November. This shift is associated with the occurrence of cyclonic depressions, which originate over the Andaman Sea. These cyclones generally cross the eastern coasts of India cause heavy and widespread rain. These tropical cyclones are
often very destructive.
The thickly populated deltas of the Godavari, the Krishna and the Kaveri are frequently struck by cyclones, which
cause great damage to life and property. Sometimes, these cyclones arrive at the coasts of Odisha, West Bengal and Bangladesh. The bulk of the rainfall of the Coromandel Coast is derived from depressions and cyclones.
Distribution of Rainfall
Parts of western coast and northeastern India receive over about 400 cm of rainfall annually. However, it is less than 60 cm in western Rajasthan and adjoining parts of Gujarat, Haryana and Punjab. Rainfall is equally low
in the interior of the Deccan plateau, and east of the Sahyadris. Why do these regions receive low rainfall? A third area of low precipitation is around Leh in Jammu and Kashmir. The rest of the country receives moderate rainfall.
Snowfall is restricted to the Himalayan region.
Owing to the nature of monsoons, the annual rainfall is highly variable from year to year. Variability is high in the regions of low rainfall, such as parts of Rajasthan, Gujarat and the leeward side of the Western Ghats. As such, while areas of high rainfall are liable to be affected by floods, areas of low rainfall are drought-prone.
Conclusion
The North East Monsoon is a crucial aspect of India’s climate system, bringing much-needed rainfall to southern peninsular India. Understanding its dynamics and impact is essential for various sectors like agriculture, water resource management, and disaster preparedness. For UPSC aspirants, a thorough grasp of the North East Monsoon is vital, as it is frequently tested in the geography and general studies papers.
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1.North East Monsoon in India Upsc 10th Ncert Notes Pdf
2.North East Monsoon in India 11th Ncert Notes for Upsc Pdf